i was putting some lights up in friends bathroom and the replacement lights had multi stranded cables i put it into the connect and screwed it up pulled and it come out the connector so i though thats not safe, i had a crimping set i brought from lidle and i put like a small tube round the multiple strands crimped that onto there, did twisty 90* bendy thing it didnt come off so i put it into the connector block thingy and screwed it in made sure it didnt come out off that and then put the light to the ceiling, so i think i mad a fairly reasonable effort to make it safe. my general rule of thumb is pull on it and make it look pretty, if it dont brake with a pull and it looks need then its more than likely safe
Over-tightening terminals on copper wire is a favourite. Fine for a few years but the excessively squashed conductors can fail and create points of high resistance EDIT: lol just got to the bit where this was mentioned as a DIY mistake but the pros do it all the time 😅
Fun stuff and so typical mistakes for many DIYers. But the wound up extention cord running hot, has nothing to do with inductance. It simply the resistance of the cable that cause it to heat up - but being rolled up like a coil, the heat can not escape from the cable very easy (compared to if the cable is rolled out), so the temperature rise quite a lot As the resistance of copper also goes up by the temperature, this causes it heat up even more in a sort of thermal runaway. This can cause the coil of cable to get toasty, very quickly.
three thumbs up, the out and return are parallel, so loop area is negligible in this instance , so inductance is negligible, surprised at Jordan for getting that wrong.
Right, and I would like to add that, even if there were a significant inductance (which is not there because the magnetic fields due to the two opposite currents cancel almost perfectly) it would not lead to any power dissipation, only to a lossless voltage drop. It is only the resistive part of the impedance that leads to power dissipation and Joule heating. I do not know why this incorrect belief about the hypothetical inductance and even more hypothetical associated power dissipation of coiled cables consisting of two conductors with opposite currents is so common: I heard it for the first time in high school when I was working part time for a local tv station: a technician from.a local tv production company told me that power cords for halogen lights should not be wound in operation motivating the recommendation with the incorrect inductance argument.
Extension leads - Inductance is not the problem, it's the resistance that creates heat. Cable is rated for a situation where air can circulate around it. Winding it onto a reel adds insultation so the copper temperature rises.
Agreed. Inductance cannot play a role, as you have two coils parallel (two in which current flows, the earth is an open circuit on the end, if the appliance has no earth leakage), and the current flowing in them is always opposite , so the magnetic fields of the two cancel out. Also, inductance does not build up, it is a property of a configuration of wires (large for a coil, very low, e.g., for a twisted pair). What is building up is heat, no matter how it was created.
One other thing not mentioned, but something I've not seen done in a fair number of outdoor DIY cabling setups are Drip Loops. Instead you tend to see cables running straight down a wall, right into a junction box with nowhere for the water to go!
I've seen the same done by professional CCTV installers recently. Cameras had gone out. I checked the weatherproof enclosure, unscrewed the cover and about a litre of water poured out. All cables were top-entry, no drain hole, system had worked until water got up to the level of the power supply for the network switch. Also not-so-professional cable contractors (I won't name names but let's just call them the S*** Wiring Guys) running Ethernet feeds into the tops of Wiska 308s or through drilled-out holes in the rear. As they fail the cables just get jelly-crimped now as if the jack is replaced it just rots again.
Exactly. I'm a DIYer but I was awake in class when the teacher told us about gravity. I installed a cable in my loft that goes downwards to a junction box but does a wide 'U' before rising up to enter from below. A little bit of thought goes a long way.
Exactly! Bifilar coils like this cancel out the magnetic field nearly completely. Not knowing about reduction Factor on stacked cables and it's danger is a typical DIY mistake.
To expand on these accurate comments by op & @AzrethK9. Yes the coil is definitely Bifilar and therefore a non-inductive coil for this purpose (basically the magnetic field of the neutral cancels out the live, why you can't use clamp meters on power cords). Additionally self-induction is not a method of energy dissipation, it is a form of energy storage. If the coil was inductive the energy world be stored in the magnetic field and released later in the AC cycle. This why PFC devices are called for on inductive loads, they don't affect your real power consumption, just the power factor. What this is, is an example of a hazard caused by bundling many (slightly resistive) conductors together and there being nowhere for the heat to go. Think of it like wrapping the inner wire in a blanket, and an electric blanket at that. This same hazard would occur if there were many separate cables all carrying this current, this is a hazard electricians should understand. I think this myth may come from two places, people knowing a coil can be inductive, assuming it is because they don't know what an inductor is; and then assuming that one thing they now see is the cause, ignoring the obvious real cause they should already know about. The other possibility is people are thinking about induction hobs, which is a whole different situation, firstly they use an inductive coil and secondary (pun intended) there is a pan to act as the other, shorted, winding.
I'm in my 50's and did a 5 year apprenticeship as an Electronics Technician when I left school. I then became good friends with an Electrician who over the years taught me a lot about household electrical wiring etc. As a result I feel that I'm relatively competent as a DIYer and myself have seem some hacks that were so dangerous I physically shuddered at them. Every bit of work I've ever done on my house electrics, I have an electrician come out and check it. When I built my workshop in the garden 20' x 10', I fitted a 20 socket ring main and 12 light ring. I ran the Armour cable to the CU and had an electrician come check it and connect it up. He said he had no qualms with connecting it and certifying it as the job was good. My point isn't to "big up" my skills and knowledge, but to point out that not all DIYers are terrible, some of us actually go out of our way to make sure we do a good job because we realise that our lives and the lives of our families are very much on the line.
Indeed so. I'm also an electronics engineer and would never make any of the DIY mistakes mentioned here. I also know that it is not inductance that causes a rolled up extension lead to get hot! Unfortunately Part P has turned us DIYers into criminals and, by making the relevant standards inaccessible to non qualified persons made it far more difficult for those of us trying to do a decent job to do so.
The issue for you, that today, some of the work you did is considered _notifiable_ and by law, the Building Control department of the local council has to be notified. Even if you are competent as a DIYer, you still have to notify the Building Control and they will tell you what certification requirements are needed. And as you don't hold any formal qualifications, and no membership of NICEIC or NAPIT, then they will require that a qualified electrician inspect and sign it off as being compliant to the wiring regs. So I think it is important to not send out a message that anyone can just go along and do their own electrical DIY and get an electrician to sign it off. There is more to it than that.
@@John_LNo, it is not true that Part P has turned people into criminals. I have repeatedly seen statements made by even electricians that say people can't do their own electrics. That is not what Part P of the building regs says. Part P says that the work has to be done to compliance of the wiring regs, and be certified by somebody competent and it talks about notification to the building control department.
@@deang5622 This is true but by making the said wiring regs only available to certified personnel the effect is to make it nearly impossible for the conscientious DIYer to do a compliant job. And the DIYer is criminalised unless his work is inspected, even if it is not notifiable work. The practical effect is indeed that the DIYer cannot do his own electrics, no matter how competent he is.
@deang5622 yes but you obviously missed the part where I said it was inspected and checked/tested by a qualified person who then issued the appropriate paperwork. the work I did on my workshop was done back in 2011and as I said, I had an electrician come out to connect it to the CU, I left all the socket fronts off and the lighting covers on the flourescents off so he could see the job I had done and also marked out my cable runs that are behind the OSB that lines the inside, I also have a couple of covers that give easy access to some of the areas where the cable runs incase I need to do any work on it. He was happy enough to sign off on it and to connect it to the house CU. I ran the Armour Cable and routed it to the CU in the garage and again after testing it he was happy to sign off and complimented me on a good job. The result is, I have an ele tri ally safe workshop that has been in use now for 13 years with zero issues (except a small leak in the roof I just had to fix🙄). I have also had another electrical inspection about 2 years ago and they checked the workshop because its connected to the household CU so included it as partnof the house and again had a clean bill of health. Based on all this, why am I breaking the law? Yes I did the work, but didn't make the final connection and it was all tested by a qualified person 🤷
Yep, it doesn't really have to be a very expensive device either, but testing that it shows a circuit before turning off the power at the distribution board and the looking for the difference is really important. Even when having done this I do have the slightly (bad) habit of intentionally bridging live and neutral because if there's a pop and a circuit breaker kicks in, I'd rather that it do this when I expect it!
Strickly, you should also check your tester immediately AFTER checking the circuit - to ensure that the tester didn't fail JUST BEFORE,or during) your test ! Pro's will have some independant voltage souce -or use knowingly energised circuit.
@@tridentmusic5570 You are right, but I haven't seen anybody doing that, except the guys who work in secondary substations. In household installations it is more common to create an intentional shortcut after testing just to be on the safe side. At least that's the case for Germany. Cheers Andreas
Coiled extension has current running in opposite directions (hot ("live") out, neutral back) so induction is cancelled out. It's simply that with enough current the cable heats and because it's coiled the heat isn't dissipated as it would be on an uncoiled line.
The cord is not about induction but simply resistance. When it is wound up it cannot dissipate heat and cool. Once it heats up the resistance increases and it heats even more. All those thermal protections, as well as fuses and circuit breakers are in case an overload happens. They are not some permission to load as much you can and rely on them to cut.
Absolutely correct! At any point in time the current in the L and N conductors will be flowing in opposite directions and are physically very close together so the magnetic fields cancel.
The resistive heating is an issue also, if wire is heat insulated. Adding heat insulation to a wall or ceiling without remaking electric installation may be fire hazard. Even more important in boat or camper. Low voltage cabling uses high current, and hiding a 1,5 mm2 wire inside good foam insulation and using it just with 120W may be enough to cause a fire. With battery a shorcut ends up to red hot wires very quickly, and insulation can melt and cause short circuit.
Another common mistake is pushing the wire too far into the terminal so that the screw is tightened onto the outer insulation of the wire rather than the copper, thus no connection. Particularly bad if done to the earth.
Great video Jordan. As a DIYer I think the advice you're giving is spot on. Discovered the coiled extension risk the hard way as a kid in the 80s (those were the days!). I think most competent DIYers, and professionals are already aware of these points but make mistakes out of haste, lack of the right tools to hand, or a an optimistic approach to risk rather than ignorance.
As a DIYer, after seeing this, I feel very competent in my work. I use a very old and reliable Fluke multimeter for various tests, would never dream of all the things you've covered here so I must be in the 'safe' zone (although I have electrocuted myself twice but isn't that to be expected, the first time was as a young child with poking wire in a socket🤣). After visiting my loft, I can say that it's a mess, clearly the electrician wasn't to our standards. I have a 10 meter EV charger cable which I always unwind regardless how close the car is, just to me, common sense.
The whole plugging extension inti extension doesnt really apply here thats why the fuse exists. its actually quite hard to overload ive tried just out of interest. Now all these are common sense i genuinely dont get how people think any of this is ok. Ive seen people do it and my mind just cant comprehend how they think its safe.
Also 'idiots' are quite willing to bypass fuses because to their mind a blown fuse is because the fuse is faulty, like a blown light etc, therefore they jury-rig a fix because of that perception of 'what do these so-called 'experts' know? It doesn't blow when I fix it . Therefore I know better than them. It's false logic, but ignorance and ego drives them onwards. QED.
It's not inductance that overheats the extension lead as the fields will cancel from live and neutral carrying currents in opposite directions - it's a lack of thermal conduction to circulating air of which three is none when it's tightly wound.
@@chrishard7616 It's the right cross section when unwound and in free circulating air. When tightly spooled the I²R loss is too high when concentrated in the small space. You could have a thicker wire to reduce the i²R loss so it doesn't overheat when tightly spoiled but of course a thicker wire wouldn't fit on the same size spool and you'd end up with a much bigger, heavier and more expensive extension reel. These things are always compromises. It will work at 13A when unspooled and perhaps only 4A when spooled (continuously) or short periods at 13A to limit temperature rise, perhaps relying on a thermal cut out switch.
I’m a diy enthusiast and became one so many years ago because of what I saw ‘professionals’ do. Poor quality of work was the main reason but also the cost. Over 40 years I have become a jack of all trades, who has high standards way above what some contractors have. Just look at the quality of work put into new builds…. Shocking.
Good call out with the coiled-up extension lead. That is something I don't see enough people talk about, to be honest. (As others have pointed out, it's not actually about induction, it's actually just about not having enough airflow to properly cool the wire, but the main point is still a good one.) And yeah, you had a pretty nice one there with a thermal cutout and everything, but a lot of them don't have that. It doesn't even have to be one of the really long ones with their own carrying spool like that one was, just a plain extension wire that somebody has left coiled up in a loop sitting on the ground can get a lot hotter than it's supposed to if a decent amount of power is pulled through it. And the reason you don't want extra exposed conductors even inside a box is because sure, it works _now_ but then later somebody comes on and moves something around and something falls on one of them or one of them gets pushed into something else and all of a sudden you've got a dangerous short. It's not just about getting things to work right at that moment, it's also about making sure they won't go horribly wrong somewhere down the line, too. Oh, and with the screw terminals, one other important point, IMHO: *Always tighten them twice.* Screw them down initially, then move the rest of your wires around, get everything properly in place, and get ready to button the whole thing back up, and then go around and _make sure all the screw terminals are still tight._ It's amazing how often they can become loose just from moving stuff around after you've initially tightened them (part of the reason I much prefer other types of connectors like the WAGOs when they're an option).
