The fact that if the relay coil fails it would automatically switch over to the generator, but not automatically switch back again, that tells me that it's a failsafe design. It will at least switch over automatically to the generator, but it won't automatically switch back, giving the operators the ability to at least make sure that mains energy is restored before manually switching back over to mains and cutting the generators off.
Thank you for a well presented and complete explanation of the system. I bought a switch from China but it came without installation instructions. Fortunately I found your site and the excellent explanation. Thanks again from South Africa where we have continuous power outages due to the unfortunate government policy of self enrichment rather than equipment maintenance. Yesterday (Sunday) we had 10 hours of no electricity during a 12 hour period and this has motivated me to connect the generator to the house. Power outages are a daily experience here. Thanks again
Clive - thanks for this. I recently installed one of these for my motorhome to switch between mains and inverter. I was able to get a 4-pole version for the princely sum of £22. Your opinion on this equipment was invaluable. You made what could be quite a dry discussion both entertaining and informative. Great stuff!
@@royblackburn1163 In theory, yes. However it's not something I would do lightly as I'm no electrical engineer. It's never likely to be very useful. I have 150Ah at 12v which makes 1.8kWh at 100% efficiency. Real life is probably less than 1.5kWh. It woul have to be a fairly dire emergency 😁
@@thecommonmeerkat9312 Very debatable we recently had a 9hr power cut lol, I agree they are very rare but if you already have the power it's frustrating not to be able to use it running extension cable's all over the place is messy.
Hey, how has it been holding up? I'm also thinking about getting one of these to isolate grid power from my generator for a few circuits in the house, so I don't need to run extension cords everywhere in the event of an outage. I can't really find any (either automatic or manual) transfer switches, aside from this Aliexpress one. I'm just a little hesitant because, as much as I love junk from Ali, I don't know how I feel about it being connected to mains power with occasional high currents flowing through it. Just trying to figure out if it's safe. Do you like yours? How did you install it (still trying to figure out how to do that neatly as it doesn't really seem to fit in a typical breaker panel).
@@warpedbish-z3z Hi, it's been mostly fine. It worked flawlessly for a while, then stopped auto-switching to battery when mains supply stops. Auto-switching to mains still works fine. Happily, I can still manually switch, so it's a minor inconvenience. At this point, I think that the switching motor has failed. I have bought another unit to replace it. All of these units seem to be very similar.
Am I the only one who just enjoys bigclives approach to everything could watch him cook, take apart, explain, make explosions , drink stupid stuff. Just enjoy the laid back atmosphere technically sound videos. The only thing bigclive misses is a playlist but that’s just nt picking
His voice is just so reassuring. He could tell me the world was about to end, but as long as he had a cheap, generic, Chinese led light in his hands and was ripping it apart, I don't think I'd care lol
I never thought about the back-feeding on personal generators. As a note, I remember Reddit getting angry (so surprising!) about Florida not allowing personal solar installations running after the recent hurricane. I'm pretty sure that back-feeding is the reason behind that choice, and not many people were thinking about that on reddit. Very interesting and definitely something I'll remember!
It would be pointless to "allow" the solar to run anyway, because the systems would be overloaded trying to power the whole neighbourhood. The Tesla Powerwall (and probably its competitors) are smart enough to disconnect from the grid in these situations (legal requirement anyway) yet it can still use the solar to charge itself and power the connected house, so there are still ways you can use your own solar even when the grid is down without running into regulatory problems, it's just a bit more expensive than the cheap grid-tied inverters that come with most installations.
@Undefined Lastname That rarely actually works in real life unfortunately. How do you know who is doing it right or not? send in inspectors of course. inspectors that are kind of way too busy handling the infrastructure right at the moment.
@@vink6163 Ten year minimum return on solar, and then it is outdated or needs new batteries. I will stick with back up propane. If you live in a city you are charged with monthly sewer and water bill. Moved to county, no sewer or water bill,, that savings alone pays for all my energy cost. No ten years loss.
@@robertmccully2792 Only the earliest systems back in the 90s needed 10 years to get a return, nowadays it's much quicker, that's why people are replacing their systems - not because they are broken but because they want a bigger system to save more money. Every second house where I live has solar, and I can tell you people aren't doing it to save the environment, they're doing it to save their wallet. Propane is fine but it suffers the same problem as any other fuel. After an event like a hurricane, your supply can be easily cut off and then once you use up what you have on site that's it. The benefit that solar and wind have is that once they're running you aren't relying on anyone else to keep your lights on.
I only recently came across this video from 2017. About 20 years ago, a friend of mine who is an actual electrician, helped me (who is NOT an electrician) design a generator-based backup power system for our residence. Our residence is in a rural location and subject to frequent power interruptions during summer thunderstorms. These are typically brief (between 1 second and 1 hour). These are not really a huge concern. We use battery-bssed UPS on our computer equipment and flashlights ('torches' on your side of the pond, I believe). In winter, power interruptions are less frequent, but when these outages do happen, they can go on for days. This is because these outages are often caused by ice storms. These can do massive damage to a utility's distribution lines. Repairing these lines is much larger task than is typical with a summertime outage. When power goes out in the winter, you typically also lose your ability to heat your residence. This quickly makes your residence unlivable within just a few hours. We had been chased out of our residence several times by this. We had limited funds but wanted a way that we could ride out these situations in our own home. We knew we could not afford a backup power system that let us pretend there was no outage. We could have afforded a generator capable of supplying much more power but then we would not have been able to afford the other changes we wanted to make. We eventually settled on a 5kv Honda generator - gasoline driven. It was less than what we wanted, capacity-wise. But it allowed us to add a totally manual xfer switch, a recepticle on the back of our house,a second hand-pumped well, and a wood fireplace in our basement. These fireplace can heat our entire residence even on the coldest days. About 12 years after we completed work, we had a 13-day outage. Most of our neighbors were forced from their home. We stayed in ours the entire time. It was primitive but not terribly uncomfortable
Wow! That is a really high voltage for a gas generator. I assume you had to put in a transformer to step the voltage down from 5kv to 120/240V to power your house.
Lol.. honda makes the 5kw ultra quiet model. If they made a 5kv generator available to the public then youd have a lot more fires and dead people.. shit imagine pushing 5kv back through the main pole transformers.. my guess is it would hum for a second before it started doing those "womp" surge flash overs.. if you had a cap inline then a huge ball of fire would be included...
Clive, I like your warning that if it wasn't approved by your jurisdictions and something went wrong you on the liability. There is a lot of things coming in from China to the US that's awfully smart if one only installs certified or listed products.
A very interesting and well presented explanation.....thanks. I have installed a manual change over system with manual interlock and have written a set of procedures to switch off load as I don't believe the Chinese breakers I bought can be relied upon to make or break load. So I change over off load. I found your explanation of back feeding the 11kv brought back loads of memories as an Operation Engineer on the Southern Board' hv networks up to 132kv Now I am talking of the 1960s/ 70s !! The standard was to test and Earth the lines at all hv levels of work before issuing a Permit To Work As indeed there had been fatalities. I recall testing at an old 33 kg sub station to find the back feed was from a neighbouring Lviv network back up through the 11 kg and finally back up to 33 kv. However later I experienced amazingly scary hv practices in Canada and the USA ...but that's another story.
A widowmaker lead, priceless comment Clive . We call that a suicide lead in New Zealand. The risk of backfeed does exist. but Testing and Earthing is mandatory as well as using PPE. Normally a private generator
When we had a generator (US here), we had a cord hardwired into the breaker box that would plug into the generator. In the breaker box, there was a sliding metal plate that would block the breaker for the generator if the mains power was on, and vice versa if the generator was on, so that they can't both be on at the same time.
Not quite what you are showing here, but it brings me back to my apprenticeship and having to manually synchronize three-phase generators with the main incoming 415 volts supply. We, as in a VERY large factory and very large generators, would sometimes back feed AC back into the grid as a load test of our standby generators, this was all done with the electricity supplier's agreement and I think the company got paid for the electricity it supplied back into the grid. While we were being educated on how the principle worked by sinking a small three-phase generator to the main AC supply, I remember one prat of an apprentice deliberately switching over when the generator/mains were not synced and boy was there a loud bang and the generator/mains fuses were blown, I don't remember what happened to the generator, but nothing good that's for sure. With the very large generators, I can't remember how it was done now, it was 45 years ago, but the system we were being shown and educated with was using was very crude, but worked. There were three incandescent lamps, and all three lamps had to be of equal brightness before you threw the switch to sync the little generator to the mains. I'm sure the very large generators were not synced by using incandescent light bulbs, but for the life of me, I can't remember how that was actually done now, old age catching up. Regards, K Watt and yes that is my name and yes I was an electrical engineer
The device you're thinking of (to indicate whether 2 separate supplies are in-phase) is called a synchroscope. It deflects to the left or right if they are not in agreement, and points vertical if they are. www.linquip.com/blog/wp-content/uploads/2021/07/v394xk0cjp821.jpg
I really enjoy your stuff Big Clive! Your explanations are always clear and unambiguous, and you manage to inject just the right amount of gentle humour into every post. I salute you!
My friend in USA bought a more expensive version of this and he has a pretty good diesel generator, and it does it's job and switches with quite a bang! It's well made and works great. Power went out...BANG....generator started up and the lights and everything else came back on. :) Power came back on another loud BANG from the changeover switch and generator shut off, the sound is because of the GIANT contact points in this thing it's no joke.
Interesting Video. In the USA it is law with most utility companies that a mechanical interlock has to be installed on a panel which is connected to a generator. The generator is generally connected to a 40 AMP or more breaker that is in one of the top positions. When mains is turned on the interlock prevents that physical breaker switch being turned on unless the mains power is turned to the off position on the panel.
The issue is these interlocks aren’t great because there are ways you can turn both circuits on as quite often you can remove the interlock or you can open the panel cover. The risk is a homeowner could try and fix something by taking the cover off and see that a breaker is off and turn that on when it is the main one and it’s being fed from generator. with a proper transfer switch it is a lot safer because the average homeowner would not understand how to dodgily bypass it
Great warning. never thought of the danger from back feeding. This video should be shown to anyone who uses a generator for their home that was not installed by an electrician. Thank you. I know at least 3 people I will pass this on to.
The chances all you have never thought about the danger because you haven’t done it because the minute you’re holding a plug that’s going to become live with the metal pins you’ll probably think about
After watching this video I bought one of these and I must say it has worked extremely well. It is for my camper and switches between the solar system (inverter) and shore power. I forgot what the green terminals were for so I returned her to find out. Super glad I did. It is 3 years now and still works great. Not bad for $14. Now I see that the green terminals are just for indicator lamps. Perfect. That will go on my control panel which is remote to the switch.
Nifty device! Bought a rather more sophisticated (and more expensive!) one from the UK, but it's still in its box. Far easier to switch off the incoming power, and PADLOCK the distribution Board! The keys to the padlock are on the same ring as those for the Gennie - so anyone HAS to stop the Gennie (key-start diesel) to get the keys for the padlock - pretty much a fail-safe arrangement.
They HAVE to stop the genny to get the key??... I don't think so. Some enterprising young spark could take the distro box key off the keyring with the genny still running :)
EscapeMCP - there's only the two of us, and The Mrs does NOT like fiddling with the generator!. The generator design is such that key removal can only be done in the shutdown position (basic safety interlock), and I've taken the "precaution" to run a few layers of heat-shrink over the key-ring - so surreptitious "removal" of the distribution board padlock key is challenging. There's also the added barrier of an NVR disconnect between the generator output connectors and the mains connect (our system is effectively a permanent install - no "loose cables with plugs at each end" for us, mate! :-D )
When I was growing up my dad backfed the house. He had a padlock on the breaker panel and during generator operation he kept the key on his person at all times. Not completely foolproof but pretty idiot proof.