Hi Jordan, I enjoy your video's but I am not an electrician I only do the basics, one of my biggest electrical pet hates is wrong size fuses in plugs about a month ago we bought an electric hand held food blender only 175 watts but fitted with a 13 amp fuse that to me is a safety issue by the manufacture and against the warranty I swapped the 13 amp fuse for a 3 amp it works fine its just down to basics. I can understand with power tools a 400 watt drill will be fitted with a 5 amp and not a 3 amp because of the start up of a motor. Great video thanks for showing Take care
The fuse protects the wire not the power draw of the device. Although you may have a low wattage it may well have a higher inrush current and that could blow the fuse. Unlikely with the figures you have given and fuses have a degree of inrush allowance.
@@davideyres955 Hi David, thank for your reply, but would a 13 amp fuse blow on some thing with very little power if there is a fault on the appliance the cable is only 0.5mm twin flat flex, I am not electrician but I was told to use the correct fuse for the wattage of the appliance, once again thanks for your info
@@shaun30-3-mg9zs The fuse should be sized to a maximum of what the power cable of the device can handle, or 13A, whichever is smaller. Most appliances have cords which can handle 13A, even if the device itself is never intended to draw that much, so a 13A fuse in the plug is fine (it will still trip before anything gets hot enough to cause damage/fire). However, if your device has a cord with 0.5mm^2 conductors, then that probably shouldn't go over 5A or so, so yeah, a 13A fuse is arguably wrong in that case.
There is some reason for it I'd argue, especially when electrics are one of the most dangerous things one can play with in a house, alongside gas. It has to be done right, there's no room for corner cutting or mistakes.
I've employed several 'qualified' electrical contractors and had some really shoddy work completed. Be carefull not to employ an electrician that doesn't know what he or she is doing.
Back to school for Jordan with the "induction" heating... If it was wound around a metal core with a load more current at a frequency in the kHz, then maybe...... Boring old resistance heating I'm afraid. Do your media team not fact check?
Well, the explanation was not quite right, but the actual issue and main point is still entirely valid, so I'm still glad he mentioned it, at least. Coiled up extension leads can get a lot hotter than they're supposed to (really just because of lack of airflow for cooling), and that can actually be a real problem in some cases, so you definitely should always uncoil them and separate them if you're pulling any kind of significant power through them...
@@foogod4237 when you say “not quite right”, you mean not even close…… the same outcome does not not justify an incorrect explanation. Especially so when the whole video is berating “DIY” practises in the first place. And even more so when these supposed DIY practices have plenty of precedent of being done by so called “professionals “ in the first place.
There are two different things in this which the video presenter has confused. 1. Induction coil 2. Solenoid We don't have 1 here, we have 2. And in the case of 2, we actually have two solenoids interwoven, comprising one turn of line one turn of neutral and this then repeats for the full length of the solenoid. Both line and neutral coils are wound in the same direction, so both coils will produce a magnetic field each in the same direction if the direction of the current in both coils is in the same direction. However, as we know, the line and neutral currents are in opposite directions which means the magnetic fields are in opposite directions. Assuming no earth leakage, then the line and the neutral currents and the same magnitude. The net effect is the two magnetic fields are equal and opposite and cancel each other out. So no magnetic field. It is very common for electricians not to understand much about solenoids other than they create a magnetic field. I have seen had an argument with a sparky on this channel that tried to argue the inductance was zero and quite firmly stated that the inductance is not related to the physical properties of the coil. Something seriously going wrong with their education in inductance and solenoids. But I guess, an electrician trains electricians. So the myths perpetuate.
@@deang5622 For future reference: A) The inductance is independent of the current only as long as the materials forming the magnetic core behave linearly. That means an inductor with an iron core will have a current dependent inductance if said current gets high enough. B) The inductance for a coiled twin-lead is indeed not higher than for a straight twin-lead of equal length if the distance between conductors is much smaller than the distance between windings. For the extension cable those distances are comparable so I am not sure. This is because the magnetic fields of both conductors cancel and so the different turns cannot affect each other. C) The inductance ultimately doesn't matter much because inductance doesn't draw real power and create heat. Technically it draws reactive power and that creates more heat in other parts of the wire but realistically that effect should be negligible.
Using snips to remove the outer sheath and cutting into the inner insulators and partly exposing the copper. Not always visible but a real danger for getting a shock.
I had a case where the customer connected a 3 phase motor by himself and did just that. He made accidental cuts into two-phase and neutral insulation. Since there was still air for insulation, it worked. It had a motor protection breaker on the circuit and it started shutting off regularly (once or twice a week). So he decides to change the circuit breaker, at first it seemed to stay on a little longer, but soon the same pattern. A little later he also replaced the motor, still the same. When I went there I suspected insulation, but insulation tests with 1000V did seem ok. I still decided to open everything on both sides, to check cable and connections and that's when I noticed these cuts. Fortunately, there was enough cable to cut this section off and do it again. Since then, no problems. He checked that motor connection box dozens of times and me and other guys with electrical backgrounds checked the box also and saw nothing. Cuts in insulation where straight, both halves were kept together so no exposed copper, no moisture and no signs of a short circuit.
7:45, use ferrule crimp ends (shoelace crimp). Not only do you crimp once with your tool, the screw itself will compress the wires against the ferrule and they won't separate or spread out, ensuring a solid connection. I don't know why people don't use them on stranded wire outside the EU. Every time i see one without a crimp, I cringe.
Must admit I like using ferrules - got some a few years ago (with crimp). While not an electrician as a retired electronic engineer I know more than most.
I need two on the second meter tails i just upgraded (from the insufficiently sized cable the previous diyer did). But I'm not going to buy a tool just to crimp two ferrules!
@@imaginitivity7853 I crimp hundreds of wires every day since I'm building automation cabinets with PLCs and drives and other stuff, so I really need it, but on installations with solid core, I guess you don't really need it. But my point stands. Multi core wire should be always crimped unless connected to a spring terminal. Push terminals and Screw terminals need the crimp.
Speak for yourself, don’t keep denigrating DIYers who know what they are doing and do better than some of the cowboy electricians that are out there. As a DIY er I’ve improved the appalling wiring (probably done by the builder who built his own house) in our 1970s house. Single ring for an entire 3bed detached house including immersion as a spur off the ring. It had lots of wire nuts and twisted connections! Borrowed neutrals. I’d just go read BS7671 and the on site guide and do it properly. Added separate radial for the immersion, which is no longer used but it supplies power to the loft for the digital shower and axial fan, I split the single ring into two rings (proper and continuous), re wired the kitchen, garage and boiler house. They used to stock the IEE wiring regs in WH Smith’s in town, I used to go read and memorise before doing work. Only thing I’ve lacked over the years is a MFT. But subsequent PIRs (EICR for the youngsters) have shown the installation to be sound including the fixed borrowed neutrals. Did have reputable a local spark in to change the CU to full RCBO board 14 years ago and recently had spark in to replace the RCBOs and main switch but kept the enclosure. Not paying Artisan prices to do something I can do myself to a proper standard!
I guess the problem is they rarely come across good DIY as they assume all good installs are by sparkies and all the poor stuff is by DIY Dave (being a David it’s even more grating). Frankly there are some horrible wiring bodges I’ve seen and some of the crap jobs I’ve see. In my house done for the sake of speed rather than quality and maintainability are annoying to say the least. 1mm cable for the light that snaps because the copper has work hardened and not enough slack on the cables. However there are a ton of things I would not know like how to design earthing arrangement on a solar install with UPS functionality that are defo a job for a qualified sparky. The problem is people like you are probably a rare breed.
I work as an Electrician in Australia and I think the reason DIY is generally frowned upon is because the potential risk involved for one and the propensity for DIY people to think they're ready to tackle certain aspects of the job they aren't prepared for. On the flip side, if your DIY is up to par, I would assume most electricians will just assume it was professionally done which strengthens their cognitive bias because in their eyes all they see is the DIY fuckups. Side-note: It's illegal in Australia to work on electricity without being licensed so maybe it's different wherever you guys are from (:
@@cmm287 In the UK, there is quite a lot of DIY work permitted: pretty much anything internal except bathrooms or new circuits from the consumer unit (and anything else can still be done DIY if notified to the council building control and then electrically tested by a professional). Problem is that any work you do must be tested to BS7671 which requires calibrated test equipment that no DIYer is likely to own, and most sparkies won't be interested in testing DIYers work for them. The irony is, of course, that when was young and irresponsible, I installed an outside light (fused down from a spur on a socket circuit) and tested my own work as best as I could using 40-year old test equipment... couldn't find an earth. I then discovered that the socket spur (professionally installed some years prior) I was using to feed the light was itself spurred from another socket spur (not how it should have been done) and that that the first spur wasn't connected to earth: 2 unearthed sockets. Hence, I, the DIYer was obviously the first person to check my own work with any test equipment whatsoever, and also the one who ended up correcting the fault, only because I was testing my own DIY work, albeit not with the calibrated test equipment I should have been using.
In reality why is there any issue daisy chaining 4 way type extensions, given, in the UK where this is filmed, each plug (including the primary extension) has a 13A max fuse, the most you could pull in the entire circuit is no different to it being on it's own. The fuse will blow and assuming the extension lead is suitably manufactured and tested, there should be no additional risk.
The issue is that many of them aren't suitably manufactured and tested. People buy stuff online from wherever they can find it cheapest, and that results in a lot of really poor quality. How easy it is to find a partial earth pin in plugs for all kinds of things these days is sort of scary, & switched multi-gang extensions can be particularly gnarly with switches not rated for the mains or being spongy & audibly arcing. The fuse may eventually blow, but that doesn't mean you won't get heat build-up and scorching before it happens.
13 amp fuse won't blow till you pull 26 amps or so through it, though. And the ring main will have a 30 amp circuit breaker. It's quite possible to get wiring running hot without the fuse blowing. If that wiring is enclosed somewhere - say run under furniture, tucked behind curtains - then the heat can't escape, and can build up to 'burning down the house' levels.
In our first house I was swapping out some ceiling light fixings. So, I turned off both "Lighting" Fuses at the box. But, in a bungalow, with full access to the cables in the loft space, I quickly found that the bathroom lighting was hooked into the socket ring. Quickly and sharply. Learnt an important lesson about other people's work and the value of test equipment that day.
In my bungalow somebody had wired the garage by stringing an unsupported t&e across the 2' gap from the house, which I managed to twang a couple of times while carrying a ladder. Even better, it was spurred off the socket in the attic that was for the boiler and the garage had a dodgy roof so, in wet weather, it would trip the RCD that fed half the house and the only way to isolate it was to turn the boiler off. I paid some sparkies £250 to put a separate RCD in for the garage and an armoured cable running under the decking instead of looming over me. Well worth it.
I well remember a case when I was on a Tech Theatre Course back in the Eighties. The theatre was adjoining the old Victorian house, and while the LX had it's own supply, other equipment tended to be run from the house's supply. On this show the whole stage had been painted with size paint and then sealed with Emulsion Glaze (PVA). During the night there had been a leak and the stage was soaked, walking on it would rip up the paint, and that was a key part of the show. So. Every heater we could find was put on stage to try to dry it before the afternoon Matinee. Couldn't even mop it, it was so soft! So the extension cable (at full length), got hotter and hotter, then blew the fuse. The Chief LX on the show went to the fuse box and pulled this huge, palm sized ceramic MK fuse out without thinking, and got MK branded into his palm. Nasty!
Resistive heating only. There is no net magnetic field created by a coil of mains cable as there are two currents passing through two coils in opposite directions. No net magnetic field, therefore no inductive heating.
I spend most days at work designing out remedial details for damaged truss and Metal web joists. One of the most common issues we see is plumbers and electricians drilling through structural members to feed cables and pipes. Worth adding this one to your list of common mistakes.
I've been told that the reason solder is not used in house wiring is that it would let go in a fire, with very dangerous results. By the way, Wagos have made it to the USA. I find them very useful on the test bench because it is so easy to make a good connection and then undo it non-destructively.