D3FTIGE KOST sure it would be, but back in the day having a set up like this was very pricey and most folks couldn’t afford to do things just because they were nice to have.
Do R/C! If there is one thing I have learned over the years it is absolutely, positively, to never underestimate idiots. They will make a fool of one every time if given the chance and are a reliable source of endless surprises.
D3FTIGE KOST ...and additionally, if I recall - houses used to have fuse boxes... ...where to disconnect the mains required physically pulling out something. Not sure what tech would've existed at that time for this; there may have been something.
For our American panels, you can get what is called a generator interlock kit, where you have the breaker from the generator input (and also a proper twist-lock male power connector on the side of the house that actually plugs into the generator), as well as a piece of metal that will go on the main breaker and the generator breaker, and prevent both from being on at the same time, so you can't backfeed and can't get a shock from the exposed metal on the male power connector.
This is incredibly unsafe because the cover could simply be removed where there is something unintentionally happening which then causes both supplies to be energised such as if you only have a fault and open the panel to meet some things there was a chance both supplies could be turned on
As far as preferred source, like you mentioned in the entertainment industry. Most decent, new transfer switches allow for settings that monitor the primary source (utility) quality. If it has transferred to emergency/generator after a utility outage, it will monitor the utility (for over/under voltage and frequency, as well as phase imbalance) once power is available again. Then once the power quality settings are satisfied, a transfer delay timer starts. If utility falls outside of those voltage, frequency, or balance parameters within the delay timer (say 15 or 30 minutes), it will reset the timer, monitor for correct quality again, then repeat the cycle.
We don't have many power failures to worry about, but boats is need to switch from shore supply to generator and even a battery with inverter. Usually we get no more than 10amps coming in. The usual approach was to have three switches with a sliding panel that prevented more than one being used at any time. We would start the generator and warm it up before switching off the shore supply and switching on the generator. In the same control panel we had switches for all the loads. It was common practice to flip them all off before the switch over to generator, and then switch each back on in sequence, allowing each to settle before adding the next load. It sounds complex, but if you understood what was happening it soon became second nature. We would have to think whether we really needed the water heater or air conditioner or battery chargers. I love automation but sometimes it's sensible to make your own decisions.
Hi Clive, yeah we across the pond call it a 'suicide cord'. I do this Clive, BUT before I even go to the shed where the gen is, I go to the pole and beneath the meter is a double breaker. I shut it off and put a lock on the box. I also shut off MAINS in panel in house. This way there is NO way to backfeed to the grid. ALSO some utility companies might decide to to NOT give service to that house if they find a gen improperly hooked up, backfeeding into the grid.
This Tomzn transfer switch looks economical. I know installing a turn key auto transfer switch to your house is quite expensive and involve adding several more control boxes outside. In case you want to know , for Canada, the high voltages outside on the pole starts at 4160V, then double that to what we call 8000v and double again to 13 -8V etc. The dryer is not the biggest power outlet in most homes at 30 amps , most homes have stove outlet rated at 50 amps that we put on 40 amp breakers. But some who have gas ranges had the outlet removed or converted to a regular 120 V outlet. A gas stove still need 120V. In UK, when power is available (had to put that line in) it is 220 v with one line to ground, or neutral. In Canada , you need 2 live lines together to get 208 or 240 V The neutral is necessary if you want 120V from either voltages. Many motors or heaters will just work without the neutral. being a electrician for decades, it is against my religion to shell out big bucks for a transfer switch. I can use a "suicide" cord, or I just back feed the breaker, but I highly doubt I get zapped. Linesmen working on outside lines either assumed the line is live or they been grounding it for decades. It is extremely rare to see one of them hurt on the job.
I'd be worried about that relay being mounted hard against the PCB. Depends on the construction of the relay, but that's almost certainly a bad idea. With the relay mounted hard against the board, even if it's a single-sided board, as the joint cools the relay pins will contract slightly as they cool. This puts strain on those leads which, in that style of relay, means it can cause slight contact misalignment and/or loosening of the entire structure. It also means (going by how you drew it) that pads on the relay base are in contact with the PCB leading to moisture traps (which encourage corrosion and fungal growth). Don't mount components hard against a PCB if you want the design to be reliable. As an aside, wicking of the solder up the through-plated hole is not only normal, it's *desirable* in high-vibration environments because it stops both pushes and pulls on the component leads peeling the track away from the substrate. In aerospace applications you may find PCBs with all the tracking on one side but still using double-sided board with TPHs just for vibration resistance. BTW, I find a good solder sucker is better than braid for removing components on double-sided or multi-layer PCBs. It sucks the solder through the hole, removing it from both sides of the PCB.
I've trained as a Canadian Electrician so I'm not familiar with the USA's NEC. In Canada, ALL Residential Generators MUST be connected to the Circuit Panel (Breaker Box) with an Interlocked switch that physically disconnects the City feed when the Generator feed is active. This prevents the Generator from back-feeding into the City Grid and thus keeps it from Electrocuting any Hydro Linesmen (the Electricians Licensed and Trained to work on the multi Kilowatt Power Lines). I believe the NEC has a similar Regulation.
Happy to see that I‘m not the only old man still having the 12y old „let’s ripp it apart“ mentally. At least from time to time. But at least for cars I‘m saved by a company car. 😎
I've got one of these auto transfer switches. I modified it slightly, so the green terminals on the bottom are to enable switching in either direction rather than output signals. I mounted a relay board right off the terminals and from there goes to an arduino outside of that box. this way, I can have the arduino decide when to transfer power to or from the generator with a delay. transfer doesn't happen until power is stable from utility or from the generator.
The delay isn't a bad thing, you can have a UPS to run your computer or radio transmitter. The device in the video has me thinking of other application, such as off grid events such as Amateur Radio contesting.
one thing I learned, if you're using an inverter or inverter generator or anything that provides a clean and stable 50/60hz power, a normal ups should hopefully work ok. but, they can be picky. my backup generator isn't the inverter type, so the AC frequency changes with the engine rpm. a normal ups will switch to battery thinking power is unstable. there's a thing called a double conversion ups. they use a bit more power, slightly less efficient, but they will take whatever power you give it, clean it up nice and pretty, and offer that to your valuable equipment. I got a few made by eaton, I found it'll keep using utility power down to about 60 volts and wont use the battery. because it's only getting half the voltage but still needs the same amount of watts/power for the equipment, it actually draws double the current at 60 volts. if I drop it to 55 volts, it finally switches over to battery. that's pretty neat. it takes the AC power from the wall, utility or your own generator or any source, it converts it to DC, then back to a clean stable AC. a normal ups only needs to convert DC to AC when it's running from battery, but a double conversion ups is always doing this the entire time it's on. back to the thing about delay being a good thing, yup. when the generator starts, I don't want an immediate load put on it. likely it could stall out. at least give it a few seconds to come to an idle. that's why I modified my transfer switch to have inhibit relays controlled by arduino. I can monitor power sources and have a set delay. planned project, maybe will finish soon.
@@UKsystems nope, can be more safe. depends how it is designed. in my case the relays inhibit the transfer by default. the auto transfer is not possible unless the transfer switch itself is ready to allow it, and the relay is activated to allow it. multiple fail-safes. 1. utility power needs to be cut 2. the backup power source needs to be ready to provide power 3. the manual/auto switch needs to be set to auto 4. the inhibit relay needs to be active. if all these conditions are not met, nothing will happen.
I used to manage the IT operations of a small company that hosted everything onsite for compliance reasons. Our automatic generator cutover switch was poorly installed and almost never worked, probably the worst event coming when it couldn't make up its mind if the mains power was back up or not, leading to a situation where it just flapped between mains and generator until I manually killed the generator. Finally, after three visits from our "qualified" electricians, culminating in a full day-long shutdown of the facility the issue was resolved. These were the same electricians who wired 220 to an unmarked NEMA5 outlet, leading to my AC guys plugging a 110v appliance in to it and throwing a breaker.
Wow, in the US and have had a generator for years and not once have I thought of back feeding the entire house through the 220v dryer connection. Scary. And no, not gonna try it, no way. I'll let you do that one so we don't have to...
I have seen a video with a pto generator feeding at the utility pole, guy switched off the power line, then had a three phase plug at the pole to power barns and the farm houses. Better that then feeding it through a dryer plug.
I was just asked to do a video on the transfer switch for one of my recent backup power testing videos. I couldn't have done a better job than bigclive! Big thumbs up!
Clive, I work in the Genset Industry, we would not allow that type as ATS without feedback validation to validate That the switches are in the correct mechanical positions.
That's one thing I want to buy. Not because I could use it but because the mechanism is awesome. The problem is 28 bucks are not in the price range of "Ill buy it just because" things.
A great sports commentator is able to describe the action so well you can watch it on your radio, well you are that good, I watched the whole thing being away from the screen, by just listening to your great commentary! I’m sure the video is just as good! Awesome
I installed my own wiring and generator inlet and ran it to the electric panel with an interlock kit, you just have a metal plate that physically blocks you from powering the panel with the generator until you switch off the main. Simple and cheap like $45 or so and practically accident proof from back feeding. The down side is that the generator will not power on by itself when the power is out but for me it is a rare event to lose power, a bad snow storm in 2018 and 2019 left us without power for 1-2 weeks and always ready in case of an earthquake.
US is different to UK and most of Europe where DIN rail mains panel is common. Not seen any metal plate interlocks for them here. It always amazes me how much power distribution is overhead in the US, making it vulnerable to the weather. Japan is similar and some Asian countries are mind boggling with their rats nests of cables! The UK has a lot of overhead wiring too, but nowhere near as much as US. Germany has almost all theirs buried underground, even in most villages. Power outages are extremely rare.
In the US backfeeding into your home without disconnecting it from the mains will result in huge fines and possibly jail time depending on if you get caught. Though getting caught will be pretty easy with the new smart meters that consumers has installed. They monitor for blackouts and record if and how much power is backfed into the system from your house in real time via two way link. There is some leniency in the system for a noisy computer or sump pump backup or things of that nature where you might get a couple watts of energy, bot something large and they are going to send a hefty fine your way. We are in a trial area for the smart meters, they also have the added feature of daily usage reports through the online portal.
It would seem logical to put a generator transfer switch in series between the main breaker and the rest of the panel. That way if it trips, it effectively disconnects the mains automatically. I am pretty sure this is what those big commercial generator systems like the big natural gas Generac systems do.
Not really, simply switching off the main switch after the meter will stop it from surveying anything. In the case where the house is backfed from an internal circuit, the meter will not see anything.
I've designed, wired and tested dozens of changeover systems, typically 2000A 400V or 10kV, with up to 6 timing relays, voltage monitors, trip contact supervision, 20 aux relays. This one is clearly done as simple and cheap as possible. Fun to see.
zx8401ztv Save for their rather paltry 3KA interrupt rating. I know Clive mentioned a minimal interrupt rating of around 6KA for his country and here in the U.S. typical residential interrupt ratings are around 10KA for branch circuits and greater than 20KA for the main breaker. Which is to say, if they actually had to handle a dead short condition there is a real risk of the entire unit simply exploding into bits with possible injury and fire. As such they would need upstream protection to protect from severe short circuit conditions. To me these seem more suited to dual utility feed connections where one has two incoming power feeds from the utility (such as from differing substations) as this automatic transfer switch does not actually provide for starting the generator nor does it delay transfer to, and away from, the generator to allow the generator time to start, stabilize, then assume the load as is typical of automatic transfer switches intended for generator applications. For this switch to really work with a generator "automatically" the generator would have to be on continuous standby and running 24/7, which is ordinarily only ever done in very critical applications (and even then it is common to allow battery or flywheel UPS power sources to support critical loads while the generator starts and power transfers over to it at which point the UPS returns to standby duty in case of a generator fault, at which point the backup generator is started and the process repeated, or to support loads while switching back to mains when utility power is restored).
It wouldn't even pass CE approval. The leds themselves poking trough on the front are litterally the only insulation between you and the mains... aside from the soldered connections on the breakers... This device is a nice idea and proof of concept, but that's about it. Not safe.
Good advice to add extra 63 Amp MCB's in series with the transfer switch unmarked MCB's. It worries me that the manufacturer doesn't label those MCB's, they could easily be cheap unbranded knockoffs. We are talking mains supplies here so the equipment has to be safe. I prefer always a dead or zero position when changing over a transfer switch. (generator - zero - mains). With that double 3 kA rated MCB at the end, under fault conditions and arc flash could easily happen with serious burns to the unexpected home owner, who is usually not an electrician.
I wired a farm building once using a 240-drop (out of the circuit box) and a 50-amp breaker. To resort to your 2nd input, you had to turn off the main, then turn on the 50-amp breaker (which acted as a 2nd main for the generator)...no harm, no foul, and gets around having to buy a $150 transfer switch....that said, it is NOT TO CODE in the U.S. (don't let an inspector or electrician see this barn-burner circuit!) A far-easier way to do this is to simply drop a circuit to a small box and use a 3-position rotary switch rated for the circuit to act as a transfer...which in circuit, would replace the breaker in my example. Again, MUCH TO BE SAID FOR RELAY-DRIVEN TRANSFERS where you have a 'dead pole' at midpoint, so that you cannot have BOTH SUPPLIES HOT at the same time (bad, BAD news for the power company, your home, etc....because they are not in sine polarity with each other!
The only thing I don't like about this unit is the "break before make" is very slow, it would be nice if it switched over quick enough for the devices connected to it would not lose power. However you could solve this problem by using a UPS (battery backup) in between the ATS and the connected devices.
If you’re looking at professional solutions, they’re going to come with a professional price tag. There are a lot of models now in a rail format that are on the 50 ms.
I assume for myself that transfer switches (be they manual or automatic) should at any means avoid accidental connections between power sources. So it is impossible simultainlessly cut off one input and get feed from opposite. There must be two-step sequence: break connection to the current input, only then make connection to alternate input, with some delay in between. Hager 1-0-2 switches works exactly that way. Meanwhile, many popular chinese ATS produce just one loud click w/o noticable delay (8ms by specs) and they known as arc-prone with fried contacts in the end. From this point of view that motorised "slow" model in this video appear to have rather right habit, first it momentarely turns down one break pair and only after that slowly turns up another break pair. (Sorry for my poor English)
touching the leads while both the plugs are unplugged.... You're a daredevil! even though I'm quite confident in my knowledge of "low" voltage circuits and electronics in general... I'm always assuming that I'm delirious and that I might have forgotten to unplug it.
Great video. Something that would be interesting to take a look at would be those 3000w 230v solar power inverters. Can they really deliver 3000w without noise etc?
I am looking for something alike, to install in my flat to power 3kW storage heater using night tarrif as main, and normal (day) power as backup. In my mind backup will always be on, but "night/main" power will be switched. Great videos Clive, like watching and picking up knowledge.
I was thinking about how that transfer switch could have a breaker instead of just being a switch myself because the motor wouldn't necessarily allow it to turn off. It dawned on me at the end of the video that, in the event of an overcurrent, the breaker would move to the trip position and not the full off position, which of course, theoretucally, wouldn't affect the position of the motor arms at all.
Great video. I just might buy one to play around with. I do wish you had dismantled one of the switches to see if a) these are circuit breakers or just switches and b) the contacts are even close to adequate for the current rating. The Chinese are notorious for claiming a 20A switch contact can handle 40 or 60 A. Of course, they soon burn up.
You must have come across JIS screwdrivers, Clive? Japan Industrial Standard. Much better fit for far eastern screws also work well on Philips screws. No climb out. You can get Vessel brand JIS drivers of all sizes on Spamazon. Not cheap, but a real investment.
bigclivedotcom , Had to pause at ~ 5 : 00 and compose a comment here - from across the pond - to say that you are another one of those high value propositions, high ROI of my time watching your videos - right up there with Techmoan, the Essential Craftsman and so many others I'd have to take more time to recollect; yet, and still there's not seemingly enough of the like and wanted to tell you your content and its presentation is top notch as I don't give a hoot about production value near as much as the message content and spirit, diligence on practice of topical scope and relevant theory infill , perspective and therein a richness and whether or not I came away a better mind for the experience. Can't say enough without droning on - thank you! I appreciate your preparation and explanation / teaching methods!
I wish that you had pulled the breakers apart to see whether or not they were indeed MCB's or not. I shouted at my screen, but I don't think you heard me. :(
I doubt they are MCB's. Every ATS I've installed (100's) doesn't use breakers, just isolaters. Protection is done from the main board and from the gen source.
So relevant now!!! There are a bunch of these on ebay. All look like 63A! A lot of folks are gonna be running their generators this winter when the blackouts and Brownouts kick in. Welcome to 2020+2!!
You raise the issue of backfeeding the incoming supply from a generator during a powercut. Of course, sometimes this is desired - eg solar panels or other local generation - so are there systems which will prevent these from feeding in when the mains power fails? But of course it would be neat to continue to be able to access any power they are generating despite the mains supply having been dropped.
Inverter chargers can do this, they act as a mains grid that will take excess power and charge batteries which also completely isolates the 14kv residential lines eliminating a potential death shock. Most, if not all solar inverters have island protection which means that if the sine wave of the grid disappears the inverters do a safety shutdown.
The problem with anti-island protection systems is that if you DO have a mains outage, your Grid-Tie inverter stops dead. So, even if you've got solar capacity, you can't use it. There are ways around this - our strategy is to isolate from the Mains and use a standard (no Grid-tie) inverter to provide power. Once again you MUST ensure isolation from incoming Mains, and therefore you MUST have some form of fail-safe disconnection system or protocol (for equipment and safety reasons!)
our solar roof setup (7.5kW peak) turns off if no 50Hz Sine, or difference to 50Hz is more than... 0.02 Hz i think it was ?? Only Necessary power needed here would be for central heating (+ cooking). Warm water is mainly gas, secondary electric heaters. I cant remember having a power failure at home in years, even then it always was over before you knew what happened, AND the one failure i got at work (street working company dug into main line) was fixed within 20min before the "manual generators" were connected properly... (Thanks to isolated subnets with multiple feeding points) BigBoss was making everybody stressed for no reason (phone lines only work a certain amount "off time" via local backup in distributor anyway) And when (very small) Gen was hooked up to main server running (unloved old usv starting to run low..), he plugged in shitload of unnecessary things (phone, PCs...), so the generator shutdown with overload. If we just went for a walk 20 minutes, all would have been fine after that. But then all Server and Phone and "Stuff" had to be replugged where it was originally, and it took over an hour until normal state. ...You wont find a single power line sparking for more than one " lightning arc" here if ripped off, without anyone needed to shut it down.
our solar roof setup (7.5kW peak) turns off if no 50Hz Sine, or difference to 50Hz is more than... 0.02 Hz i think it was ?? Only Necessary power needed here would be for central heating (+ cooking). Warm water is mainly gas, secondary electric heaters. I cant remember having a power failure at home in years, even then it always was over before you knew what happened, AND the one failure i got at work (street working company dug into main line) was fixed within 20min before the "manual generators" were connected properly... (Thanks to isolated subnets with multiple feeding points) BigBoss was making everybody stressed for no reason (phone lines only work a certain amount "off time" via local backup in distributor anyway) And when (very small) Gen was hooked up to main server running (unloved old usv starting to run low..), he plugged in shitload of unnecessary things (phone, PCs...), so the generator shutdown with overload. If we just went for a walk 20 minutes, all would have been fine after that. But then all Server and Phone and "Stuff" had to be replugged where it was originally, and it took over an hour until normal state. ...You wont find a single power line sparking for more than one " lightning arc" here if ripped off, without anyone needed to shut it down.
I’ve done something similar with a solar water heater changeover switch using two motorised valves, to switch between a combi boiler and a solar heated water tank dependent on water temp. My relays are off in the default state which is predominantly solar tank is hot and I can turn off all power to save the relay coils. I also have a manual override for winter. I think the design of the power transfer switch could be improved by only energising the relays when the generator comes on, and use a normally closed relay using no power when on grid power. Love your tutorials btw you’ve been an inspiration albeit mostly above my level of knowledge.
Great idea! I'm just about to do the same thing: a motorized valve that can select either my solar hot water or a new propane tankless water heater. The valve will be controlled by the mechanical thermostat on the solar hot water storage tank. I'm confident it will work just fine. And as you point out, I can control the valve manually to save the relay coils.
a neat trick for hot melt glue that's in hard to reach places you can't apply much force or heat is to give it a shot of freeze spray makes it hard as a rock and allows it to crack off the surface of things easier
It wasn't supposed to be released yet as I hadn't actually added the text yet. I uploaded it as private and it appeared as public. It will be released in a couple of days.
We just lost power in my house, and we had to manually run an extension cord from our generator to a power strip in the kitchen which we plugged the refrigerator to, and then we ran an extension cord from there to the freezer across the room, and we had to move the microwave to plug that in, and had to get a standing lamp for light, and everyone had to be in the room to charge their laptops and phones, and it was aweful, so sad. We need to get one of these, but unfortunately I don't think our insurance will like it if we got it from eBay.
XDSDDLord You can plug the generator directly into the house. You need an extension cord with a double male end, turn off the main breaker, turn off breakers to non essential parts of the house, and turn off any non essential devices, then plug one end of the cord into the generator and the other into any standard outlet and it will power the whole house. Be careful to not overload the generator though.
Yeah..exactly thats the way a unwary person does it "extension cords", and now even gets proposed to build and use a widowmaker. Because people need to use life essential things like mobile phones and laptops 😬 to survive.
any transfer switch will have to be inspected and approved by your local electric inspector,otherwise if you do have a fire or whatever your insurance is not obligated to pay.Cheaper in long run to have it done right
XDSDDLord Proper manual transfer switches are not all that expensive and are well suited for manually started generators. There is really no need to go the questionable China post route when you can get a perfectly compliant manual transfer switch for a reasonable amount. I live in upstate SC where ice storms are not at all uncommon (typically one or two every several years) so we have a 15KW generator and a 200A transfer switch installed just in front of our house main breaker panel, allowing is to choose which circuits are generator powered by selecting which circuits are switched on in the panel with a watt meter displaying the load on each of the 120V legs so that each leg remains within the load (6,250W) the 50A circuit breaker from the generator will support without tripping. However, you can buy ready made generator subpanel that are reasonably priced that will support up to a dozen, or so, circuits throughout your home when on generator power and are easy to install once you choose which circuits you consider critical.
Two things I'd love to say, first is that Clive is my hero, and I learnt all my electronics through this channel, especially the Fanny Flambeaux doll vid. Second thing is that I have a 4 pole contractor with mechanical and electrical interlock set up, and I run the outputs into one of these Tomzn mechanical transfer switches, but a 4 pole version. The contractors change over is close enough instant, but with this Tomzn unit inline, the delay is increased and also, if the breakers failed, I'd rather that then a sticky contractor. Love this unit, and I love the simple wiring on the output indicators. I had to watch this then ask when you join the output contacts together would that back feed the indicator for the mains but the relay solves all that gunk.