This is why I don't like the tamper-proof/non-serviceable multi-socket Extension leads as these often use solder joints (to stop people re-purposing them I guess?) I had one recently in a school I work at (in the UK) where I took it out of service because the outer sheath had escaped the cord grip and it had an intermittent supply of power to the sockets. Out of curiosity, I broke it apart just to see how it had failed and it looked as if it had been getting a bit hot as the live connection was barely still connected. In the bin that went. The problem is, where it came from, the room (a faculty Staff room to be more specific) doesn't have many wall sockets so Staff have been using these extension leads where they want to plug in more devices. The other problem is that we have Staff who aren't particular about what they will plug into one extension lead ranging from any one or more of Fridges, Toasters, Kettles & Fan Heaters!
Two other reasons for not putting soldered wires under screws. It's too soft, and will quickly work loose. If/when it does, and a significant current is drawn it will quickly heat up and melt. In an extreme case it will arc and then actually burn, very, very hot!
I remember, many moons ago, when we had a call out to house where the little girl had got a shock. To our utter disbelief, the DIY clown had wired the lighting circuit, on the surface, with the very old purple fabric twin flex cable with uninsulated staples to the wall and ceiling, even the excess cable too!! The little girl got the shock from a live staple near the switch!! I've also come across a whole house wired in bell wire! Had another occasion where I went to help another spark in the middle of trying to rewire a house. I couldn't believe the state of the place, the other spark John was trying to get under the floor in the lounge. RUG nailed to floor, then Lino, then 8x4 board nailed and then tongue and grooved floor boards-different from the norm, in that the boards were grooved female both edges and the tongue was a METAL strip between them!! Sorry to say I left when the woman complained about the mess!! Gave up on house bashing years ago. Good luck you lot!
4:43 Here in Germany daisy-chaining of extension leads with multiple sockets is forbidden. People do it anyways. Problem in my opinion is less the overloading (although many extension leads are only rated for 10A/2300W), because that should trip the breaker. More critical than overloading is the additional connections with their contact resistances. The connections heating up is one issue, but what could be critical is the added resistance also in the PE wire, in worst case the RCD might not trip. But to be honest: I have daisychained one extension, but I am the only one using the plugs and I only have chargers and laptop power supply on it, so we are talking of maybe 150-200W in worst case.
What I'm missing with the screw on plug is a longer earth wire. I've been taught in school that the earth wire should be a bit longer than the live and neutral. That way, in case the live or neutral pop out, the device is at least still grounded.
thats why the earth pin is at the top and theres a space by the earth pin terminal for the earth wire to coil around a bit, so it can be a bit longer and the extra length fits in that space.
@@ge2719 In Schuko plugs, at least the ones from the last 10 years or so, the terminal block for the PE wire is about 5-8mm closer to the strain relief than the hot and neutral. -so basically idiot proof- oh wait, had to strike this, too many people with "special thinking strategies"
The wound up extention could also apply when people are using their vacuum cleaner with the cable wound up inside, not fully pulled out(like a Henry type vacuum). I used to service vacuum cleaners for a cleaning company as an apprentice and we regularly replaced the flex cable inside the vacuum cleaners. The cable had melted together the outer layer inside the coil causing the cable to not be fully deployed. This of course caused a further issue with further melting. Fortunately we never had any fires, but cleaners would complain the cable could not be pulled out properly. We would try to educate the cleaners to "fully pull out the cord" when using the vacuum.
Thanks for the excellent video, I learnt more than I expected from this 👍 I’m interested to know, if you spur a socket off of another socket by dropping your twin & earth down behind a plasterboard wall, what’s the best way to secure that cable when you don’t really have access inside the wall?
That's the assumption that can kill you. Same sort of thing happened a few years ago in Sheffield UK, result 6 dead people. They'd been told what was wrong but reasoned 'it's still working therefore what does he know?' I still see the same faults/attitude daily not only from others but even from the surviving relatives. I despair sometimes, I really do.
How can you overload an extension lead (DIY mistake 4)? They are all 13A fused. Even if you daisy chained 20 they are all running through a 13A fuse at the plug which is protecting the whole chain. Is this not exactly the same as a fused 13A spur; which is why you can run an unlimited amount of sockets off a 13A FCU?
If the extension cords in the UK are this way, overloading might not be a problem. However here in Germany circuits have 16A fuses and the cheapo extension cords with multiple sockets are usually rated for 10A (pure extensions cables are however rated for 16A). Then the problem should be obvious. BTW: the power draw is only half the truth. The additional resistance due to the multiple connections might lead to a too high resistance in the ground/PE wiring. And that might lead to your RCD not tripping.
In the UK socket circuits are rated at 16A radial, 20A radial and most commonly at 32A ring circuit Every plug has its own fuse rated for the appliance as well as the breaker protecting the individual circuits in the main fuse board (consumer unit) . The maximum any UK plug fuse can be rated at is 13A. So regardless of how many cheap multipoint extensions leads are plugged in, they can never draw more than 13A because they are all going through a single 13A fused plug. Some extension leads are only rated at 10A but these would have a 10A fuse in the plug and therefore blow the 10A fuse in the plug. I take your point about the higher loop impedance from extending a circuit using an extension lead, though I think this is probably more of a problem for the breaker rather than the RCD, however the same could be said about a single garden extension lead that has say a long 30m cable. He doesn’t mention those and your average multipoint extension lead is only 2 or 3m long.
I have often wondered the same thing. The first plug has a 13A fuse so it protects its cable and sets a maximum current. I can see that in USA there is no fused plug, but UK is different.
There is no issue. Like you say it is IMPOSSIBLE to overload the device as it's got a fuse rated for the sockets. However I am aware some people say that the earth connection can become a higher resistance over multiple connections, if you're on an RCD circuit it is very meh. Personally I've no issue at all with daisy chaining.
We discussed the problem of unwound extension leads years ago at BT. As the two conductors are side by side, the current magnetic effects should cancel. It is the resistance of the cable that matters with so much cable in a confined space: Recall that the heat produced is proportional to both the current squared and the resistance.
If you fuse down to 13Amp from a 32Amp ring, with a fused spur, can you have sockets wired on 1.5mm twin&earth (after the fuse?) 1.5mm is good for 15Amp, or even 18Amp, for a short time. So with the 13Amp fuse protecting the 1.5mm cable, it should in theory be fine? I know that you will always do it in 2.5mm , but it should be ok on 1.5mm.
The VDE code here in Germany makes distinct requirements for cross-section of cables, based on length (voltage drop) and installation (in isolated dry wall, in a channel, multiple cables combined, so basically heat dissipation). For a normal household installation, 1.5mm² can be fused with 16A, although more and more 1.5mm² are only fused with 10A (13A are more expensive than 10 and 16A) or they use 2.5mm² for 16A circuits.
What about replacing a plug fuse with correct rating. All Plugs have 13 Amp stamped on them but lots of equipment have 3 or 5 amps fitted. People automatically will fit a 13amp as whats on plug if blown as label on fuse sometimes illegable
These fuses in plugs are a relic of the past, irrelevant in the era of MCBs (and RCBOs). Their purpose was to protect wires in your walls in the absence of proper circuit breakers in the consumer unit - a pointless and annoying feature these days (it is much easier to just flip MCB back on, rather than replacing the flimsy fuse in the plug)
@@lelllooooo Mate if it was a perfect world I'd agree but for instance my next door neighbour has a 1930s house with a 1970s fusebox. Her husband tried to pull a bayonet bulb from the fitting and cut his hand open because he didn't know how to remove it and it shattered! It was probably still switched on knowing him.
Fuses in plugs primarily protect the flexible cable, and possibly the appliance. They categorically do NOT and never have protected the ‘cable in the wall’
@@lelllooooo Plug fuses serve a completely different purpose than either MCBs or RCBOs. No one can replace the other. (In particular, RCBOs are electrical-shock-prevention devices, while MCBs and plug fuses are actually both fire-prevention devices (addressing two different risk scenarios). The two different categories of device work very differently and are basically completely unrelated and independent of each other.)
@lelllooooo As per other comments they are still relevant. And in the UK where mains power is commonly distributed using ring circuits, the ring may be protected by a 32A MCB or RCBO but the appliance still has its own protection fuse in the plug generally at 3, 5, or 13A.
Plenty of solar panel fires where the installation was carried out by professional electricians. Plenty of factory fires put down to electrical faults , that's not an installation done by DIY. As an electronic engineer , I have seen many machine tools damaged by electricians who think they are qualified to work on anything from a torch to a nuclear power station.
As a professional, I have stuffed up. No one is perfect. The professional makes far fewer mistakes, because of the long training and continuous learning of the day work. Unfortunately there are some who know better, but take short cuts at every turn, not good for the trade.
@@rodbickeNo. He is criticising electricians, not professionals. Specifically electricians. Electricians that think they are experts Electricians should not be making safety critical mistakes. It is not acceptable to make safety critical mistakes and say "Oh it happens". That is not good enough.
@@deang5622 Electricians can be particularly sanctimonious about their business, but nothing like as bad as a gas fitter. By taking the cover off a gas boiler they will tell you that a small child will die. They will selectively quote the gas safe code and infer that you will end up in jail just by thinking about hooking up your own gas cooker instead of having a trained "engineer" spend 30 seconds attaching a bayonet fitting and charging you a callout fee and 1hr (min) labour. I once tried using one of their forums but got shutdown because I wasn't in the trade. Never mind that I was actually trying to tell one of their trade people that the fix to their problem was not the main PCB swap they tried, and charged a customer for, but a simple sensor replacement. Using the title "professional" just means you are charging money, not that you are any good at your job.
The reason that a wound up coil of wire is not because it creates an inductor. I've heard this myth many times before. The actual reason is pretty simple: an unwound coil simply has a lot more surface area to dissipate away the heat. When it's coiled up, it traps all the heat generated inside of the coil and has nowhere to go except for the minimal surface area that's exposed to the air. This increases the temperate of the conductors inside the coil, since they're effectively insulated, while, at the same time, being heated by their surroundings. There are simply fewer routes for the heat to escape.
You beat me to it! Yes I've also seen that myth about induction before, apart from anything else as the current flows through both live conductors but in opposite directions the magnetic fields cancel.
Interesting to see extension cables where the reel is not completely unwound and the coils welded together by the heat. Actually magnetic fields don’t completely cancel out. To trace a cable which is concealed I use a tele coil with audio amp and draw some current on the cable. Preferably an apple charger generates a nice tone.
I got a question! I live in Italy and I am currently studying Mechatronics, and I love working with electric and electronics, so I decided to re-make my cellar for working down there, and I had to re-make the electrical system, for having a better one. So I got cables of 1.5mmq that should reach into my cellar, and for my life saver i wanted a 2.5mmq cables, so I just used a mammut for changing the diameter. Now I got cables of 2.5mmq going insde there, and I was wondering: will my outlets work fine? I got 16Ampere one, and each of it there are 2.5mmq cables that are giving the power inside of them. I excuse myself for my bad english!
I had to do a lot of electrical work on my house and i took the time to search out quality sockets and sundries. I also made good any poor quality wiring i saw and replaced the choc-block with proper junction boxes. When tightening connectors with a screw driver, nip them up and then again a day later. You'd be surprised how much it will have relaxed in 24 hours.
Maybe I'm misunderstanding but as an electrician in New Zealand, twisting stranded wires together before using a screw terminal/connector is completely standard practise. What is the issue? Also, as other people have mentioned, inductance has nothing to do with the extension lead getting too hot, it's purely because it's not able to let enough heat out into the air.
A number of people also fail to fully pull out the flex lead inside Vacuum Cleaners. As you described for the Extension Lead - It acts exactly the same. Some Vacuums also have thermal cut outs - but cheaper ones are only going to "Go Up in Smoke" & Flames.
Marine engineer here. I could legally run a 500kt ship and have been very trained in electrics, though little practice. However, that said, that last item is news to me and very useful knowledge. If I really thought, my education would have told me, but I didn't and am grateful for the info. In all a very good and practical lesson. Well done and thanks. Do more please. World needs people like you.
Nice to know as a diyer I've not made any of these mistakes. I even have my own live tester beeper. A note on the last one, some extension reels only use the trip/reset on 2 of the four plugs, well mine does anyways(could just be broken), my kid used a 2kw heater on the wrong socket. It didn't trip, nearly caught fire and also melted the wall socket the reel was plugged into! In the other 2 it trips very easily with the heater unless fully unwound.
I have seen extension leads with layers of cable melted together into solid lumps due to overloading and not being unwound enough (in a stage lighting gig where the licenced electrician spent the show patching blown circuits - at what cost the show keeps going on?)
Got called to a drive through sign not working. Has been installed for over a year. The underground was compromised and decommisioned. The mains feeding the first drive through sign (before it looped off) was an extension lead with the ends cust off instead of proper cable.