Good work Clive... Could a guy use a double pole double throw switch ? By connecting the two ( P ) terminals to the INPUT side the the breaker box, and then connecting the two ( T 1 ) terminals to the main feed coming from the pole transformer, and then connecting the two ( T 2 ) terminals to the generator. That way the house can only be feed by either the mains or the generator,,, but not both... I was going to do this to feed my furnace. I have a 3kw inverter, and a very large motor home battery. But , alas, , once I figured out that it could be done,,, why do it... Keep up the good work. ..
Ooh, nice! Does look a bit shoddy round the edges though, like typical Chinese shite manufacturing. Like bits are going to fall off, and the thin plastic case is gonna crack quickly. If you had a well-made version of this switch, I'd want it. Dunno what I'd actually do with it, like. Just use it as a light switch I suppose.
RDJim Not seeing the internal workings it us hard to tell if it would be heavy duty enough. But by the description in the title that is what I had in mind... But to actually do this to the whole house,, upon further thinking, I would use a triple pole double throw switch... I hope this helps... But at any rate,,, I am guessing that for insurance purposes you would need an electrical contractor to sign off on this installation.
Wily Bee, A transfer switch/relay is normally just a big double throw switch or relay. In the switch, there normally is a center off position also. In the relay setup, it can be done with a single large DPDT relay or two single throw DP relays. In three phase setups it almost always is done with two 3 pole single throw relays with a delay circuit on them. The tranfer switch on the side of our house is one that is DPDT Center off but has the ability to have another set of contacts added to use as a 3 phase unit. It is currently fused for 200 amps 240 volts but can take up to 600 amps at 480 volts. When you throw it, it makes a very loud thunk and the lever part is over 18" in length. It is lockable in all positions too.
Liking the fact it uses a motorised manual switch. The ones i've studied in the past use interlocked contactors and i didn't like the fact that I had to rely on a contactor being energised all the time for normal on mains supply - despite working in IT where such devices protect significantly more important stuff than my house! I went for a manual changeover in the end for the sake of simplicity and avoiding spikes and surges swapping between genny and mains.
Eliot Mansfield This one still has an always energized coil. And the mechanical interlock is incomplete if that motor stops halfway through (as briefly spotted but dismissed as "will never happen"), even more likely in manual mode. Anyway, I think all these "two-breakers and lots of mechanics" designs for transfer switches are just stupid with too many things that can fail and overcomplicated user instructions. A properly overbuilt break-before-make changeover switch is a much better starting point for designing these. Automatic changeover would just move the one 4-pole/3-pole/2-pole switch, not try to dance around two switches.
UA-cam released a video uploaded as private before I could complete the associated description and data. It will be released properly in a couple of days.
bigclivedotcom ah ok I gotcha thanks for straightening that out now I'll be able to watch the change over switch video without thinking about the other vid and to what happened thank you for my peace of mind lol
Clive, thank you do much, nice to see the detail in it, nice and neat little design. I really enjoyed the The breakdown of it, And yes the case was a joy to watch come apart with the removal of the keystone screw.👍 Oh and I might add there was a day of power issues a while back that had people coming into the supply place where I worked and asking for a heavy double male plug for their generator. Their anger and hostility that we didn't have one on the shelf was amazing to me, because I would've never done this, I was a bit oblivious to what they were doing Until I worked it out later. But in the interim I stopped explaining any of it to them, and just suggested they talk to an electrician. The guff I took from them was amazing, and pushed me into a posture that if they were too stupid to figure out how to build the cord, and we're angry because we didn't start such a thing, I wouldn't tell them how to do it, and ended my assistance. Sometimes it would come Knowing they shouldn't have such a thing or do such a thing, I will try and avoid telling me what they were doing. They really didn't care about the workmen, and weren't smart enough to shut off the main. Serve like an old boss of mine the thought his friend was such a genius because he where is his garage with the supply from the house as a single wire (single conductor), he thought the guy was genius, when in reality is money saving technique ordered on some insanity level. All it takes is one loose thoughtless day of him Dragon aluminum extension ladder through his yard or or some other site not realizing that electric mouse trap was there waiting for them and Presto, dead guy. Thanks Clive, another great video.
On boats I just use one relay with 2 x NO and 2 X NC. The two NC contacts are used for the inverter power, the NO are used for shore power. In also feed the relay coil from the shore power. This makes the ship run on its own power unless the shore power is connected. Switches fast enough for computers to keep running.
I'm with you on the always-powered relay; not something I like to see in practice, when some logic (µC or other) can accomplish the same thing, using a lot less power.
In the US, if you've got the right kind of breaker panel, you can get a mechanical interlock which mounts over two breakers. One breaker is the main utility and the other is for the generator. It prevents both from being on at the same time and thus prevents backfeeding. Very inexpensive compared to proper transfer switches which are quite expensive. I can't use one, so I just use 12ga extension cords for fridge, microwave, lights and electronics. except for my gas hot air furnace which has a small transfer switch.
I like it just that it does not have that circular plug where you can plug another battery or your ev etc. Also I would love to be able to control which of the items plugged into my solar are off but then again just turn them off at the wall. What do you think
One of my jobs many years ago was pat testing within the company .in one department was a very nicely made bench on wheels so it could be used within the lab.Anyway pat testing must have been lax in the past because when i unplugged the plug connecting it to the mains (it in reality was just a extention lead but with conduit feeding several sockets along the back ) i unplugged it from the supply and plugged it into the pat tester and everything went black!Once the power was restored i noticed the problem the designer had in his wisdom fitted a clone lead on the other end !!!!Ofcourse i was lucky i didnt inspect the first plug or i would have found to my dismay the pins would be live fed from the other plug .Repremands were made and i left with 6ft of wire with a plug on the end and the knowledge to look a bit harder in the rest of the building
Thank you so much for the precise to-point informative orientation. Can you also do the practical video clip of the wiring process from the panel control to the generator auto battery connection for ATS
The break before make design both ways is because AC phase difference will make something explode if the generator ever gets in parallel with the mains. The circulating current will be huge before the generator locks into phase if it is even designed for use in parallel.
A generator accidently tied to the utility power will almost instantaneously trip the overcurrent devices because the amperage will be sky high for milliseconds. It cannot continue to operate. Nothing will explode.
My grandparents backfed (probably still do) their house through the 220v dryer plug here in the US. I was taught once when there was a power outage to disconnect the main breaker to keep the generator from blowing up.
you stated an inaccuracy that in the USA, the 30A dryer outlet is the highest power connecter. we also have NEMA 14-50 (50 amp) and NEMA 14-60 (60 amp) outlets. this NEMA 14-60 is our highest power *2-phase* outlet & plug. but the 30A dryer outlet is *commonly* the highest power outlet in some homes. (but this is only with homes with an electric dryer. gas dryers are very common too, which only use 120V circuits.) But now with more popularity of Electric Vehicles, more and more homes are getting wired for higher power & higher amperage 240V circuits.
Searched UA-cam for your video on this transfer switch. (bought one on Amazon from china, curious to how its engineered) sure enough here it is. Thanks for saving me the trouble of having to send you one for a video 🤣
I'm curious to the draw from the relay. Because I'm using battery/inverter as the main ac input, and my shore cord/gene is going to be wired as the backup. Since the relay coil is always powered if main input has power (by my battery Bank/inverter) I haven't yet installed it, or my smartshunt would tell me the draw and I wouldn't be typing this lol
Two drawbacks of this circuit:1. LEDs could burn out in short time because of reverse voltage of 300 volts. There should be silicon diode in series to prevent that.2. I've been taught that you should never put two different high-voltage sources to the NC and NO relay contacts. There is possibility that arc which arises between moving contact and NC would extend to NO and stay there until something burn out. These relay contacts could be arranged in safer way probably.
AllMyCircuits Given that the Chinese often use/produce custom silicon or make careful device selection where such will lower production costs by eliminating components, it is very possible that the LEDs consist internally of two back to back LEDs that effectively limit the peak reverse breakdown voltage seen across the reverse biased LED junction with each half cycle. If they never see more than ~2V when reverse biased then no breakdown will occur and thus no damage to the LEDs over time. This would also greatly reduce perceived flicker since their flicker frequency would be twice the line frequency. Such are effectively identical in construction to ordinary bicolor LEDs, only in this case both LEDs would be red.
As the new clive's video states, that's not the case: they just use old-type LEDs which tolerate reverse breakdown pretty well (at least when we conduct less-than 1 mA of current this way) so the continue to work for quite long. Doesn't work with modern ones though...
A bigger potential failure point would be mechanical. If the switching mechanism breaks, such as having the plastic switches break, then it could potentially have both mains power and the generator on at once. The covers do protect against foreign objects getting in the way, but it also means you can't visually see how the switch looks.
The fact that if the relay coil fails it would automatically switch over to the generator, but not automatically switch back again, that tells me that it's a failsafe design. It will at least switch over automatically to the generator, but it won't automatically switch back, giving the operators the ability to at least make sure that mains energy is restored before manually switching back over to mains and cutting the generators off.
Thank you for a well presented and complete explanation of the system. I bought a switch from China but it came without installation instructions. Fortunately I found your site and the excellent explanation. Thanks again from South Africa where we have continuous power outages due to the unfortunate government policy of self enrichment rather than equipment maintenance. Yesterday (Sunday) we had 10 hours of no electricity during a 12 hour period and this has motivated me to connect the generator to the house. Power outages are a daily experience here. Thanks again
Clive - thanks for this. I recently installed one of these for my motorhome to switch between mains and inverter. I was able to get a 4-pole version for the princely sum of £22. Your opinion on this equipment was invaluable. You made what could be quite a dry discussion both entertaining and informative. Great stuff!
Can your motorhome power your house ?
@@royblackburn1163 In theory, yes. However it's not something I would do lightly as I'm no electrical engineer. It's never likely to be very useful. I have 150Ah at 12v which makes 1.8kWh at 100% efficiency. Real life is probably less than 1.5kWh. It woul have to be a fairly dire emergency 😁
@@thecommonmeerkat9312 Very debatable we recently had a 9hr power cut lol, I agree they are very rare but if you already have the power it's frustrating not to be able to use it running extension cable's all over the place is messy.
Hey, how has it been holding up? I'm also thinking about getting one of these to isolate grid power from my generator for a few circuits in the house, so I don't need to run extension cords everywhere in the event of an outage. I can't really find any (either automatic or manual) transfer switches, aside from this Aliexpress one.
I'm just a little hesitant because, as much as I love junk from Ali, I don't know how I feel about it being connected to mains power with occasional high currents flowing through it. Just trying to figure out if it's safe.
Do you like yours? How did you install it (still trying to figure out how to do that neatly as it doesn't really seem to fit in a typical breaker panel).
@@warpedbish-z3z Hi, it's been mostly fine. It worked flawlessly for a while, then stopped auto-switching to battery when mains supply stops. Auto-switching to mains still works fine. Happily, I can still manually switch, so it's a minor inconvenience. At this point, I think that the switching motor has failed. I have bought another unit to replace it. All of these units seem to be very similar.
Am I the only one who just enjoys bigclives approach to everything could watch him cook, take apart, explain, make explosions , drink stupid stuff. Just enjoy the laid back atmosphere technically sound videos. The only thing bigclive misses is a playlist but that’s just nt picking
Wats ollin you're not the only one, there's at least me as well. His delivery and knowledge are very appealing. Seems like a nice guy as well
His voice is just so reassuring. He could tell me the world was about to end, but as long as he had a cheap, generic, Chinese led light in his hands and was ripping it apart, I don't think I'd care lol
Doug Reed It seems he's not the only one at all
he has great informative videos, a nice voice and pleasant accent, but I can't stand hearing him eat candy...
ua-cam.com/play/PLhobEwm5JtcF-ATS8fUHmXxulpLFmZs9J.html
I never thought about the back-feeding on personal generators. As a note, I remember Reddit getting angry (so surprising!) about Florida not allowing personal solar installations running after the recent hurricane. I'm pretty sure that back-feeding is the reason behind that choice, and not many people were thinking about that on reddit. Very interesting and definitely something I'll remember!
It would be pointless to "allow" the solar to run anyway, because the systems would be overloaded trying to power the whole neighbourhood. The Tesla Powerwall (and probably its competitors) are smart enough to disconnect from the grid in these situations (legal requirement anyway) yet it can still use the solar to charge itself and power the connected house, so there are still ways you can use your own solar even when the grid is down without running into regulatory problems, it's just a bit more expensive than the cheap grid-tied inverters that come with most installations.
@Undefined Lastname That rarely actually works in real life unfortunately. How do you know who is doing it right or not? send in inspectors of course. inspectors that are kind of way too busy handling the infrastructure right at the moment.
@@vink6163 Ten year minimum return on solar, and then it is outdated or needs new batteries. I will stick with back up propane. If you live in a city you are charged with monthly sewer and water bill. Moved to county, no sewer or water bill,, that savings alone pays for all my energy cost. No ten years loss.
@@robertmccully2792 DIY and contracting yourself can cut it down to 3-5 years with current tax credits.
@@robertmccully2792 Only the earliest systems back in the 90s needed 10 years to get a return, nowadays it's much quicker, that's why people are replacing their systems - not because they are broken but because they want a bigger system to save more money. Every second house where I live has solar, and I can tell you people aren't doing it to save the environment, they're doing it to save their wallet.
Propane is fine but it suffers the same problem as any other fuel. After an event like a hurricane, your supply can be easily cut off and then once you use up what you have on site that's it. The benefit that solar and wind have is that once they're running you aren't relying on anyone else to keep your lights on.
I only recently came across this video from 2017. About 20 years ago, a friend of mine who is an actual electrician, helped me (who is NOT an electrician) design a generator-based backup power system for our residence. Our residence is in a rural location and subject to frequent power interruptions during summer thunderstorms. These are typically brief (between 1 second and 1 hour). These are not really a huge concern. We use battery-bssed UPS on our computer equipment and flashlights ('torches' on your side of the pond, I believe).
In winter, power interruptions are less frequent, but when these outages do happen, they can go on for days. This is because these outages are often caused by ice storms. These can do massive damage to a utility's distribution lines. Repairing these lines is much larger task than is typical with a summertime outage. When power goes out in the winter, you typically also lose your ability to heat your residence. This quickly makes your residence unlivable within just a few hours. We had been chased out of our residence several times by this.
We had limited funds but wanted a way that we could ride out these situations in our own home. We knew we could not afford a backup power system that let us pretend there was no outage. We could have afforded a generator capable of supplying much more power but then we would not have been able to afford the other changes we wanted to make.
We eventually settled on a 5kv Honda generator - gasoline driven. It was less than what we wanted, capacity-wise. But it allowed us to add a totally manual xfer switch, a recepticle on the back of our house,a second hand-pumped well, and a wood fireplace in our basement. These fireplace can heat our entire residence even on the coldest days.
About 12 years after we completed work, we had a 13-day outage. Most of our neighbors were forced from their home. We stayed in ours the entire time. It was primitive but not terribly uncomfortable
Wow! That is a really high voltage for a gas generator. I assume you had to put in a transformer to step the voltage down from 5kv to 120/240V to power your house.
Lol.. honda makes the 5kw ultra quiet model. If they made a 5kv generator available to the public then youd have a lot more fires and dead people.. shit imagine pushing 5kv back through the main pole transformers.. my guess is it would hum for a second before it started doing those "womp" surge flash overs.. if you had a cap inline then a huge ball of fire would be included...
Am I the only one who loves how smoothly that dial turns? I could watch that all day!
It’s a little servo motor driving that
Right? Lmao
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The good one
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Relay clicking
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I did so much i just bought one 😂
Clive, I like your warning that if it wasn't approved by your jurisdictions and something went wrong you on the liability. There is a lot of things coming in from China to the US that's awfully smart if one only installs certified or listed products.
A very interesting and well presented explanation.....thanks. I have installed a manual change over system with manual interlock and have written a set of procedures to switch off load as I don't believe the Chinese breakers I bought can be relied upon to make or break load. So I change over off load.
I found your explanation of back feeding the 11kv brought back loads of memories as an Operation Engineer on the Southern Board' hv networks up to 132kv Now I am talking of the 1960s/ 70s !! The standard was to test and Earth the lines at all hv levels of work before issuing a Permit To Work
As indeed there had been fatalities. I recall testing at an old 33 kg sub station to find the back feed was from a neighbouring Lviv network back up through the 11 kg and finally back up to 33 kv.
However later I experienced amazingly scary hv practices in Canada and the USA ...but that's another story.
There's a certain element of heroic culture in the US power distribution system. They have a horrific fatality rate.
A widowmaker lead, priceless comment Clive . We call that a suicide lead in New Zealand. The risk of backfeed does exist. but Testing and Earthing is mandatory as well as using PPE. Normally a private generator
When we had a generator (US here), we had a cord hardwired into the breaker box that would plug into the generator. In the breaker box, there was a sliding metal plate that would block the breaker for the generator if the mains power was on, and vice versa if the generator was on, so that they can't both be on at the same time.
yup, they are still sold for each brand. the thing in this video is just a fancy version of that.
That plate is called an interlock kit that mounts to panel deadfront.
This is incredibly unsafe as the cover can be removed so there is the risk of unintentionally making it go incredibly wrong
Not quite what you are showing here, but it brings me back to my apprenticeship and having to manually synchronize three-phase generators with the main incoming 415 volts supply.
We, as in a VERY large factory and very large generators, would sometimes back feed AC back into the grid as a load test of our standby generators, this was all done with the electricity supplier's agreement and I think the company got paid for the electricity it supplied back into the grid.
While we were being educated on how the principle worked by sinking a small three-phase generator to the main AC supply, I remember one prat of an apprentice deliberately switching over when the generator/mains were not synced and boy was there a loud bang and the generator/mains fuses were blown, I don't remember what happened to the generator, but nothing good that's for sure.
With the very large generators, I can't remember how it was done now, it was 45 years ago, but the system we were being shown and educated with was using was very crude, but worked. There were three incandescent lamps, and all three lamps had to be of equal brightness before you threw the switch to sync the little generator to the mains.
I'm sure the very large generators were not synced by using incandescent light bulbs, but for the life of me, I can't remember how that was actually done now, old age catching up.
Regards,
K Watt
and yes that is my name and yes I was an electrical engineer
The device you're thinking of (to indicate whether 2 separate supplies are in-phase) is called a synchroscope. It deflects to the left or right if they are not in agreement, and points vertical if they are.
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I really enjoy your stuff Big Clive! Your explanations are always clear and unambiguous, and you manage to inject just the right amount of gentle humour into every post. I salute you!
My friend in USA bought a more expensive version of this and he has a pretty good diesel generator, and it does it's job and switches with quite a bang! It's well made and works great. Power went out...BANG....generator started up and the lights and everything else came back on. :) Power came back on another loud BANG from the changeover switch and generator shut off, the sound is because of the GIANT contact points in this thing it's no joke.
Interesting Video. In the USA it is law with most utility companies that a mechanical interlock has to be installed on a panel which is connected to a generator. The generator is generally connected to a 40 AMP or more breaker that is in one of the top positions. When mains is turned on the interlock prevents that physical breaker switch being turned on unless the mains power is turned to the off position on the panel.
The issue is these interlocks aren’t great because there are ways you can turn both circuits on as quite often you can remove the interlock or you can open the panel cover. The risk is a homeowner could try and fix something by taking the cover off and see that a breaker is off and turn that on when it is the main one and it’s being fed from generator. with a proper transfer switch it is a lot safer because the average homeowner would not understand how to dodgily bypass it
Love your accent, but even more so your calm and measured approach, which keeps your commentary interesting all the way through.
Could not agree more. 5****** to Clive.
Great warning. never thought of the danger from back feeding. This video should be shown to anyone who uses a generator for their home that was not installed by an electrician. Thank you. I know at least 3 people I will pass this on to.
The chances all you have never thought about the danger because you haven’t done it because the minute you’re holding a plug that’s going to become live with the metal pins you’ll probably think about
After watching this video I bought one of these and I must say it has worked extremely well. It is for my camper and switches between the solar system (inverter) and shore power. I forgot what the green terminals were for so I returned her to find out. Super glad I did. It is 3 years now and still works great. Not bad for $14.
Now I see that the green terminals are just for indicator lamps. Perfect. That will go on my control panel which is remote to the switch.
Nifty device! Bought a rather more sophisticated (and more expensive!) one from the UK, but it's still in its box. Far easier to switch off the incoming power, and PADLOCK the distribution Board! The keys to the padlock are on the same ring as those for the Gennie - so anyone HAS to stop the Gennie (key-start diesel) to get the keys for the padlock - pretty much a fail-safe arrangement.
They HAVE to stop the genny to get the key??... I don't think so. Some enterprising young spark could take the distro box key off the keyring with the genny still running :)
You need to superglue the keyring shut... or encase it in epoxy!
EscapeMCP - there's only the two of us, and The Mrs does NOT like fiddling with the generator!. The generator design is such that key removal can only be done in the shutdown position (basic safety interlock), and I've taken the "precaution" to run a few layers of heat-shrink over the key-ring - so surreptitious "removal" of the distribution board padlock key is challenging. There's also the added barrier of an NVR disconnect between the generator output connectors and the mains connect (our system is effectively a permanent install - no "loose cables with plugs at each end" for us, mate! :-D )
When I was growing up my dad backfed the house. He had a padlock on the breaker panel and during generator operation he kept the key on his person at all times. Not completely foolproof but pretty idiot proof.
I threw on a spare combo lock out of the kitchen drawer that nobody else but me bothers remember the passcode to
D3FTIGE KOST sure it would be, but back in the day having a set up like this was very pricey and most folks couldn’t afford to do things just because they were nice to have.
Do R/C! If there is one thing I have learned over the years it is absolutely, positively, to never underestimate idiots. They will make a fool of one every time if given the chance and are a reliable source of endless surprises.
D3FTIGE KOST ...and additionally, if I recall - houses used to have fuse boxes... ...where to disconnect the mains required physically pulling out something. Not sure what tech would've existed at that time for this; there may have been something.
Pretty idiot proof... unless your Dad's an idiot, that is (not implying that he is, but just pointing out a flaw in your logic) :)
For our American panels, you can get what is called a generator interlock kit, where you have the breaker from the generator input (and also a proper twist-lock male power connector on the side of the house that actually plugs into the generator), as well as a piece of metal that will go on the main breaker and the generator breaker, and prevent both from being on at the same time, so you can't backfeed and can't get a shock from the exposed metal on the male power connector.
This is incredibly unsafe because the cover could simply be removed where there is something unintentionally happening which then causes both supplies to be energised such as if you only have a fault and open the panel to meet some things there was a chance both supplies could be turned on
As far as preferred source, like you mentioned in the entertainment industry. Most decent, new transfer switches allow for settings that monitor the primary source (utility) quality. If it has transferred to emergency/generator after a utility outage, it will monitor the utility (for over/under voltage and frequency, as well as phase imbalance) once power is available again. Then once the power quality settings are satisfied, a transfer delay timer starts. If utility falls outside of those voltage, frequency, or balance parameters within the delay timer (say 15 or 30 minutes), it will reset the timer, monitor for correct quality again, then repeat the cycle.
You should keep the camera on any time you sit down so we can see you getting zapped
@firestarter5048 - I'd rather see you getting zapped
firestarter5048 He only gets zapped when off camera.