One interesting thin my Electrical pal showed me, is get and uncoiled roll of twin and earth, make all three wires at the drum end accessible and connect any ONE of the wires to a 240 volt supply, Then put your neon tester or Avo meter on any wire at the roll end and it will show power this is inductance another reason to uncoil and drums of cable.
07:55 DIY mistake 8: apart from the connection problem with over- and undertightening the other issue you glanced over is, that you can't use fine-stranded wire without a ferrule in such a screw connector. You can only skip the ferrule if you use spring-loaded connectors such as a wago, or some wirenut application. (Technically there are also screw connectors that work with fine-stranded wire but these involve parallel plates making the contact and you just use the screw to tighten the plates against each other and the wire in between those plates.) Additionally, the strands are extending to the other side which is a risk of electric shocks. Not a electrician speaking here with english as a secondary language so some terms might not be correct.
Lighting circuit in bell wire, I found one upstairs lighting circuit wired in telephone cable. My friend brought a house and asked me to have a look as the lights kept blowing out
I wanted some two fluorescent lights fitting in my shed years ago and didn’t know how to wire them. My dad suggested going to one of his neighbours who was a sparkys mate. He asked what type of fuse box it had and I told him the wired fuse types. He took me in his shed and wound loads of fuse wire around a dolly peg. As he handed it over he said ‘ I don’t know how to wire it but by the time you have used all this, you will have figured it out’. I was absolutely speechless!
Another good and informative video. Thankfully know them all and always over cautious. Often shocked doing PAT at work. Amount of new extension cables where we fail the plugs out the factory and refit or reterminate wires.
Interesting to see how different DIY electrical projects are in the UK versus in the U.S. In the UK seems most of it is about messing around with plugs and cords, which really isn’t a thing here. I guess that’s because of the need to deal with the fused plugs etc. Here, I’m running house wire, installing receptacles and lights and the associated junction boxes, and new load centers.
I’m a retired industrial electrician, here in the US and find it interesting the differences between your electrical wiring and ours, residential wiring here is240/120 vac @60 hz , the vast majority of residential outlets here are 15 or 20 amp 120 vac large loads stoves, air conditioning, … are 240 vac single phase. In some areas metal conduit is required on residential wiring. I can not tell you how many times I’ve told people to unroll the extension cords, I’ve actually seen a heavy duty cord melt no fire or smoke just a melted extension cord
Kk, so about 20-22 years ago now I was replacing/ capping off a wall light, I had removed the light from the wall and detached the wires. I then proceeded to join the bare cables together, at which point my hand and arm became "locked" in place and it felt twice its normal size with the worst case of pins and needles I've ever experienced! Yes I'd forgotten to turn off the power! After a second or two I managed to pull myself off the cables and after taking a minute or two to recover I went and turned off the mains before finishing the job. I felt a bit funny for a couple of hours after but no long lasting affects as far as I can tell! Is it normal for one's eye to constantly twitch!? 😉🤣
We had an immersion heater that had been wired in the house with 1mm cable. Fortunately we never used it as the boiler provided the hot water. I was only discovered when we had a board update.
One of the craziest domestic instal horrors I found was figure 8 VIR with nails through the centre as clipping. Some of the nails had arc marks either side and the (Wylex off course) rewirable fuse carriers in the CU were so spattered with vaporised copper that they conducted enough without any wire to still show live on a high impedance tester.
Another video you could make it on a DB and annual checks on them, I had solar system installed a few years ago and found that after the 1st year, when i inspected all the CB , i found a number of the screws loose on the CB. I also check the Neutral bar, for loose screws/loose wire connections.
A useful video showing your experience thank you, sadly I've seen most of those from electricians as well, including having my oven nearly go up in flames due to a loose connection and leaving live cables hanging from the ceilings (that hurt). Concerning the failure mode from an extension lead, I thought that's due to the cable not being able to shed the heat due to being wound up. I quickly calculated (so sorry if there's a mistake) that the inductive losses from that situation will be along the realms of 20W, (I think the inductor will be about 4mH), assuming that's a 25m 1.5mm^2 extension lead the resistive losses will be around 80W. (Quite happy to learn and be corrected, I mean this is in an educational learning sense not the standard YT comment way :) ). The other thing I've always done is to make sure the tester works before I rely on it to show a null result, but I use a multimeter, I don't know whether the tester you suggest has a built in check for itself.
Alas some of the pro's are making the same or even worse mistakes. In our house I found multiple live wires being exposed behind ceiling lamp covers. The electrician apparently didn't bother to terminate them properly and used some electrical tape instead which degraded over time which is now a serious risk (both fire and shock hazard I would reckon). Of course I replaced them as soon as I found out by WAGO's.
The wire nuts can be a good connection if you pretwist the wires and if your going to solid to strand push the stranded in first than the copper than twist together. Enough practice you get used to it i prefer copper crimps and nylon caps (Buchanan and the 4 point crimp tool)but am coming around to wagos
I’ve actually seen an extension reel that was left wound up start smoking and all that was drawing current was a 70s/80s stereo system using Gigi separates.
I did the twisting solid, and stranded wires and swapped colors, and also didn't always clamp. Thankfully no issues. It's just double work, cause now I'm re-wiring everything. :)
It is still amazing that some sparkys don't understand maximum demand and how to calculate and size installations. Also how to derate or size MCB's for cables that pass through insulation, especially nowadays with the amount of insulation that is in newer builds.
To question and maybe add to point 9, is NOT stripping the cables back far enough so that when they're screwed into a plug or RCBO etc, the screw is not making proper contact with the copper, and is more on the insulation/sleeving? Seen this on another channel but wasn't totally sure why, I'd guess potential arcing?
Arcing is one possibility. More typical is that at that back of a socket, a ring circuit is broken somewhere by one of the live, neutral or earth conductors not forming a ring. Everything appears correct - plug something in and it works, even a basic socket tester - but the cable resistance to any point in the ring is increased because there is only a single current path instead of two. That can result in overheating of cables in a heavily loaded circuit.
The problem here is one of increased contact resistance. Many decades ago an entire factory burned down and it was because a single screw in a terminal had been tightened up and was partly on the copper conductor and partly on the insulation.
Is the ‘overloading of extension leads’ a thing as the overall daisy chain cannot exceed 13A as the fuse in the first plug top in the chain wins. Discuss ;-) . Assume for sake of argument it is all done neatly and no coiled up extension leads say
As long as the fuse in each plug is correctly rated for the cable, then there isn't a problem. So you could have a 10 amp lead with a 10 amp fixed plug connected to a 5 amp lead with a 5 amp piug and then back up to a 10 amp lead with 10 amp plug. The maximum current the chained extension leads can handle is set by the rating of the lowest cable. In this case it is 5 amps. You might possibly run into a problem with using very many daisy chained cables because of the voltage drop along the cable and that could potentially lead to misoperation of the appliance connected at the load end.
You should see the work of many Australian electricians. My house roof cavity is covered with crisscrossed power cables for lights and power points. None of the cables are marked, there were bare wires at junctions, breakers in the distribution board are not labelled. All done by qualified electricians and all certified by a building inspector when I purchased the house.
Thanks for some great tips. Thankfully, I was already aware of them although the coiled cable was a quite scary. When removing ceilings on my old house I found "rewired" lighting meant, in some places, a few twisted wires with a bit of insulating tape wrapped round them... 😲
Hi Jordan, old school of wiring a 13amp plug (or any plug infact) is that It should be able to survive a cable pull test. i.e on pulling the cable (with a failed restraint) the live cable should be the the first to be pulled from its terminal. followed by the neutral and finally the protective earth lead. Hence the differential lengths of the terminal wires. There should be enough room in the plug top to accomadate the extra length of the protective earth wire. 😀
One thing common in bodge jobs especially around surveillance cameras is using Ethernet cables for power by directly wiring a few cores of the Ethernet cable to either a DC power supply or even mains voltage. The proper way to supply power using an Ethernet cable is to use a PoE injector / switch with a PoE capable device.
And that works because PoE typically uses 48 Volts, and so the current flow (which is what drives heat dissipation) is only a quarter of that used with a 12 volt device for the same wattage.
Im in the us and wire nuts have never sat right with me. Never liked them. I recently discovered the snap connectors and absolutely love them. I use them everywhere.
The "connect all the reds" things is why for a long time now I arrange wiring so that there is only one unambiguous cable at each outlet. All junctioning is done separetely from the outlets in junctions boxes specifically for the purpose.
I bought a property that had garage strip lights, a switch by the garage doors, and another by the inner house door as change-over switching. Wired with T&E, but one way was bright light, and the other way dim light. Yes it should have been 4 core, but they wired the return through the back box instead- so we got a dim light AND a warm wall.! Surprised it worked actually.
Thanks for taking the time to make a very balanced and non-condescending video like this. You will never stop DIYers so why not give some helpful pointers. I know over the years I have been guilty of some of them for sure. As the saying goes though. "Only a fool learns from his own mistakes."
Very interesting...... especially the coiled extension reel, I had no idea that was dangerous. I had aircon installed in my holiday lodge a couple of years ago. Shortly afterwards we were watching TV when we smelled burning. The aircon unit wasn't hard wired, just plugged into a wall socket. The plug had totally burned through, it had a hole in it. Lucky we were in when it happened. Got the installers out to check things and they said there was no fault, only thing they said was maybe a wire in the plug hadn't been tightened up fully.
If you want to make sure you are doing your job correctly, then you will need a proper test device for that. ⚡Kewtech KT 1780 - amzn.to/43Gglzk
Should also include a link for a proving unit.
It's rather KT63DL
Laughing at soldering??? Are you honestly suggesting the way all electronics is made is wrong ?
i was putting some lights up in friends bathroom and the replacement lights had multi stranded cables i put it into the connect and screwed it up pulled and it come out the connector so i though thats not safe, i had a crimping set i brought from lidle and i put like a small tube round the multiple strands crimped that onto there, did twisty 90* bendy thing it didnt come off so i put it into the connector block thingy and screwed it in made sure it didnt come out off that and then put the light to the ceiling, so i think i mad a fairly reasonable effort to make it safe. my general rule of thumb is pull on it and make it look pretty, if it dont brake with a pull and it looks need then its more than likely safe
Prefer the Fluke 150 myself.
Makes me want to do a video about the mistakes I've discovered done by qualified electricians on houses I have purchased over the years!
what proof do you have(visual?)that they were done by qualified electrician?
@@waynethomas3638 e.g. New build house with contract for whole estate done by very large contractor. Etc.
Over-tightening terminals on copper wire is a favourite. Fine for a few years but the excessively squashed conductors can fail and create points of high resistance
EDIT: lol just got to the bit where this was mentioned as a DIY mistake but the pros do it all the time 😅
As with any profession there are good ones and bad ones.
Please share what you have come across, it may save someone’s life.
Fun stuff and so typical mistakes for many DIYers.
But the wound up extention cord running hot, has nothing to do with inductance. It simply the resistance of the cable that cause it to heat up - but being rolled up like a coil, the heat can not escape from the cable very easy (compared to if the cable is rolled out), so the temperature rise quite a lot
As the resistance of copper also goes up by the temperature, this causes it heat up even more in a sort of thermal runaway. This can cause the coil of cable to get toasty, very quickly.
Could not give you two thumbs up.
three thumbs up, the out and return are parallel, so loop area is negligible in this instance , so inductance is negligible, surprised at Jordan for getting that wrong.
Right, and I would like to add that, even if there were a significant inductance (which is not there because the magnetic fields due to the two opposite currents cancel almost perfectly) it would not lead to any power dissipation, only to a lossless voltage drop. It is only the resistive part of the impedance that leads to power dissipation and Joule heating. I do not know why this incorrect belief about the hypothetical inductance and even more hypothetical associated power dissipation of coiled cables consisting of two conductors with opposite currents is so common: I heard it for the first time in high school when I was working part time for a local tv station: a technician from.a local tv production company told me that power cords for halogen lights should not be wound in operation motivating the recommendation with the incorrect inductance argument.
waiting for his reply on this.. haha. ironic how the video is specifically about making mistakes.. lol
Thanks for the clarification! That does make sense 👍
Extension leads - Inductance is not the problem, it's the resistance that creates heat. Cable is rated for a situation where air can circulate around it. Winding it onto a reel adds insultation so the copper temperature rises.
Agreed. Inductance cannot play a role, as you have two coils parallel (two in which current flows, the earth is an open circuit on the end, if the appliance has no earth leakage), and the current flowing in them is always opposite , so the magnetic fields of the two cancel out. Also, inductance does not build up, it is a property of a configuration of wires (large for a coil, very low, e.g., for a twisted pair). What is building up is heat, no matter how it was created.
In AC, inductance *is* resistance.
No - inductance stores energy, it does not dissipate it as heat.
Heat is produced . How does not matter .
Sort of....