We don't have many power failures to worry about, but boats is need to switch from shore supply to generator and even a battery with inverter. Usually we get no more than 10amps coming in. The usual approach was to have three switches with a sliding panel that prevented more than one being used at any time. We would start the generator and warm it up before switching off the shore supply and switching on the generator. In the same control panel we had switches for all the loads. It was common practice to flip them all off before the switch over to generator, and then switch each back on in sequence, allowing each to settle before adding the next load. It sounds complex, but if you understood what was happening it soon became second nature. We would have to think whether we really needed the water heater or air conditioner or battery chargers. I love automation but sometimes it's sensible to make your own decisions.
Thank you clive. Interesting tear-down. I hope that who ever designed this one day sees your video.
Hi Clive, yeah we across the pond call it a 'suicide cord'. I do this Clive, BUT before I even go to
the shed where the gen is, I go to the pole and beneath the meter is a double breaker. I shut it off
and put a lock on the box. I also shut off MAINS in panel in house. This way there is NO way to
backfeed to the grid. ALSO some utility companies might decide to to NOT give service to
that house if they find a gen improperly hooked up, backfeeding into the grid.
Thank you, very well explained. Simple, plain English and a demonstration anyone can follow and understand 👍
This Tomzn transfer switch looks economical. I know installing a turn key auto transfer switch to your house is quite expensive and involve adding several more control boxes outside. In case you want to know , for Canada, the high voltages outside on the pole starts at 4160V, then double that to what we call 8000v and double again to 13 -8V etc. The dryer is not the biggest power outlet in most homes at 30 amps , most homes have stove outlet rated at 50 amps that we put on 40 amp breakers. But some who have gas ranges had the outlet removed or converted to a regular 120 V outlet. A gas stove still need 120V. In UK, when power is available (had to put that line in) it is 220 v with one line to ground, or neutral. In Canada , you need 2 live lines together to get 208 or 240 V The neutral is necessary if you want 120V from either voltages. Many motors or heaters will just work without the neutral. being a electrician for decades, it is against my religion to shell out big bucks for a transfer switch. I can use a "suicide" cord, or I just back feed the breaker, but I highly doubt I get zapped. Linesmen working on outside lines either assumed the line is live or they been grounding it for decades. It is extremely rare to see one of them hurt on the job.
I'd be worried about that relay being mounted hard against the PCB. Depends on the construction of the relay, but that's almost certainly a bad idea.
With the relay mounted hard against the board, even if it's a single-sided board, as the joint cools the relay pins will contract slightly as they cool. This puts strain on those leads which, in that style of relay, means it can cause slight contact misalignment and/or loosening of the entire structure. It also means (going by how you drew it) that pads on the relay base are in contact with the PCB leading to moisture traps (which encourage corrosion and fungal growth). Don't mount components hard against a PCB if you want the design to be reliable.
As an aside, wicking of the solder up the through-plated hole is not only normal, it's *desirable* in high-vibration environments because it stops both pushes and pulls on the component leads peeling the track away from the substrate. In aerospace applications you may find PCBs with all the tracking on one side but still using double-sided board with TPHs just for vibration resistance.
BTW, I find a good solder sucker is better than braid for removing components on double-sided or multi-layer PCBs. It sucks the solder through the hole, removing it from both sides of the PCB.
I've trained as a Canadian Electrician so I'm not familiar with the USA's NEC. In Canada, ALL Residential Generators MUST be connected to the Circuit Panel (Breaker Box) with an Interlocked switch that physically disconnects the City feed when the Generator feed is active. This prevents the Generator from back-feeding into the City Grid and thus keeps it from Electrocuting any Hydro Linesmen (the Electricians Licensed and Trained to work on the multi Kilowatt Power Lines). I believe the NEC has a similar Regulation.
Your videos are a great big manly comfort.
Happy to see that I‘m not the only old man still having the 12y old „let’s ripp it apart“ mentally. At least from time to time.
But at least for cars I‘m saved by a company car. 😎
I've got one of these auto transfer switches. I modified it slightly, so the green terminals on the bottom are to enable switching in either direction rather than output signals. I mounted a relay board right off the terminals and from there goes to an arduino outside of that box. this way, I can have the arduino decide when to transfer power to or from the generator with a delay. transfer doesn't happen until power is stable from utility or from the generator.
The delay isn't a bad thing, you can have a UPS to run your computer or radio transmitter.
The device in the video has me thinking of other application, such as off grid events such as Amateur Radio contesting.
one thing I learned, if you're using an inverter or inverter generator or anything that provides a clean and stable 50/60hz power, a normal ups should hopefully work ok. but, they can be picky. my backup generator isn't the inverter type, so the AC frequency changes with the engine rpm. a normal ups will switch to battery thinking power is unstable.
there's a thing called a double conversion ups. they use a bit more power, slightly less efficient, but they will take whatever power you give it, clean it up nice and pretty, and offer that to your valuable equipment. I got a few made by eaton, I found it'll keep using utility power down to about 60 volts and wont use the battery. because it's only getting half the voltage but still needs the same amount of watts/power for the equipment, it actually draws double the current at 60 volts. if I drop it to 55 volts, it finally switches over to battery. that's pretty neat. it takes the AC power from the wall, utility or your own generator or any source, it converts it to DC, then back to a clean stable AC. a normal ups only needs to convert DC to AC when it's running from battery, but a double conversion ups is always doing this the entire time it's on.
back to the thing about delay being a good thing, yup. when the generator starts, I don't want an immediate load put on it. likely it could stall out. at least give it a few seconds to come to an idle. that's why I modified my transfer switch to have inhibit relays controlled by arduino. I can monitor power sources and have a set delay. planned project, maybe will finish soon.
The issue is with external inputs it can be a lot less safe
@@UKsystems nope, can be more safe. depends how it is designed. in my case the relays inhibit the transfer by default. the auto transfer is not possible unless the transfer switch itself is ready to allow it, and the relay is activated to allow it. multiple fail-safes.
1. utility power needs to be cut
2. the backup power source needs to be ready to provide power
3. the manual/auto switch needs to be set to auto
4. the inhibit relay needs to be active.
if all these conditions are not met, nothing will happen.
I used to manage the IT operations of a small company that hosted everything onsite for compliance reasons. Our automatic generator cutover switch was poorly installed and almost never worked, probably the worst event coming when it couldn't make up its mind if the mains power was back up or not, leading to a situation where it just flapped between mains and generator until I manually killed the generator. Finally, after three visits from our "qualified" electricians, culminating in a full day-long shutdown of the facility the issue was resolved. These were the same electricians who wired 220 to an unmarked NEMA5 outlet, leading to my AC guys plugging a 110v appliance in to it and throwing a breaker.
Wow, in the US and have had a generator for years and not once have I thought of back feeding the entire house through the 220v dryer connection. Scary. And no, not gonna try it, no way. I'll let you do that one so we don't have to...
I tried it! (thrice actually)
I have seen a video with a pto generator feeding at the utility pole, guy switched off the power line, then had a three phase plug at the pole to power barns and the farm houses. Better that then feeding it through a dryer plug.
JamesAllmond what did you think? Power goes where?
It's only dangerous if you are a dunce lacking practical and common sense. Which unfortunately seems to be the majority of the worlds population.
Clive is right about it being fairly common though. It's something that happens nearly every time there's a hurricane.
I was just asked to do a video on the transfer switch for one of my recent backup power testing videos. I couldn't have done a better job than bigclive! Big thumbs up!
That's a genius of design.
Clive, I work in the Genset Industry, we would not allow that type as ATS without feedback validation to validate That the switches are in the correct mechanical positions.
That's one thing I want to buy. Not because I could use it but because the mechanism is awesome. The problem is 28 bucks are not in the price range of "Ill buy it just because" things.
I've lost 28 bucks in the console of the car after a few dinner drive thrus.
You must be a brokeass then
Im a student. But this is an equivalent for brokeass, so yes.
@Luca White Spoken like a true brokeass
@Luca White Maybe you should start doing better things with your life than replying to year old youtube comments
A great sports commentator is able to describe the action so well you can watch it on your radio, well you are that good, I watched the whole thing being away from the screen, by just listening to your great commentary! I’m sure the video is just as good! Awesome
When I build my own house, I’m totally putting one of these in there. Too cool.
I installed my own wiring and generator inlet and ran it to the electric panel with an interlock kit, you just have a metal plate that physically blocks you from powering the panel with the generator until you switch off the main. Simple and cheap like $45 or so and practically accident proof from back feeding. The down side is that the generator will not power on by itself when the power is out but for me it is a rare event to lose power, a bad snow storm in 2018 and 2019 left us without power for 1-2 weeks and always ready in case of an earthquake.
US is different to UK and most of Europe where DIN rail mains panel is common. Not seen any metal plate interlocks for them here. It always amazes me how much power distribution is overhead in the US, making it vulnerable to the weather. Japan is similar and some Asian countries are mind boggling with their rats nests of cables! The UK has a lot of overhead wiring too, but nowhere near as much as US. Germany has almost all theirs buried underground, even in most villages. Power outages are extremely rare.
In the US backfeeding into your home without disconnecting it from the mains will result in huge fines and possibly jail time depending on if you get caught. Though getting caught will be pretty easy with the new smart meters that consumers has installed. They monitor for blackouts and record if and how much power is backfed into the system from your house in real time via two way link. There is some leniency in the system for a noisy computer or sump pump backup or things of that nature where you might get a couple watts of energy, bot something large and they are going to send a hefty fine your way. We are in a trial area for the smart meters, they also have the added feature of daily usage reports through the online portal.
We are currently in a nation wide roll out program of smart meters here in the UK!
That's why the law states you must use an interlock or an automatic transfer switch to the mains to prevent possible back feed to the grid.
It would seem logical to put a generator transfer switch in series between the main breaker and the rest of the panel. That way if it trips, it effectively disconnects the mains automatically. I am pretty sure this is what those big commercial generator systems like the big natural gas Generac systems do.
Not really, simply switching off the main switch after the meter will stop it from surveying anything. In the case where the house is backfed from an internal circuit, the meter will not see anything.
I've designed, wired and tested dozens of changeover systems, typically 2000A 400V or 10kV, with up to 6 timing relays, voltage monitors, trip contact supervision, 20 aux relays.
This one is clearly done as simple and cheap as possible. Fun to see.
That's clever, and the use of ordinary breakers makes it quite safe :-D
No microcontroller or any other junk required :-D
zx8401ztv yeah, the breakers are essentially big limit switches as far as I understand.
zx8401ztv Save for their rather paltry 3KA interrupt rating. I know Clive mentioned a minimal interrupt rating of around 6KA for his country and here in the U.S. typical residential interrupt ratings are around 10KA for branch circuits and greater than 20KA for the main breaker. Which is to say, if they actually had to handle a dead short condition there is a real risk of the entire unit simply exploding into bits with possible injury and fire. As such they would need upstream protection to protect from severe short circuit conditions.
To me these seem more suited to dual utility feed connections where one has two incoming power feeds from the utility (such as from differing substations) as this automatic transfer switch does not actually provide for starting the generator nor does it delay transfer to, and away from, the generator to allow the generator time to start, stabilize, then assume the load as is typical of automatic transfer switches intended for generator applications. For this switch to really work with a generator "automatically" the generator would have to be on continuous standby and running 24/7, which is ordinarily only ever done in very critical applications (and even then it is common to allow battery or flywheel UPS power sources to support critical loads while the generator starts and power transfers over to it at which point the UPS returns to standby duty in case of a generator fault, at which point the backup generator is started and the process repeated, or to support loads while switching back to mains when utility power is restored).
It wouldn't even pass CE approval. The leds themselves poking trough on the front are litterally the only insulation between you and the mains... aside from the soldered connections on the breakers... This device is a nice idea and proof of concept, but that's about it. Not safe.
You fun killer LOL :-D
I dont need CE approval, british standards will do lol.
Ethan Poole the switch may be better suited to use the mains as the generator and battery supported solar system as the main power source .
Good advice to add extra 63 Amp MCB's in series with the transfer switch unmarked MCB's. It worries me that the manufacturer doesn't label those MCB's, they could easily be cheap unbranded knockoffs. We are talking mains supplies here so the equipment has to be safe. I prefer always a dead or zero position when changing over a transfer switch. (generator - zero - mains). With that double 3 kA rated MCB at the end, under fault conditions and arc flash could easily happen with serious burns to the unexpected home owner, who is usually not an electrician.
Technically this does have a zero point in the manual transfer mode, it's just unmarked and you have to be very precise to hit it :-)
I’ve always heard of the double male cords called “suicide cords”
In Finland they are called gay cords (accurate translation).
3:50 I'm slowly shaking my head. Why am I surprised though? People are amazing when it comes to "innovative solutions".
Wow I still remember watching this the day you uploaded it can’t believe it’s been that long already time had gone so quickly
this guy is awesome...a complete explanation of how these transfers switches work. this is where you learn!!!!!!! Thank you Big Clive from California
Thank you i have installed like over 40 but i never get intention to open it to see the mechanism inside the item. Watching from Kenya
I wired a farm building once using a 240-drop (out of the circuit box) and a 50-amp breaker. To resort to your 2nd input, you had to turn off the main, then turn on the 50-amp breaker (which acted as a 2nd main for the generator)...no harm, no foul, and gets around having to buy a $150 transfer switch....that said, it is NOT TO CODE in the U.S. (don't let an inspector or electrician see this barn-burner circuit!) A far-easier way to do this is to simply drop a circuit to a small box and use a 3-position rotary switch rated for the circuit to act as a transfer...which in circuit, would replace the breaker in my example. Again, MUCH TO BE SAID FOR RELAY-DRIVEN TRANSFERS where you have a 'dead pole' at midpoint, so that you cannot have BOTH SUPPLIES HOT at the same time (bad, BAD news for the power company, your home, etc....because they are not in sine polarity with each other!
The only thing I don't like about this unit is the "break before make" is very slow, it would be nice if it switched over quick enough for the devices connected to it would not lose power. However you could solve this problem by using a UPS (battery backup) in between the ATS and the connected devices.
Or a battery backed solar inverter designed to keep the interior power (to critical devices) operating.
If you’re looking at professional solutions, they’re going to come with a professional price tag. There are a lot of models now in a rail format that are on the 50 ms.
I assume for myself that transfer switches (be they manual or automatic) should at any means avoid accidental connections between power sources. So it is impossible simultainlessly cut off one input and get feed from opposite. There must be two-step sequence: break connection to the current input, only then make connection to alternate input, with some delay in between. Hager 1-0-2 switches works exactly that way.
Meanwhile, many popular chinese ATS produce just one loud click w/o noticable delay (8ms by specs) and they known as arc-prone with fried contacts in the end.
From this point of view that motorised "slow" model in this video appear to have rather right habit, first it momentarely turns down one break pair and only after that slowly turns up another break pair.
(Sorry for my poor English)
touching the leads while both the plugs are unplugged.... You're a daredevil! even though I'm quite confident in my knowledge of "low" voltage circuits and electronics in general... I'm always assuming that I'm delirious and that I might have forgotten to unplug it.
You might as well pull one of those "circuit breakers" to bits now you've already bust the circuit board for the relay .....
Wanted to say that I watch every video you make.... but the ones that include "(with schematic)" get top billing in that evenings selections.
Great video. Something that would be interesting to take a look at would be those 3000w 230v solar power inverters. Can they really deliver 3000w without noise etc?
I am looking for something alike, to install in my flat to power 3kW storage heater using night tarrif as main, and normal (day) power as backup. In my mind backup will always be on, but "night/main" power will be switched. Great videos Clive, like watching and picking up knowledge.
I was thinking about how that transfer switch could have a breaker instead of just being a switch myself because the motor wouldn't necessarily allow it to turn off. It dawned on me at the end of the video that, in the event of an overcurrent, the breaker would move to the trip position and not the full off position, which of course, theoretucally, wouldn't affect the position of the motor arms at all.
You also have the phase shift. Most standard generators do not try to sync the phases. So then you normally have a boom as well.:)
Phenomenal as ever Clive. Love your teaching style.
Great video. I just might buy one to play around with. I do wish you had dismantled one of the switches to see if a) these are circuit breakers or just switches and b) the contacts are even close to adequate for the current rating. The Chinese are notorious for claiming a 20A switch contact can handle 40 or 60 A. Of course, they soon burn up.
You must have come across JIS screwdrivers, Clive? Japan Industrial Standard. Much better fit for far eastern screws also work well on Philips screws. No climb out. You can get Vessel brand JIS drivers of all sizes on Spamazon. Not cheap, but a real investment.
Very good. Surprised no one else caught that. I think it's got the small dot indent on the face of the screw...which I think I saw just now.
bigclivedotcom ,
Had to pause at ~ 5 : 00 and compose a comment here - from across the pond - to say that you are another one of those high value propositions, high ROI of my time watching your videos - right up there with Techmoan, the Essential Craftsman and so many others I'd have to take more time to recollect; yet, and still there's not seemingly enough of the like and wanted to tell you your content and its presentation is top notch as I don't give a hoot about production value near as much as the message content and spirit, diligence on practice of topical scope and relevant theory infill , perspective and therein a richness and whether or not I came away a better mind for the experience.
Can't say enough without droning on - thank you! I appreciate your preparation and explanation / teaching methods!
I wish that you had pulled the breakers apart to see whether or not they were indeed MCB's or not. I shouted at my screen, but I don't think you heard me. :(
Yup :-)
I doubt they are MCB's. Every ATS I've installed (100's) doesn't use breakers, just isolaters. Protection is done from the main board and from the gen source.
So relevant now!!! There are a bunch of these on ebay. All look like 63A! A lot of folks are gonna be running their generators this winter when the blackouts and Brownouts kick in. Welcome to 2020+2!!
You raise the issue of backfeeding the incoming supply from a generator during a powercut. Of course, sometimes this is desired - eg solar panels or other local generation - so are there systems which will prevent these from feeding in when the mains power fails? But of course it would be neat to continue to be able to access any power they are generating despite the mains supply having been dropped.
Inverter chargers can do this, they act as a mains grid that will take excess power and charge batteries which also completely isolates the 14kv residential lines eliminating a potential death shock. Most, if not all solar inverters have island protection which means that if the sine wave of the grid disappears the inverters do a safety shutdown.
The problem with anti-island protection systems is that if you DO have a mains outage, your Grid-Tie inverter stops dead. So, even if you've got solar capacity, you can't use it. There are ways around this - our strategy is to isolate from the Mains and use a standard (no Grid-tie) inverter to provide power. Once again you MUST ensure isolation from incoming Mains, and therefore you MUST have some form of fail-safe disconnection system or protocol (for equipment and safety reasons!)
our solar roof setup (7.5kW peak) turns off if no 50Hz Sine, or difference to 50Hz is more than... 0.02 Hz i think it was ??
Only Necessary power needed here would be for central heating (+ cooking).
Warm water is mainly gas, secondary electric heaters.
I cant remember having a power failure at home in years, even then it always was over before you knew what happened,
AND the one failure i got at work (street working company dug into main line)
was fixed within 20min before the "manual generators" were connected properly... (Thanks to isolated subnets with multiple feeding points)
BigBoss was making everybody stressed for no reason (phone lines only work a certain amount "off time" via local backup in distributor anyway)
And when (very small) Gen was hooked up to main server running (unloved old usv starting to run low..), he plugged in shitload of unnecessary things (phone, PCs...), so the generator shutdown with overload.
If we just went for a walk 20 minutes, all would have been fine after that.
But then all Server and Phone and "Stuff" had to be replugged where it was originally, and it took over an hour until normal state.
...You wont find a single power line sparking for more than one " lightning arc" here if ripped off, without anyone needed to shut it down.
our solar roof setup (7.5kW peak) turns off if no 50Hz Sine, or difference to 50Hz is more than... 0.02 Hz i think it was ??
Only Necessary power needed here would be for central heating (+ cooking).
Warm water is mainly gas, secondary electric heaters.
I cant remember having a power failure at home in years, even then it always was over before you knew what happened,
AND the one failure i got at work (street working company dug into main line)
was fixed within 20min before the "manual generators" were connected properly... (Thanks to isolated subnets with multiple feeding points)
BigBoss was making everybody stressed for no reason (phone lines only work a certain amount "off time" via local backup in distributor anyway)
And when (very small) Gen was hooked up to main server running (unloved old usv starting to run low..), he plugged in shitload of unnecessary things (phone, PCs...), so the generator shutdown with overload.
If we just went for a walk 20 minutes, all would have been fine after that.
But then all Server and Phone and "Stuff" had to be replugged where it was originally, and it took over an hour until normal state.
...You wont find a single power line sparking for more than one " lightning arc" here if ripped off, without anyone needed to shut it down.
A pure sine wave inverter will run a fridge or any other induction load just fine.
Modified Sine Wave inverters cause motors to struggle, however.
I’ve done something similar with a solar water heater changeover switch using two motorised valves, to switch between a combi boiler and a solar heated water tank dependent on water temp. My relays are off in the default state which is predominantly solar tank is hot and I can turn off all power to save the relay coils. I also have a manual override for winter.
I think the design of the power transfer switch could be improved by only energising the relays when the generator comes on, and use a normally closed relay using no power when on grid power.
Love your tutorials btw you’ve been an inspiration albeit mostly above my level of knowledge.
Great idea! I'm just about to do the same thing: a motorized valve that can select either my solar hot water or a new propane tankless water heater. The valve will be controlled by the mechanical thermostat on the solar hot water storage tank. I'm confident it will work just fine. And as you point out, I can control the valve manually to save the relay coils.
Very cool device. I have no need for it, but I want it 😜😺. Another very interesting video
a neat trick for hot melt glue that's in hard to reach places you can't apply much force or heat is to give it a shot of freeze spray
makes it hard as a rock and allows it to crack off the surface of things easier
where is the other video gone? I just watched it half way through...
yeah, its gone O.O
what was it even about? only saw the title lol.
He made a pcb by himself, it was for a emergency light ^^
It wasn't supposed to be released yet as I hadn't actually added the text yet. I uploaded it as private and it appeared as public. It will be released in a couple of days.
Already seen it Clive! *evil laugh.
You could try two red LED to clamp the voltage in stead of the zener...
"This is neat so far, I am liking this inside"
Yesterday I was looking for a schematic of these and today you put up a video about them... Coincidence?!?!
We just lost power in my house, and we had to manually run an extension cord from our generator to a power strip in the kitchen which we plugged the refrigerator to, and then we ran an extension cord from there to the freezer across the room, and we had to move the microwave to plug that in, and had to get a standing lamp for light, and everyone had to be in the room to charge their laptops and phones, and it was aweful, so sad. We need to get one of these, but unfortunately I don't think our insurance will like it if we got it from eBay.
XDSDDLord
You can plug the generator directly into the house. You need an extension cord with a double male end, turn off the main breaker, turn off breakers to non essential parts of the house, and turn off any non essential devices, then plug one end of the cord into the generator and the other into any standard outlet and it will power the whole house. Be careful to not overload the generator though.
darkworlddenizen yeah but dont forget to switch off the main breaker as you won't supply your neighbors house :)
Yeah..exactly thats the way a unwary person does it "extension cords", and now even gets proposed to build and use a widowmaker.