Most of the heating in a rolled up extension is caused by the fact you just made a great big electromagnetic coil.
One other thing not mentioned, but something I've not seen done in a fair number of outdoor DIY cabling setups are Drip Loops. Instead you tend to see cables running straight down a wall, right into a junction box with nowhere for the water to go!
I've seen the same done by professional CCTV installers recently. Cameras had gone out. I checked the weatherproof enclosure, unscrewed the cover and about a litre of water poured out. All cables were top-entry, no drain hole, system had worked until water got up to the level of the power supply for the network switch.
Also not-so-professional cable contractors (I won't name names but let's just call them the S*** Wiring Guys) running Ethernet feeds into the tops of Wiska 308s or through drilled-out holes in the rear. As they fail the cables just get jelly-crimped now as if the jack is replaced it just rots again.
"It's IP44, what can go wrong?" 😆
Exactly. I'm a DIYer but I was awake in class when the teacher told us about gravity. I installed a cable in my loft that goes downwards to a junction box but does a wide 'U' before rising up to enter from below. A little bit of thought goes a long way.
I did small drip loops when I put strip lights up in my garage and occasionally wonder if I'll ever snag something on them, lol
The heat produced in a wound up extension lead is NOT caused by induction. It is caused by conductor resistance and lack of cooling.
Exactly!
Bifilar coils like this cancel out the magnetic field nearly completely.
Not knowing about reduction Factor on stacked cables and it's danger is a typical DIY mistake.
Sometimes making fun of others can backfire.
To expand on these accurate comments by op & @AzrethK9. Yes the coil is definitely Bifilar and therefore a non-inductive coil for this purpose (basically the magnetic field of the neutral cancels out the live, why you can't use clamp meters on power cords). Additionally self-induction is not a method of energy dissipation, it is a form of energy storage. If the coil was inductive the energy world be stored in the magnetic field and released later in the AC cycle. This why PFC devices are called for on inductive loads, they don't affect your real power consumption, just the power factor.
What this is, is an example of a hazard caused by bundling many (slightly resistive) conductors together and there being nowhere for the heat to go. Think of it like wrapping the inner wire in a blanket, and an electric blanket at that. This same hazard would occur if there were many separate cables all carrying this current, this is a hazard electricians should understand.
I think this myth may come from two places, people knowing a coil can be inductive, assuming it is because they don't know what an inductor is; and then assuming that one thing they now see is the cause, ignoring the obvious real cause they should already know about.
The other possibility is people are thinking about induction hobs, which is a whole different situation, firstly they use an inductive coil and secondary (pun intended) there is a pan to act as the other, shorted, winding.
One cat we had used this to good effect - it would curl itself up and go to sleep on a coiled extension lead feeding a heater.
Exactly. Even if it wouldn't be bifilar, the number of winds and the low frequency would lead to no real inductive effect.
I'm in my 50's and did a 5 year apprenticeship as an Electronics Technician when I left school. I then became good friends with an Electrician who over the years taught me a lot about household electrical wiring etc. As a result I feel that I'm relatively competent as a DIYer and myself have seem some hacks that were so dangerous I physically shuddered at them. Every bit of work I've ever done on my house electrics, I have an electrician come out and check it. When I built my workshop in the garden 20' x 10', I fitted a 20 socket ring main and 12 light ring. I ran the Armour cable to the CU and had an electrician come check it and connect it up. He said he had no qualms with connecting it and certifying it as the job was good. My point isn't to "big up" my skills and knowledge, but to point out that not all DIYers are terrible, some of us actually go out of our way to make sure we do a good job because we realise that our lives and the lives of our families are very much on the line.
Indeed so. I'm also an electronics engineer and would never make any of the DIY mistakes mentioned here. I also know that it is not inductance that causes a rolled up extension lead to get hot! Unfortunately Part P has turned us DIYers into criminals and, by making the relevant standards inaccessible to non qualified persons made it far more difficult for those of us trying to do a decent job to do so.
The issue for you, that today, some of the work you did is considered _notifiable_ and by law, the Building Control department of the local council has to be notified.
Even if you are competent as a DIYer, you still have to notify the Building Control and they will tell you what certification requirements are needed.
And as you don't hold any formal qualifications, and no membership of NICEIC or NAPIT, then they will require that a qualified electrician inspect and sign it off as being compliant to the wiring regs.
So I think it is important to not send out a message that anyone can just go along and do their own electrical DIY and get an electrician to sign it off.
There is more to it than that.
@@John_LNo, it is not true that Part P has turned people into criminals.
I have repeatedly seen statements made by even electricians that say people can't do their own electrics.
That is not what Part P of the building regs says. Part P says that the work has to be done to compliance of the wiring regs, and be certified by somebody competent and it talks about notification to the building control department.
@@deang5622 This is true but by making the said wiring regs only available to certified personnel the effect is to make it nearly impossible for the conscientious DIYer to do a compliant job. And the DIYer is criminalised unless his work is inspected, even if it is not notifiable work. The practical effect is indeed that the DIYer cannot do his own electrics, no matter how competent he is.
@deang5622 yes but you obviously missed the part where I said it was inspected and checked/tested by a qualified person who then issued the appropriate paperwork. the work I did on my workshop was done back in 2011and as I said, I had an electrician come out to connect it to the CU, I left all the socket fronts off and the lighting covers on the flourescents off so he could see the job I had done and also marked out my cable runs that are behind the OSB that lines the inside, I also have a couple of covers that give easy access to some of the areas where the cable runs incase I need to do any work on it. He was happy enough to sign off on it and to connect it to the house CU. I ran the Armour Cable and routed it to the CU in the garage and again after testing it he was happy to sign off and complimented me on a good job. The result is, I have an ele tri ally safe workshop that has been in use now for 13 years with zero issues (except a small leak in the roof I just had to fix🙄). I have also had another electrical inspection about 2 years ago and they checked the workshop because its connected to the household CU so included it as partnof the house and again had a clean bill of health. Based on all this, why am I breaking the law? Yes I did the work, but didn't make the final connection and it was all tested by a qualified person 🤷
Another vital step for #7: Check your circuit testing device for proper operation before you rely on it....
Yep, it doesn't really have to be a very expensive device either, but testing that it shows a circuit before turning off the power at the distribution board and the looking for the difference is really important. Even when having done this I do have the slightly (bad) habit of intentionally bridging live and neutral because if there's a pop and a circuit breaker kicks in, I'd rather that it do this when I expect it!
Strickly, you should also check your tester immediately AFTER checking the circuit - to ensure that the tester didn't fail JUST BEFORE,or during) your test ! Pro's will have some independant voltage souce -or use knowingly energised circuit.
@@tridentmusic5570 You are right, but I haven't seen anybody doing that, except the guys who work in secondary substations. In household installations it is more common to create an intentional shortcut after testing just to be on the safe side. At least that's the case for Germany.
Cheers
Andreas
@@andreasbentz6106 Agreed.
Coiled extension has current running in opposite directions (hot ("live") out, neutral back) so induction is cancelled out.
It's simply that with enough current the cable heats and because it's coiled the heat isn't dissipated as it would be on an uncoiled line.
The cord is not about induction but simply resistance. When it is wound up it cannot dissipate heat and cool. Once it heats up the resistance increases and it heats even more.
All those thermal protections, as well as fuses and circuit breakers are in case an overload happens. They are not some permission to load as much you can and rely on them to cut.
Absolutely correct! At any point in time the current in the L and N conductors will be flowing in opposite directions and are physically very close together so the magnetic fields cancel.
I was very suprised he made that mistake .
The resistive heating is an issue also, if wire is heat insulated. Adding heat insulation to a wall or ceiling without remaking electric installation may be fire hazard.
Even more important in boat or camper. Low voltage cabling uses high current, and hiding a 1,5 mm2 wire inside good foam insulation and using it just with 120W may be enough to cause a fire. With battery a shorcut ends up to red hot wires very quickly, and insulation can melt and cause short circuit.
@@callumcurtis15 Yes! Especially when he's criticising DIY installations from an expert position - Physician, heal thyself!
@@stpeter7432kind of true, but only at low frequencies. I know I'm nit picking.
Another common mistake is pushing the wire too far into the terminal so that the screw is tightened onto the outer insulation of the wire rather than the copper, thus no connection. Particularly bad if done to the earth.
I get cable pulled from domestic kitchens being refitted and this is probably the most common issue after terminal blocks wrapped in insulation tape.
As the legendary oil rig fire fighter Red Adair said “If you think that hiring professionals is expensive, try hiring amateurs.”
Very, very true - in many industries.
Love it. I am going to use that more with my Senior Managers in Health Care...
Red Adair in a rare moment off from dancing with Ginger Rogers.
Err how can you hire an amateur; only means somebody isn't be paid!!!!
@grahamheath3799 there's always one.
Great video Jordan. As a DIYer I think the advice you're giving is spot on. Discovered the coiled extension risk the hard way as a kid in the 80s (those were the days!). I think most competent DIYers, and professionals are already aware of these points but make mistakes out of haste, lack of the right tools to hand, or a an optimistic approach to risk rather than ignorance.
Wow so that was wrong squared. The induction was not the problem on the extension cord
It was simply the thermal resistance of the cable to air.
The heat is the problem. Just don't use coiled extension leads. Why complicate stuff .
As a DIYer, after seeing this, I feel very competent in my work. I use a very old and reliable Fluke multimeter for various tests, would never dream of all the things you've covered here so I must be in the 'safe' zone (although I have electrocuted myself twice but isn't that to be expected, the first time was as a young child with poking wire in a socket🤣).
After visiting my loft, I can say that it's a mess, clearly the electrician wasn't to our standards.
I have a 10 meter EV charger cable which I always unwind regardless how close the car is, just to me, common sense.
The whole plugging extension inti extension doesnt really apply here thats why the fuse exists. its actually quite hard to overload ive tried just out of interest. Now all these are common sense i genuinely dont get how people think any of this is ok. Ive seen people do it and my mind just cant comprehend how they think its safe.
You are missing the fact that 'common sense' is actually rare and becoming rarer, often pushed out of the situation by dumbass ego.
Also 'idiots' are quite willing to bypass fuses because to their mind a blown fuse is because the fuse is faulty, like a blown light etc, therefore they jury-rig a fix because of that perception of 'what do these so-called 'experts' know? It doesn't blow when I fix it . Therefore I know better than them. It's false logic, but ignorance and ego drives them onwards. QED.
For the UK then yea, all plugs have a fuse, but this isn't the case everywhere.
@@jamesfurz7406 no but this video is filmed in the UK for a majority UK audience.
Yes I know I live in the UK my point still stands.
It's not inductance that overheats the extension lead as the fields will cancel from live and neutral carrying currents in opposite directions - it's a lack of thermal conduction to circulating air of which three is none when it's tightly wound.
That implies the cross sectional area of the wire is really under sized then.
@@chrishard7616
It's the right cross section when unwound and in free circulating air. When tightly spooled the I²R loss is too high when concentrated in the small space. You could have a thicker wire to reduce the i²R loss so it doesn't overheat when tightly spoiled but of course a thicker wire wouldn't fit on the same size spool and you'd end up with a much bigger, heavier and more expensive extension reel. These things are always compromises. It will work at 13A when unspooled and perhaps only 4A when spooled (continuously) or short periods at 13A to limit temperature rise, perhaps relying on a thermal cut out switch.
Mate it is the heat that causes it to heat up! period.
I’m a diy enthusiast and became one so many years ago because of what I saw ‘professionals’ do. Poor quality of work was the main reason but also the cost. Over 40 years I have become a jack of all trades, who has high standards way above what some contractors have. Just look at the quality of work put into new builds…. Shocking.
Good call out with the coiled-up extension lead. That is something I don't see enough people talk about, to be honest. (As others have pointed out, it's not actually about induction, it's actually just about not having enough airflow to properly cool the wire, but the main point is still a good one.) And yeah, you had a pretty nice one there with a thermal cutout and everything, but a lot of them don't have that. It doesn't even have to be one of the really long ones with their own carrying spool like that one was, just a plain extension wire that somebody has left coiled up in a loop sitting on the ground can get a lot hotter than it's supposed to if a decent amount of power is pulled through it.
And the reason you don't want extra exposed conductors even inside a box is because sure, it works _now_ but then later somebody comes on and moves something around and something falls on one of them or one of them gets pushed into something else and all of a sudden you've got a dangerous short. It's not just about getting things to work right at that moment, it's also about making sure they won't go horribly wrong somewhere down the line, too.
Oh, and with the screw terminals, one other important point, IMHO: *Always tighten them twice.* Screw them down initially, then move the rest of your wires around, get everything properly in place, and get ready to button the whole thing back up, and then go around and _make sure all the screw terminals are still tight._ It's amazing how often they can become loose just from moving stuff around after you've initially tightened them (part of the reason I much prefer other types of connectors like the WAGOs when they're an option).
Hi Jordan, I enjoy your video's but I am not an electrician I only do the basics, one of my biggest electrical pet hates is wrong size fuses in plugs about a month ago we bought an electric hand held food blender only 175 watts but fitted with a 13 amp fuse that to me is a safety issue by the manufacture and against the warranty I swapped the 13 amp fuse for a 3 amp it works fine its just down to basics. I can understand with power tools a 400 watt drill will be fitted with a 5 amp and not a 3 amp because of the start up of a motor.
Great video thanks for showing Take care
The fuse protects the wire not the power draw of the device. Although you may have a low wattage it may well have a higher inrush current and that could blow the fuse. Unlikely with the figures you have given and fuses have a degree of inrush allowance.
@@davideyres955 Hi David, thank for your reply, but would a 13 amp fuse blow on some thing with very little power if there is a fault on the appliance the cable is only 0.5mm twin flat flex, I am not electrician but I was told to use the correct fuse for the wattage of the appliance, once again thanks for your info
@@shaun30-3-mg9zs The fuse should be sized to a maximum of what the power cable of the device can handle, or 13A, whichever is smaller. Most appliances have cords which can handle 13A, even if the device itself is never intended to draw that much, so a 13A fuse in the plug is fine (it will still trip before anything gets hot enough to cause damage/fire). However, if your device has a cord with 0.5mm^2 conductors, then that probably shouldn't go over 5A or so, so yeah, a 13A fuse is arguably wrong in that case.
@@foogod4237 Thank you very much for your reply. just concerned
Electricians trade is like no other for slagging off everybody else's work except their own.....
This happens in all blue-collar jobs.
Doesn't happen in professional services, eg medical or legal.
Probably indicative of education.
Jordan loves to slag off the customers (DIYers)😂
There is some reason for it I'd argue, especially when electrics are one of the most dangerous things one can play with in a house, alongside gas. It has to be done right, there's no room for corner cutting or mistakes.
@@chuckmaddison2924absolutely does happen in medicine and legal. Humans are humans.
I've employed several 'qualified' electrical contractors and had some really shoddy work completed. Be carefull not to employ an electrician that doesn't know what he or she is doing.
Back to school for Jordan with the "induction" heating... If it was wound around a metal core with a load more current at a frequency in the kHz, then maybe...... Boring old resistance heating I'm afraid. Do your media team not fact check?
Well, the explanation was not quite right, but the actual issue and main point is still entirely valid, so I'm still glad he mentioned it, at least. Coiled up extension leads can get a lot hotter than they're supposed to (really just because of lack of airflow for cooling), and that can actually be a real problem in some cases, so you definitely should always uncoil them and separate them if you're pulling any kind of significant power through them...
@@foogod4237 when you say “not quite right”, you mean not even close…… the same outcome does not not justify an incorrect explanation. Especially so when the whole video is berating “DIY” practises in the first place. And even more so when these supposed DIY practices have plenty of precedent of being done by so called “professionals “ in the first place.
There are two different things in this which the video presenter has confused.
1. Induction coil
2. Solenoid
We don't have 1 here, we have 2.
And in the case of 2, we actually have two solenoids interwoven, comprising one turn of line one turn of neutral and this then repeats for the full length of the solenoid.
Both line and neutral coils are wound in the same direction, so both coils will produce a magnetic field each in the same direction if the direction of the current in both coils is in the same direction.
However, as we know, the line and neutral currents are in opposite directions which means the magnetic fields are in opposite directions.
Assuming no earth leakage, then the line and the neutral currents and the same magnitude.
The net effect is the two magnetic fields are equal and opposite and cancel each other out.
So no magnetic field.
It is very common for electricians not to understand much about solenoids other than they create a magnetic field.
I have seen had an argument with a sparky on this channel that tried to argue the inductance was zero and quite firmly stated that the inductance is not related to the physical properties of the coil.
Something seriously going wrong with their education in inductance and solenoids.
But I guess, an electrician trains electricians. So the myths perpetuate.
@@deang5622 Can an inductive or capacitive load shift the current on the return line?
@@deang5622 For future reference:
A) The inductance is independent of the current only as long as the materials forming the magnetic core behave linearly. That means an inductor with an iron core will have a current dependent inductance if said current gets high enough.
B) The inductance for a coiled twin-lead is indeed not higher than for a straight twin-lead of equal length if the distance between conductors is much smaller than the distance between windings. For the extension cable those distances are comparable so I am not sure. This is because the magnetic fields of both conductors cancel and so the different turns cannot affect each other.
C) The inductance ultimately doesn't matter much because inductance doesn't draw real power and create heat. Technically it draws reactive power and that creates more heat in other parts of the wire but realistically that effect should be negligible.
Some of those DIY fails like clipping I've also seen from "professionals" trying to rush a job :)
Very true!
Using snips to remove the outer sheath and cutting into the inner insulators and partly exposing the copper. Not always visible but a real danger for getting a shock.
That’s a good one too!
Yep, it's a very easy thing to do too. I love my proper wire cutters but even these don't work on all cables as well as I'd like.
I had a case where the customer connected a 3 phase motor by himself and did just that. He made accidental cuts into two-phase and neutral insulation. Since there was still air for insulation, it worked.
It had a motor protection breaker on the circuit and it started shutting off regularly (once or twice a week). So he decides to change the circuit breaker, at first it seemed to stay on a little longer, but soon the same pattern. A little later he also replaced the motor, still the same.
When I went there I suspected insulation, but insulation tests with 1000V did seem ok. I still decided to open everything on both sides, to check cable and connections and that's when I noticed these cuts. Fortunately, there was enough cable to cut this section off and do it again. Since then, no problems. He checked that motor connection box dozens of times and me and other guys with electrical backgrounds checked the box also and saw nothing. Cuts in insulation where straight, both halves were kept together so no exposed copper, no moisture and no signs of a short circuit.
7:45, use ferrule crimp ends (shoelace crimp). Not only do you crimp once with your tool, the screw itself will compress the wires against the ferrule and they won't separate or spread out, ensuring a solid connection. I don't know why people don't use them on stranded wire outside the EU. Every time i see one without a crimp, I cringe.
Must admit I like using ferrules - got some a few years ago (with crimp). While not an electrician as a retired electronic engineer I know more than most.
@@apk55 Discovered simple ferrules for flex termination years back.
I need two on the second meter tails i just upgraded (from the insufficiently sized cable the previous diyer did). But I'm not going to buy a tool just to crimp two ferrules!
Professionals work on live boxes. You just have to be mindful. Otherwise you're working in the dark!
@@imaginitivity7853 I crimp hundreds of wires every day since I'm building automation cabinets with PLCs and drives and other stuff, so I really need it, but on installations with solid core, I guess you don't really need it. But my point stands. Multi core wire should be always crimped unless connected to a spring terminal. Push terminals and Screw terminals need the crimp.
Speak for yourself, don’t keep denigrating DIYers who know what they are doing and do better than some of the cowboy electricians that are out there.
As a DIY er I’ve improved the appalling wiring (probably done by the builder who built his own house) in our 1970s house. Single ring for an entire 3bed detached house including immersion as a spur off the ring. It had lots of wire nuts and twisted connections! Borrowed neutrals.
I’d just go read BS7671 and the on site guide and do it properly. Added separate radial for the immersion, which is no longer used but it supplies power to the loft for the digital shower and axial fan, I split the single ring into two rings (proper and continuous), re wired the kitchen, garage and boiler house.
They used to stock the IEE wiring regs in WH Smith’s in town, I used to go read and memorise before doing work.
Only thing I’ve lacked over the years is a MFT. But subsequent PIRs (EICR for the youngsters) have shown the installation to be sound including the fixed borrowed neutrals.
Did have reputable a local spark in to change the CU to full RCBO board 14 years ago and recently had spark in to replace the RCBOs and main switch but kept the enclosure.
Not paying Artisan prices to do something I can do myself to a proper standard!
I guess the problem is they rarely come across good DIY as they assume all good installs are by sparkies and all the poor stuff is by DIY Dave (being a David it’s even more grating).
Frankly there are some horrible wiring bodges I’ve seen and some of the crap jobs I’ve see. In my house done for the sake of speed rather than quality and maintainability are annoying to say the least. 1mm cable for the light that snaps because the copper has work hardened and not enough slack on the cables.
However there are a ton of things I would not know like how to design earthing arrangement on a solar install with UPS functionality that are defo a job for a qualified sparky.
The problem is people like you are probably a rare breed.
I work as an Electrician in Australia and I think the reason DIY is generally frowned upon is because the potential risk involved for one and the propensity for DIY people to think they're ready to tackle certain aspects of the job they aren't prepared for.
On the flip side, if your DIY is up to par, I would assume most electricians will just assume it was professionally done which strengthens their cognitive bias because in their eyes all they see is the DIY fuckups.
Side-note: It's illegal in Australia to work on electricity without being licensed so maybe it's different wherever you guys are from (:
@@cmm287 In the UK, there is quite a lot of DIY work permitted: pretty much anything internal except bathrooms or new circuits from the consumer unit (and anything else can still be done DIY if notified to the council building control and then electrically tested by a professional). Problem is that any work you do must be tested to BS7671 which requires calibrated test equipment that no DIYer is likely to own, and most sparkies won't be interested in testing DIYers work for them.
The irony is, of course, that when was young and irresponsible, I installed an outside light (fused down from a spur on a socket circuit) and tested my own work as best as I could using 40-year old test equipment... couldn't find an earth. I then discovered that the socket spur (professionally installed some years prior) I was using to feed the light was itself spurred from another socket spur (not how it should have been done) and that that the first spur wasn't connected to earth: 2 unearthed sockets. Hence, I, the DIYer was obviously the first person to check my own work with any test equipment whatsoever, and also the one who ended up correcting the fault, only because I was testing my own DIY work, albeit not with the calibrated test equipment I should have been using.
Great stuff.
I've got a Jo Jo extension reel from the late 80s with thermal cut out. Yes, still working fine.
In reality why is there any issue daisy chaining 4 way type extensions, given, in the UK where this is filmed, each plug (including the primary extension) has a 13A max fuse, the most you could pull in the entire circuit is no different to it being on it's own. The fuse will blow and assuming the extension lead is suitably manufactured and tested, there should be no additional risk.
I'm pretty sure that warning been imported from the US...
The issue is that many of them aren't suitably manufactured and tested. People buy stuff online from wherever they can find it cheapest, and that results in a lot of really poor quality. How easy it is to find a partial earth pin in plugs for all kinds of things these days is sort of scary, & switched multi-gang extensions can be particularly gnarly with switches not rated for the mains or being spongy & audibly arcing. The fuse may eventually blow, but that doesn't mean you won't get heat build-up and scorching before it happens.
@@nightcatarts fair point but if it’s cheap tatt then a single one is just as likely to go up in flames.
@@craigmck7271 Very true, but that risk increases if the cheap one is first in a chain.
13 amp fuse won't blow till you pull 26 amps or so through it, though. And the ring main will have a 30 amp circuit breaker. It's quite possible to get wiring running hot without the fuse blowing. If that wiring is enclosed somewhere - say run under furniture, tucked behind curtains - then the heat can't escape, and can build up to 'burning down the house' levels.
In our first house I was swapping out some ceiling light fixings.
So, I turned off both "Lighting" Fuses at the box.
But, in a bungalow, with full access to the cables in the loft space, I quickly found that the bathroom lighting was hooked into the socket ring. Quickly and sharply.
Learnt an important lesson about other people's work and the value of test equipment that day.
similar situation where i found out the garage lights were running off the kitchen sockets ring.
In my bungalow somebody had wired the garage by stringing an unsupported t&e across the 2' gap from the house, which I managed to twang a couple of times while carrying a ladder. Even better, it was spurred off the socket in the attic that was for the boiler and the garage had a dodgy roof so, in wet weather, it would trip the RCD that fed half the house and the only way to isolate it was to turn the boiler off.
I paid some sparkies £250 to put a separate RCD in for the garage and an armoured cable running under the decking instead of looming over me. Well worth it.
I well remember a case when I was on a Tech Theatre Course back in the Eighties. The theatre was adjoining the old Victorian house, and while the LX had it's own supply, other equipment tended to be run from the house's supply. On this show the whole stage had been painted with size paint and then sealed with Emulsion Glaze (PVA). During the night there had been a leak and the stage was soaked, walking on it would rip up the paint, and that was a key part of the show. So. Every heater we could find was put on stage to try to dry it before the afternoon Matinee. Couldn't even mop it, it was so soft!