Because people need to use life essential things like mobile phones and laptops 😬 to survive.
any transfer switch will have to be inspected and approved by your local electric inspector,otherwise if you do have a fire or whatever your insurance is not obligated to pay.Cheaper in long run to have it done right
XDSDDLord Proper manual transfer switches are not all that expensive and are well suited for manually started generators. There is really no need to go the questionable China post route when you can get a perfectly compliant manual transfer switch for a reasonable amount.
I live in upstate SC where ice storms are not at all uncommon (typically one or two every several years) so we have a 15KW generator and a 200A transfer switch installed just in front of our house main breaker panel, allowing is to choose which circuits are generator powered by selecting which circuits are switched on in the panel with a watt meter displaying the load on each of the 120V legs so that each leg remains within the load (6,250W) the 50A circuit breaker from the generator will support without tripping. However, you can buy ready made generator subpanel that are reasonably priced that will support up to a dozen, or so, circuits throughout your home when on generator power and are easy to install once you choose which circuits you consider critical.
Two things I'd love to say, first is that Clive is my hero, and I learnt all my electronics through this channel, especially the Fanny Flambeaux doll vid. Second thing is that I have a 4 pole contractor with mechanical and electrical interlock set up, and I run the outputs into one of these Tomzn mechanical transfer switches, but a 4 pole version. The contractors change over is close enough instant, but with this Tomzn unit inline, the delay is increased and also, if the breakers failed, I'd rather that then a sticky contractor. Love this unit, and I love the simple wiring on the output indicators. I had to watch this then ask when you join the output contacts together would that back feed the indicator for the mains but the relay solves all that gunk.
Good work Clive...
Could a guy use a double pole double throw switch ?
By connecting the two ( P ) terminals to the INPUT side the the breaker box, and then connecting the two ( T 1 ) terminals to the main feed coming from the pole transformer, and then connecting the two ( T 2 ) terminals to the generator. That way the house can only be feed by either the mains or the generator,,, but not both...
I was going to do this to feed my furnace. I have a 3kw inverter, and a very large motor home battery. But , alas, , once I figured out that it could be done,,, why do it...
Keep up the good work. ..
Something like this?
www.dhresource.com/albu_292093706_00-1.0x0/63a-double-pole-double-throw-knife-switch.jpg
Ooh, nice! Does look a bit shoddy round the edges though, like typical Chinese shite manufacturing. Like bits are going to fall off, and the thin plastic case is gonna crack quickly.
If you had a well-made version of this switch, I'd want it. Dunno what I'd actually do with it, like. Just use it as a light switch I suppose.
RDJim
Not seeing the internal workings it us hard to tell if it would be heavy duty enough. But by the description in the title that is what I had in mind...
But to actually do this to the whole house,, upon further thinking, I would use a triple pole double throw switch...
I hope this helps...
But at any rate,,, I am guessing that for insurance purposes you would need an electrical contractor to sign off on this installation.
It's quite common in India, sold for 2-4$ for 30A
Wily Bee, A transfer switch/relay is normally just a big double throw switch or relay. In the switch, there normally is a center off position also. In the relay setup, it can be done with a single large DPDT relay or two single throw DP relays. In three phase setups it almost always is done with two 3 pole single throw relays with a delay circuit on them. The tranfer switch on the side of our house is one that is DPDT Center off but has the ability to have another set of contacts added to use as a 3 phase unit. It is currently fused for 200 amps 240 volts but can take up to 600 amps at 480 volts. When you throw it, it makes a very loud thunk and the lever part is over 18" in length. It is lockable in all positions too.
Liking the fact it uses a motorised manual switch. The ones i've studied in the past use interlocked contactors and i didn't like the fact that I had to rely on a contactor being energised all the time for normal on mains supply - despite working in IT where such devices protect significantly more important stuff than my house! I went for a manual changeover in the end for the sake of simplicity and avoiding spikes and surges swapping between genny and mains.
Eliot Mansfield This one still has an always energized coil. And the mechanical interlock is incomplete if that motor stops halfway through (as briefly spotted but dismissed as "will never happen"), even more likely in manual mode. Anyway, I think all these "two-breakers and lots of mechanics" designs for transfer switches are just stupid with too many things that can fail and overcomplicated user instructions. A properly overbuilt break-before-make changeover switch is a much better starting point for designing these. Automatic changeover would just move the one 4-pole/3-pole/2-pole switch, not try to dance around two switches.
got a vid notification went to watch it and its not there ? im confused what happend?
it done gone
UA-cam released a video uploaded as private before I could complete the associated description and data. It will be released properly in a couple of days.
bigclivedotcom ah ok I gotcha thanks for straightening that out now I'll be able to watch the change over switch video without thinking about the other vid and to what happened thank you for my peace of mind lol
Now we're on pins and needles....
bigclivedotcom I feel slightly cheated lol. Now what am I going to watch during the night. Guess it will be old videos of yours 😁
Clive, thank you do much, nice to see the detail in it, nice and neat little design. I really enjoyed the The breakdown of it, And yes the case was a joy to watch come apart with the removal of the keystone screw.👍
Oh and I might add there was a day of power issues a while back that had people coming into the supply place where I worked and asking for a heavy double male plug for their generator. Their anger and hostility that we didn't have one on the shelf was amazing to me, because I would've never done this, I was a bit oblivious to what they were doing Until I worked it out later. But in the interim I stopped explaining any of it to them, and just suggested they talk to an electrician. The guff I took from them was amazing, and pushed me into a posture that if they were too stupid to figure out how to build the cord, and we're angry because we didn't start such a thing, I wouldn't tell them how to do it, and ended my assistance. Sometimes it would come Knowing they shouldn't have such a thing or do such a thing, I will try and avoid telling me what they were doing. They really didn't care about the workmen, and weren't smart enough to shut off the main.
Serve like an old boss of mine the thought his friend was such a genius because he where is his garage with the supply from the house as a single wire (single conductor), he thought the guy was genius, when in reality is money saving technique ordered on some insanity level. All it takes is one loose thoughtless day of him Dragon aluminum extension ladder through his yard or or some other site not realizing that electric mouse trap was there waiting for them and Presto, dead guy.
Thanks Clive, another great video.
speaking of breaker failing dramatically ua-cam.com/video/gOUSDDLKICk/v-deo.htmlm30s
That's one of my favourite "Mike-moments".
I use one of those together with an UPS to supply power to light, fans and fridges in my apartment in Kenya.
an apartment is relatively easier to maintain as it is smaller
What did u do to ur thumb? It keeps distracting me 😂
Work related impact. It'll grow out.
I guess he got distracted and his thumb reminded him to focus on what he was doing 😅😨
On boats I just use one relay with 2 x NO and 2 X NC. The two NC contacts are used for the inverter power, the NO are used for shore power. In also feed the relay coil from the shore power. This makes the ship run on its own power unless the shore power is connected. Switches fast enough for computers to keep running.
What happened to the other vid :(
Misfire. It'll be up soon.
premature epublication? are there pills for that?
Colonel Sanders damn i want some kfc now
I'm with you on the always-powered relay; not something I like to see in practice, when some logic (µC or other) can accomplish the same thing, using a lot less power.
Chinese characters and safety equipment. Those don't go together. I wouldn't install that in my house.
Have a look at the Hager double pole change over switch. In industrial situations. A-B relays are used.
If you use the wrong plug, You turn into fanny flambo. LOL
In the US, if you've got the right kind of breaker panel, you can get a mechanical interlock which mounts over two breakers. One breaker is the main utility and the other is for the generator. It prevents both from being on at the same time and thus prevents backfeeding. Very inexpensive compared to proper transfer switches which are quite expensive. I can't use one, so I just use 12ga extension cords for fridge, microwave, lights and electronics. except for my gas hot air furnace which has a small transfer switch.
The single phase test leads you were using to test that transfer switch are called "Death adders" here in the land downunder.
I like it just that it does not have that circular plug where you can plug another battery or your ev etc. Also I would love to be able to control which of the items plugged into my solar are off but then again just turn them off at the wall.
What do you think
One of my jobs many years ago was pat testing within the company .in one department was a very nicely made bench on wheels so it could be used within the lab.Anyway pat testing must have been lax in the past because when i unplugged the plug connecting it to the mains (it in reality was just a extention lead but with conduit feeding several sockets along the back ) i unplugged it from the supply and plugged it into the pat tester and everything went black!Once the power was restored i noticed the problem the designer had in his wisdom fitted a clone lead on the other end !!!!Ofcourse i was lucky i didnt inspect the first plug or i would have found to my dismay the pins would be live fed from the other plug .Repremands were made and i left with 6ft of wire with a plug on the end and the knowledge to look a bit harder in the rest of the building
Thank you so much for the precise to-point informative orientation. Can you also do the practical video clip of the wiring process from the panel control to the generator auto battery connection for ATS
The break before make design both ways is because AC phase difference will make something explode if the generator ever gets in parallel with the mains. The circulating current will be huge before the generator locks into phase if it is even designed for use in parallel.
A generator accidently tied to the utility power will almost instantaneously trip the overcurrent devices because the amperage will be sky high for milliseconds. It cannot continue to operate. Nothing will explode.
My grandparents backfed (probably still do) their house through the 220v dryer plug here in the US. I was taught once when there was a power outage to disconnect the main breaker to keep the generator from blowing up.
A $30 interlock device makes it legal in the US, it simply doesn't allow generator fuse to be turned on unless main is off.
you stated an inaccuracy that in the USA, the 30A dryer outlet is the highest power connecter. we also have NEMA 14-50 (50 amp) and NEMA 14-60 (60 amp) outlets. this NEMA 14-60 is our highest power *2-phase* outlet & plug. but the 30A dryer outlet is *commonly* the highest power outlet in some homes. (but this is only with homes with an electric dryer. gas dryers are very common too, which only use 120V circuits.) But now with more popularity of Electric Vehicles, more and more homes are getting wired for higher power & higher amperage 240V circuits.
Searched UA-cam for your video on this transfer switch. (bought one on Amazon from china, curious to how its engineered) sure enough here it is. Thanks for saving me the trouble of having to send you one for a video 🤣
I'm curious to the draw from the relay. Because I'm using battery/inverter as the main ac input, and my shore cord/gene is going to be wired as the backup.
Since the relay coil is always powered if main input has power (by my battery Bank/inverter) I haven't yet installed it, or my smartshunt would tell me the draw and I wouldn't be typing this lol
Two drawbacks of this circuit:1. LEDs could burn out in short time because of reverse voltage of 300 volts. There should be silicon diode in series to prevent that.2. I've been taught that you should never put two different high-voltage sources to the NC and NO relay contacts. There is possibility that arc which arises between moving contact and NC would extend to NO and stay there until something burn out. These relay contacts could be arranged in safer way probably.
AllMyCircuits Given that the Chinese often use/produce custom silicon or make careful device selection where such will lower production costs by eliminating components, it is very possible that the LEDs consist internally of two back to back LEDs that effectively limit the peak reverse breakdown voltage seen across the reverse biased LED junction with each half cycle. If they never see more than ~2V when reverse biased then no breakdown will occur and thus no damage to the LEDs over time. This would also greatly reduce perceived flicker since their flicker frequency would be twice the line frequency. Such are effectively identical in construction to ordinary bicolor LEDs, only in this case both LEDs would be red.
As the new clive's video states, that's not the case: they just use old-type LEDs which tolerate reverse breakdown pretty well (at least when we conduct less-than 1 mA of current this way) so the continue to work for quite long. Doesn't work with modern ones though...
A bigger potential failure point would be mechanical. If the switching mechanism breaks, such as having the plastic switches break, then it could potentially have both mains power and the generator on at once.
The covers do protect against foreign objects getting in the way, but it also means you can't visually see how the switch looks.