So the extension cable (at full length), got hotter and hotter, then blew the fuse. The Chief LX on the show went to the fuse box and pulled this huge, palm sized ceramic MK fuse out without thinking, and got MK branded into his palm. Nasty!
At least he was able to pull it out. I have seen this things get welded in place
Is the coiled extension lead really an induction problem, or just that the normal amount of resistive heat cannot dissipate? Or a bit of each?
Resistive heating only.
There is no net magnetic field created by a coil of mains cable as there are two currents passing through two coils in opposite directions.
No net magnetic field, therefore no inductive heating.
I spend most days at work designing out remedial details for damaged truss and Metal web joists. One of the most common issues we see is plumbers and electricians drilling through structural members to feed cables and pipes. Worth adding this one to your list of common mistakes.
I've been told that the reason solder is not used in house wiring is that it would let go in a fire, with very dangerous results. By the way, Wagos have made it to the USA. I find them very useful on the test bench because it is so easy to make a good connection and then undo it non-destructively.
This is why I don't like the tamper-proof/non-serviceable multi-socket Extension leads as these often use solder joints (to stop people re-purposing them I guess?)
I had one recently in a school I work at (in the UK) where I took it out of service because the outer sheath had escaped the cord grip and it had an intermittent supply of power to the sockets. Out of curiosity, I broke it apart just to see how it had failed and it looked as if it had been getting a bit hot as the live connection was barely still connected. In the bin that went.
The problem is, where it came from, the room (a faculty Staff room to be more specific) doesn't have many wall sockets so Staff have been using these extension leads where they want to plug in more devices. The other problem is that we have Staff who aren't particular about what they will plug into one extension lead ranging from any one or more of Fridges, Toasters, Kettles & Fan Heaters!
i guess when you're house is burning down, you don't want it burning down a second time :P
Two other reasons for not putting soldered wires under screws. It's too soft, and will quickly work loose. If/when it does, and a significant current is drawn it will quickly heat up and melt. In an extreme case it will arc and then actually burn, very, very hot!
I remember, many moons ago, when we had a call out to house where the little girl had got a shock. To our utter disbelief, the DIY clown had wired the lighting circuit, on the surface, with the very old purple fabric twin flex cable with uninsulated staples to the wall and ceiling, even the excess cable too!! The little girl got the shock from a live staple near the switch!! I've also come across a whole house wired in bell wire! Had another occasion where I went to help another spark in the middle of trying to rewire a house. I couldn't believe the state of the place, the other spark John was trying to get under the floor in the lounge. RUG nailed to floor, then Lino, then 8x4 board nailed and then tongue and grooved floor boards-different from the norm, in that the boards were grooved female both edges and the tongue was a METAL strip between them!! Sorry to say I left when the woman complained about the mess!! Gave up on house bashing years ago. Good luck you lot!
Thanks for the advice on unrolling the extension lead. It had not occured to me. Cheers
Thanks for the good advice. I learned to unwind an extension lead fully. Will do that in future.
4:43 Here in Germany daisy-chaining of extension leads with multiple sockets is forbidden. People do it anyways.
Problem in my opinion is less the overloading (although many extension leads are only rated for 10A/2300W), because that should trip the breaker.
More critical than overloading is the additional connections with their contact resistances. The connections heating up is one issue, but what could be critical is the added resistance also in the PE wire, in worst case the RCD might not trip.
But to be honest: I have daisychained one extension, but I am the only one using the plugs and I only have chargers and laptop power supply on it, so we are talking of maybe 150-200W in worst case.
Interesting about the extension lead, I never knew that. That explains why it cuts out sometimes! Thanks for tips
here in australia and new zealand it is standard to twist wires together and put in a screw connector.
British electricians hate that when they have to isolate sections of a ring main to try to find a fault.
We don't have ring circuits in Australia.
@@robinbennett5994 completely agree. I think we should use wagos
What I'm missing with the screw on plug is a longer earth wire. I've been taught in school that the earth wire should be a bit longer than the live and neutral. That way, in case the live or neutral pop out, the device is at least still grounded.
thats why the earth pin is at the top and theres a space by the earth pin terminal for the earth wire to coil around a bit, so it can be a bit longer and the extra length fits in that space.
@@ge2719 In Schuko plugs, at least the ones from the last 10 years or so, the terminal block for the PE wire is about 5-8mm closer to the strain relief than the hot and neutral. -so basically idiot proof- oh wait, had to strike this, too many people with "special thinking strategies"
I just started doing some DIY electrics around our business. Thanks for this video you have my like!
The wound up extention could also apply when people are using their vacuum cleaner with the cable wound up inside, not fully pulled out(like a Henry type vacuum). I used to service vacuum cleaners for a cleaning company as an apprentice and we regularly replaced the flex cable inside the vacuum cleaners. The cable had melted together the outer layer inside the coil causing the cable to not be fully deployed. This of course caused a further issue with further melting. Fortunately we never had any fires, but cleaners would complain the cable could not be pulled out properly. We would try to educate the cleaners to "fully pull out the cord" when using the vacuum.
That’s never happened on a single vacuum I’ve ever encountered.
Thanks for the excellent video, I learnt more than I expected from this 👍
I’m interested to know, if you spur a socket off of another socket by dropping your twin & earth down behind a plasterboard wall, what’s the best way to secure that cable when you don’t really have access inside the wall?
An extension lead will be fused on the plug so surely it’s not possible to overload and start a fire?
the issue is overheating even when the load is within tolerance
Its not overloading, its resistance causing the problem.
Depends on what rating the fuse used.
That's the assumption that can kill you. Same sort of thing happened a few years ago in Sheffield UK, result 6 dead people. They'd been told what was wrong but reasoned 'it's still working therefore what does he know?' I still see the same faults/attitude daily not only from others but even from the surviving relatives. I despair sometimes, I really do.
wrong
How can you overload an extension lead (DIY mistake 4)? They are all 13A fused. Even if you daisy chained 20 they are all running through a 13A fuse at the plug which is protecting the whole chain. Is this not exactly the same as a fused 13A spur; which is why you can run an unlimited amount of sockets off a 13A FCU?
If the extension cords in the UK are this way, overloading might not be a problem. However here in Germany circuits have 16A fuses and the cheapo extension cords with multiple sockets are usually rated for 10A (pure extensions cables are however rated for 16A). Then the problem should be obvious.
BTW: the power draw is only half the truth. The additional resistance due to the multiple connections might lead to a too high resistance in the ground/PE wiring. And that might lead to your RCD not tripping.
In the UK socket circuits are rated at 16A radial, 20A radial and most commonly at 32A ring circuit Every plug has its own fuse rated for the appliance as well as the breaker protecting the individual circuits in the main fuse board (consumer unit) . The maximum any UK plug fuse can be rated at is 13A. So regardless of how many cheap multipoint extensions leads are plugged in, they can never draw more than 13A because they are all going through a single 13A fused plug. Some extension leads are only rated at 10A but these would have a 10A fuse in the plug and therefore blow the 10A fuse in the plug. I take your point about the higher loop impedance from extending a circuit using an extension lead, though I think this is probably more of a problem for the breaker rather than the RCD, however the same could be said about a single garden extension lead that has say a long 30m cable. He doesn’t mention those and your average multipoint extension lead is only 2 or 3m long.
Why is daisy chaining extension leads into each other dangerous, when each one is fused?
I have often wondered the same thing. The first plug has a 13A fuse so it protects its cable and sets a maximum current. I can see that in USA there is no fused plug, but UK is different.
There is no issue. Like you say it is IMPOSSIBLE to overload the device as it's got a fuse rated for the sockets.
However I am aware some people say that the earth connection can become a higher resistance over multiple connections, if you're on an RCD circuit it is very meh. Personally I've no issue at all with daisy chaining.
We discussed the problem of unwound extension leads years ago at BT. As the two conductors are side by side, the current magnetic effects should cancel. It is the resistance of the cable that matters with so much cable in a confined space: Recall that the heat produced is proportional to both the current squared and the resistance.
If you fuse down to 13Amp from a 32Amp ring, with a fused spur, can you have sockets wired on 1.5mm twin&earth (after the fuse?) 1.5mm is good for 15Amp, or even 18Amp, for a short time. So with the 13Amp fuse protecting the 1.5mm cable, it should in theory be fine? I know that you will always do it in 2.5mm , but it should be ok on 1.5mm.
The VDE code here in Germany makes distinct requirements for cross-section of cables, based on length (voltage drop) and installation (in isolated dry wall, in a channel, multiple cables combined, so basically heat dissipation). For a normal household installation, 1.5mm² can be fused with 16A, although more and more 1.5mm² are only fused with 10A (13A are more expensive than 10 and 16A) or they use 2.5mm² for 16A circuits.
What is the intrinsic issue with using otherwise adequately heavy (stranded) cable (flex) for wiring fixed/hard-wired equipment (rather than T&E)?
What about replacing a plug fuse with correct rating. All Plugs have 13 Amp stamped on them but lots of equipment have 3 or 5 amps fitted. People automatically will fit a 13amp as whats on plug if blown as label on fuse sometimes illegable
These fuses in plugs are a relic of the past, irrelevant in the era of MCBs (and RCBOs). Their purpose was to protect wires in your walls in the absence of proper circuit breakers in the consumer unit - a pointless and annoying feature these days (it is much easier to just flip MCB back on, rather than replacing the flimsy fuse in the plug)
@@lelllooooo Mate if it was a perfect world I'd agree but for instance my next door neighbour has a 1930s house with a 1970s fusebox. Her husband tried to pull a bayonet bulb from the fitting and cut his hand open because he didn't know how to remove it and it shattered! It was probably still switched on knowing him.
Fuses in plugs primarily protect the flexible cable, and possibly the appliance. They categorically do NOT and never have protected the ‘cable in the wall’
@@lelllooooo Plug fuses serve a completely different purpose than either MCBs or RCBOs. No one can replace the other.
(In particular, RCBOs are electrical-shock-prevention devices, while MCBs and plug fuses are actually both fire-prevention devices (addressing two different risk scenarios). The two different categories of device work very differently and are basically completely unrelated and independent of each other.)
@lelllooooo As per other comments they are still relevant. And in the UK where mains power is commonly distributed using ring circuits, the ring may be protected by a 32A MCB or RCBO but the appliance still has its own protection fuse in the plug generally at 3, 5, or 13A.
Plenty of solar panel fires where the installation was carried out by professional electricians.
Plenty of factory fires put down to electrical faults , that's not an installation done by DIY.
As an electronic engineer , I have seen many machine tools damaged by electricians who think they are qualified to work on anything from a torch to a nuclear power station.
As a professional, I have stuffed up. No one is perfect. The professional makes far fewer mistakes, because of the long training and continuous learning of the day work. Unfortunately there are some who know better, but take short cuts at every turn, not good for the trade.
@@rodbickeNo. He is criticising electricians, not professionals.
Specifically electricians.
Electricians that think they are experts
Electricians should not be making safety critical mistakes.
It is not acceptable to make safety critical mistakes and say "Oh it happens". That is not good enough.
@@deang5622 Electricians can be particularly sanctimonious about their business, but nothing like as bad as a gas fitter. By taking the cover off a gas boiler they will tell you that a small child will die. They will selectively quote the gas safe code and infer that you will end up in jail just by thinking about hooking up your own gas cooker instead of having a trained "engineer" spend 30 seconds attaching a bayonet fitting and charging you a callout fee and 1hr (min) labour. I once tried using one of their forums but got shutdown because I wasn't in the trade. Never mind that I was actually trying to tell one of their trade people that the fix to their problem was not the main PCB swap they tried, and charged a customer for, but a simple sensor replacement. Using the title "professional" just means you are charging money, not that you are any good at your job.
One reason I will not buy a electric car. Electric will always cause fires no matter how good you are.
The reason that a wound up coil of wire is not because it creates an inductor. I've heard this myth many times before. The actual reason is pretty simple: an unwound coil simply has a lot more surface area to dissipate away the heat. When it's coiled up, it traps all the heat generated inside of the coil and has nowhere to go except for the minimal surface area that's exposed to the air. This increases the temperate of the conductors inside the coil, since they're effectively insulated, while, at the same time, being heated by their surroundings. There are simply fewer routes for the heat to escape.
Thanks 👍
You beat me to it! Yes I've also seen that myth about induction before, apart from anything else as the current flows through both live conductors but in opposite directions the magnetic fields cancel.
Interesting to see extension cables where the reel is not completely unwound and the coils welded together by the heat.
Actually magnetic fields don’t completely cancel out. To trace a cable which is concealed I use a tele coil with audio amp and draw some current on the cable. Preferably an apple charger generates a nice tone.
I got a question! I live in Italy and I am currently studying Mechatronics, and I love working with electric and electronics, so I decided to re-make my cellar for working down there, and I had to re-make the electrical system, for having a better one. So I got cables of 1.5mmq that should reach into my cellar, and for my life saver i wanted a 2.5mmq cables, so I just used a mammut for changing the diameter. Now I got cables of 2.5mmq going insde there, and I was wondering: will my outlets work fine? I got 16Ampere one, and each of it there are 2.5mmq cables that are giving the power inside of them. I excuse myself for my bad english!
I had to do a lot of electrical work on my house and i took the time to search out quality sockets and sundries. I also made good any poor quality wiring i saw and replaced the choc-block with proper junction boxes. When tightening connectors with a screw driver, nip them up and then again a day later. You'd be surprised how much it will have relaxed in 24 hours.
Maybe I'm misunderstanding but as an electrician in New Zealand, twisting stranded wires together before using a screw terminal/connector is completely standard practise. What is the issue? Also, as other people have mentioned, inductance has nothing to do with the extension lead getting too hot, it's purely because it's not able to let enough heat out into the air.
A number of people also fail to fully pull out the flex lead inside Vacuum Cleaners. As you described for the Extension Lead - It acts exactly the same. Some Vacuums also have thermal cut outs - but cheaper ones are only going to "Go Up in Smoke" & Flames.
What about screwing the terminal onto insulation? I see that all the time.
Surprised he missed that one, since they often mention it on the channel when it comes up in fault finding.
It's not induction, just resistive heating
Marine engineer here. I could legally run a 500kt ship and have been very trained in electrics, though little practice. However, that said, that last item is news to me and very useful knowledge. If I really thought, my education would have told me, but I didn't and am grateful for the info. In all a very good and practical lesson. Well done and thanks. Do more please. World needs people like you.
What clips do you recommend for securing cables?
The correct size for the cable!!😃
Nice to know as a diyer I've not made any of these mistakes. I even have my own live tester beeper. A note on the last one, some extension reels only use the trip/reset on 2 of the four plugs, well mine does anyways(could just be broken), my kid used a 2kw heater on the wrong socket. It didn't trip, nearly caught fire and also melted the wall socket the reel was plugged into! In the other 2 it trips very easily with the heater unless fully unwound.
I have seen extension leads with layers of cable melted together into solid lumps due to overloading and not being unwound enough (in a stage lighting gig where the licenced electrician spent the show patching blown circuits - at what cost the show keeps going on?)
Got called to a drive through sign not working. Has been installed for over a year. The underground was compromised and decommisioned. The mains feeding the first drive through sign (before it looped off) was an extension lead with the ends cust off instead of proper cable.
One interesting thin my Electrical pal showed me, is get and uncoiled roll of twin and earth, make all three wires at the drum end accessible and connect any ONE of the wires to a 240 volt supply, Then put your neon tester or Avo meter on any wire at the roll end and it will show power this is inductance another reason to uncoil and drums of cable.
07:55 DIY mistake 8: apart from the connection problem with over- and undertightening the other issue you glanced over is, that you can't use fine-stranded wire without a ferrule in such a screw connector. You can only skip the ferrule if you use spring-loaded connectors such as a wago, or some wirenut application. (Technically there are also screw connectors that work with fine-stranded wire but these involve parallel plates making the contact and you just use the screw to tighten the plates against each other and the wire in between those plates.)
Additionally, the strands are extending to the other side which is a risk of electric shocks.
Not a electrician speaking here with english as a secondary language so some terms might not be correct.
Lighting circuit in bell wire, I found one upstairs lighting circuit wired in telephone cable.
My friend brought a house and asked me to have a look as the lights kept blowing out
So glad to hear you pronounce WAGO correctly, i.e. vargo instead of waygo which so many others do.
I wanted some two fluorescent lights fitting in my shed years ago and didn’t know how to wire them. My dad suggested going to one of his neighbours who was a sparkys mate. He asked what type of fuse box it had and I told him the wired fuse types. He took me in his shed and wound loads of fuse wire around a dolly peg. As he handed it over he said ‘ I don’t know how to wire it but by the time you have used all this, you will have figured it out’. I was absolutely speechless!
As an electrician of over 50 years experience I was taught as an apprentice to twist wires together before screwing into terminals!
Still the procedure in Australia.
pretty sure efixx still show it.
Another good and informative video. Thankfully know them all and always over cautious.
Often shocked doing PAT at work. Amount of new extension cables where we fail the plugs out the factory and refit or reterminate wires.
Interesting to see how different DIY electrical projects are in the UK versus in the U.S. In the UK seems most of it is about messing around with plugs and cords, which really isn’t a thing here. I guess that’s because of the need to deal with the fused plugs etc. Here, I’m running house wire, installing receptacles and lights and the associated junction boxes, and new load centers.
I’m a retired industrial electrician, here in the US and find it interesting the differences between your electrical wiring and ours, residential wiring here is240/120 vac @60 hz , the vast majority of residential outlets here are 15 or 20 amp 120 vac large loads stoves, air conditioning, … are 240 vac single phase. In some areas metal conduit is required on residential wiring.
I can not tell you how many times I’ve told people to unroll the extension cords, I’ve actually seen a heavy duty cord melt no fire or smoke just a melted extension cord
Kk, so about 20-22 years ago now I was replacing/ capping off a wall light, I had removed the light from the wall and detached the wires. I then proceeded to join the bare cables together, at which point my hand and arm became "locked" in place and it felt twice its normal size with the worst case of pins and needles I've ever experienced! Yes I'd forgotten to turn off the power! After a second or two I managed to pull myself off the cables and after taking a minute or two to recover I went and turned off the mains before finishing the job. I felt a bit funny for a couple of hours after but no long lasting affects as far as I can tell!
Is it normal for one's eye to constantly twitch!? 😉🤣
We had an immersion heater that had been wired in the house with 1mm cable. Fortunately we never used it as the boiler provided the hot water. I was only discovered when we had a board update.
One of the craziest domestic instal horrors I found was figure 8 VIR with nails through the centre as clipping. Some of the nails had arc marks either side and the (Wylex off course) rewirable fuse carriers in the CU were so spattered with vaporised copper that they conducted enough without any wire to still show live on a high impedance tester.
Another video you could make it on a DB and annual checks on them, I had solar system installed a few years ago and found that after the 1st year, when i inspected all the CB , i found a number of the screws loose on the CB. I also check the Neutral bar, for loose screws/loose wire connections.
A useful video showing your experience thank you, sadly I've seen most of those from electricians as well, including having my oven nearly go up in flames due to a loose connection and leaving live cables hanging from the ceilings (that hurt). Concerning the failure mode from an extension lead, I thought that's due to the cable not being able to shed the heat due to being wound up. I quickly calculated (so sorry if there's a mistake) that the inductive losses from that situation will be along the realms of 20W, (I think the inductor will be about 4mH), assuming that's a 25m 1.5mm^2 extension lead the resistive losses will be around 80W. (Quite happy to learn and be corrected, I mean this is in an educational learning sense not the standard YT comment way :) ). The other thing I've always done is to make sure the tester works before I rely on it to show a null result, but I use a multimeter, I don't know whether the tester you suggest has a built in check for itself.
Alas some of the pro's are making the same or even worse mistakes. In our house I found multiple live wires being exposed behind ceiling lamp covers. The electrician apparently didn't bother to terminate them properly and used some electrical tape instead which degraded over time which is now a serious risk (both fire and shock hazard I would reckon). Of course I replaced them as soon as I found out by WAGO's.
The wire nuts can be a good connection if you pretwist the wires and if your going to solid to strand push the stranded in first than the copper than twist together. Enough practice you get used to it i prefer copper crimps and nylon caps (Buchanan and the 4 point crimp tool)but am coming around to wagos
Yes, do be careful getting pulled off in the loft, insulation fibres get everywhere.
Why would you ever connect stranded to single conductors?
There would be a fused spare etc
I’ve actually seen an extension reel that was left wound up start smoking and all that was drawing current was a 70s/80s stereo system using Gigi separates.
I did the twisting solid, and stranded wires and swapped colors, and also didn't always clamp. Thankfully no issues. It's just double work, cause now I'm re-wiring everything. :)
It is still amazing that some sparkys don't understand maximum demand and how to calculate and size installations. Also how to derate or size MCB's for cables that pass through insulation, especially nowadays with the amount of insulation that is in newer builds.
To question and maybe add to point 9, is NOT stripping the cables back far enough so that when they're screwed into a plug or RCBO etc, the screw is not making proper contact with the copper, and is more on the insulation/sleeving? Seen this on another channel but wasn't totally sure why, I'd guess potential arcing?
Arcing is one possibility. More typical is that at that back of a socket, a ring circuit is broken somewhere by one of the live, neutral or earth conductors not forming a ring. Everything appears correct - plug something in and it works, even a basic socket tester - but the cable resistance to any point in the ring is increased because there is only a single current path instead of two. That can result in overheating of cables in a heavily loaded circuit.
The problem here is one of increased contact resistance.
Many decades ago an entire factory burned down and it was because a single screw in a terminal had been tightened up and was partly on the copper conductor and partly on the insulation.
Is the ‘overloading of extension leads’ a thing as the overall daisy chain cannot exceed 13A as the fuse in the first plug top in the chain wins. Discuss ;-) . Assume for sake of argument it is all done neatly and no coiled up extension leads say
As long as the fuse in each plug is correctly rated for the cable, then there isn't a problem.
So you could have a 10 amp lead with a 10 amp fixed plug connected to a 5 amp lead with a 5 amp piug and then back up to a 10 amp lead with 10 amp plug.
The maximum current the chained extension leads can handle is set by the rating of the lowest cable. In this case it is 5 amps.
You might possibly run into a problem with using very many daisy chained cables because of the voltage drop along the cable and that could potentially lead to misoperation of the appliance connected at the load end.
You should see the work of many Australian electricians. My house roof cavity is covered with crisscrossed power cables for lights and power points. None of the cables are marked, there were bare wires at junctions, breakers in the distribution board are not labelled. All done by qualified electricians and all certified by a building inspector when I purchased the house.
Thanks for some great tips. Thankfully, I was already aware of them although the coiled cable was a quite scary. When removing ceilings on my old house I found "rewired" lighting meant, in some places, a few twisted wires with a bit of insulating tape wrapped round them... 😲
I did not know about uncoiling extension leads. Thanks so much for this.
It’s not due to induction, though.
Hi Jordan, old school of wiring a 13amp plug (or any plug infact) is that It should be able to survive a cable pull test. i.e on pulling the cable (with a failed restraint) the live cable should be the the first to be pulled from its terminal. followed by the neutral and finally the protective earth lead. Hence the differential lengths of the terminal wires. There should be enough room in the plug top to accomadate the extra length of the protective earth wire. 😀
One thing common in bodge jobs especially around surveillance cameras is using Ethernet cables for power by directly wiring a few cores of the Ethernet cable to either a DC power supply or even mains voltage. The proper way to supply power using an Ethernet cable is to use a PoE injector / switch with a PoE capable device.
And that works because PoE typically uses 48 Volts, and so the current flow (which is what drives heat dissipation) is only a quarter of that used with a 12 volt device for the same wattage.
Im in the us and wire nuts have never sat right with me. Never liked them. I recently discovered the snap connectors and absolutely love them. I use them everywhere.
The coiled up flex also applies to vaccum cleaners.
Applies to hair drier cables that haven't been unwound too.
Applies to electric kettles whose cables haven't been unwound too.
I see a pattern....
The "connect all the reds" things is why for a long time now I arrange wiring so that there is only one unambiguous cable at each outlet. All junctioning is done separetely from the outlets in junctions boxes specifically for the purpose.
What is the danger in using solder to join two twisted wires together?
I bought a property that had garage strip lights, a switch by the garage doors, and another by the inner house door as change-over switching. Wired with T&E, but one way was bright light, and the other way dim light. Yes it should have been 4 core, but they wired the return through the back box instead- so we got a dim light AND a warm wall.! Surprised it worked actually.
Stranded wires need to have end ferrules properly crimped on before putting them into cheapo screw terminal connectors.
Can you make a video of how you should wire a Uk 3 pin household plug properly.
Thanks for taking the time to make a very balanced and non-condescending video like this. You will never stop DIYers so why not give some helpful pointers. I know over the years I have been guilty of some of them for sure. As the saying goes though. "Only a fool learns from his own mistakes."
Very interesting...... especially the coiled extension reel, I had no idea that was dangerous.
I had aircon installed in my holiday lodge a couple of years ago. Shortly afterwards we were watching TV when we smelled burning. The aircon unit wasn't hard wired, just plugged into a wall socket. The plug had totally burned through, it had a hole in it. Lucky we were in when it happened.
Got the installers out to check things and they said there was no fault, only thing they said was maybe a wire in the plug hadn't been tightened up fully.