Great deep dive! Seeing how the different phases interact like this in the case of a broken PEN connection is fascinating. Hidden complexities in such systems
Something I think was worth a mention is that we are no doubt going to see manufacturers take the cheap way out and use an earth reference probe, if the soil arround that probe dries out or the probe is disconnected then the voltage fault on single phase wont be detected. The only method that can be trusted I believe is measuring for fault current on the CPC. 20ma is a good threshold for this as the output will only trip if current is shown on the CPC. I can see this voltage detection via a reference probe being a problem and even giving nuisance trips.
If you simply have an earth rod in place connected to the MET of a TN system, does an EV charge point have a TT supply or does the TT have to be seperate of the MET?
Best explanation yet , bar putting impenetrable barriers around your vehicle every time you charge it up this is as safe as it gets at the moment . Even with the latent risk of injury or death still a very small risk . Makes toasters and wet or damaged extension leads in the garden seem nuclear 😂
Great video. I guess we are lucky here in the US, as our chargers don't use neutral and only take the two split phase conductors and safety ground to the chargers. There is no neutral line to get lost! 😎 The newer chargers have GFCI protection built in.
The charge is grounded and the ground wire is the PEN (Protective Earth Neutral) outside the main panel. As long as you have anything connected to the neutral it is a risk. The fact that US uses ground rods and the lower voltage helps somewhat. A GFCI does nothing to protect against a PEN-fault.
@@okaro6595 Yes I know, however we have no neutral to deal with for the EVSE. Because we use traditional single phase and use split phase, we only bring out L1/L2 to the chargers (240VAC), then safety ground. So we can't have PEN fault with EVSE, at least level 2 EVSE, is what I am talking about. The only time we use neutral are for 120V circuits.
What a useful video. I get a free BP Pulse home charger with my new EV but I think i will take the alternative 2 year subscription instead and pay for a Zappi When I get my drive done should I have an earth grid installed under it? Does it need to be stainless steel of at least galvanised?
I was watching this and trying to understand Indent 5. As I understand it, the Zappi was sitting on L1 and N, the PEN fault was introduced. Then, the Zappi was tripped when around 19ma of current flowed down to real-earth. Given there is a PEN fault present, that only way the Zappi could possibly detect that is to detect the current difference between L1 and N, so why is that anything special? that to me sounds like the exact description of a 20ma RCD? What am I missing?
@tim g I think what Chris is describing though is they are detecting current flowing through the CPC (earth) that is connected to the car, so while I understand an RCD in the fuse board would not trip, what the Zappie is doing, as well as the voltage check is simply the same as an RCD would do, but instead of looking for a fault current in-balance between L&N back to the board, its relying on the fact that the fault current would go through the CPC to the car, and through the person touching the car. In effect its still just an RCD but in a slightly different configuration and instead of measuring an in-balance between line and neutral its relying on sensing a current through the CPC that is going to the car its self. So if you are only looking for a 20mA fault current (as opposed to low impedance path to real earth that an earth rod would provide), it seems that you would get a far better installation of you had a reference earth rod, only needs to be low enough impedance to present a fault current. I would rather that than rely on 20mA + flowing through one of my children for 5 seconds before the fault current trips the protection
@tim g depends, many properties have old steel or even lead armoured cables where the sheath is the earth, which, makes contact with the ground it is buried in, and of course, in the event of an upstream PEN fault, this makes the real earth ground live. Sticking an earth rod near there would not be helpful. So yeah its not always simple to find a decent place to put an earth rod, I think the regs say something along the lines of 10 meters away from any services. In practice, in my house, both the gas and water come in to the property in plastic, although my electricity supply does come in on an old lead 3-phase 100A feed. For houses at least in the UK, services generally come in to the front of the house, so the back garden is generally a good place to site an earth rod. As you not always simple, but still very doable when you don't need a low impedance path, at 240v even a ground reference with a 5,000 ohm impedance to ground earth will give you a fault current in excess of 30mA - more than enough to trip. I understand why spraks don't like installing them, but there is no doubt thats better than creating a fault current through one of your children :)
@@gerrysweeney Earth rods can be unreliable and, especially if there is a PEN fault leading to large currents flowing through the earth from things like underground pipework bonded to CPCs and the rod is anywhere near those. There's a lot more to this than simply banging a rod into the ground. Whatever buried services are around can play a very big role in this, especially under fault conditions and it's often difficult to establish what might be there, especially on older buildings.
Install a foundation earthing under 1 Ohm, connect it to PME bar into your house, and you will never have problems from broken PEN conductor out on the street. Here in Greece foundation earthing is required in all new buildings from 2006
A great insite from Gaz and Dr Chris. For those wanting more information on how the faults could occur and effect all types of installation watch the same subject by John Ward
In the US, practically every charge point (EVSE) has a built-in RCD (GFCI), for the past 10+ years. Interesting that this is "new" technology in the UK, especially since RCDs have been used for a while. I can't imagine Dr. Horne would have been the first to think of putting one in a charge point. The regulators should just require every charge point to have an RCD built in like the US, and get rid of all those other silly regulations. It's also strange to think that UK houses have only just started to use supplemental ground rods to protect against neutral faults while in the US they've been required since 1978.
Hi, great video. Can I ask why PEN fault detection/protection is not added by the DNO before entering the meter? If there is a PEN fault, wouldn't we be just at risk from touching any bonded metal in the house too? Sorry if stupid questions, I'm a newbe.
@@efixx I worked it out 😄. If they fitted PEN fault detection at the meter box the a PEN fault would take out whole streets. So, they reckon so few people would be at risk the put the onus on the individual. Just my hypothesis though!
That’s good. The PEN fault causes charger to stop so go indoors to make a cup of tea and when touch the tap or metal sink or radiator you get a shock! Would it be better to protect whole installation from PEN fault?
I believe that’s one of the reasons why things like metal water pipes, metal gas pipes and other extraneous conductive parts are connected ( bonded ) to your earthing point in your house, or should be.
SIMON HOWARTH yes bonding helps in certain circumstances. However in a supplier side PEN fault that this scenario covers, the bonding acts as an excellent conductor to make all of the connected metalwork in your house live, most probably including your brass outside tap! This video covers an approach to resolve that very dangerous (but unlikely eg approx 500 per year in country) fault scenario but just for ev charger not rest of the house. Incidentally, I am no expert and uncovered this as I was researching what I need to do with bonding in my house when I do some house refurbs, asit has changed since I was a sparks prior to 1990. I found some excellent videos including this one and also a variety of electrical instructional videos by John ward where I saw the pen fault explanation, google him or flame port, his website.
@@marke8732 That is the point of bonding. To equalize potentials so you will not get a shock between an appliance and the sink. Sure if you stood in wet floor bare footed that would cause a problem.
One would expect the risk factor relating single phase to be expressed as a ratio of reported faults to total installations. This would not artificially reduce the “risk factor” simply due to the number of installations.
Good video. Just one point if you could clarify. Chris explained that they have a built in RCD so no need to install one in the DB if not buried on plaster (i.e. wired in SWA clipped direct). How is that RCD reset? I didn’t see that it was a user operated device. Does the charging unit reset it internally, if so, how? Does it have a test button for 6 monthly operation? Also, you were tripping out on 19mA as opposed to the 30mA we would normally install, so surely wouldn’t hurt to still have an RCD at the board as the two would discriminate. Also, is 19mA a bit low for a trip, would it be considered a nuisance trip?
RCD's are mandated to trip in the range from 0.5 up to 1.0 times the *nominal* value of residual current. If a RCD is marked with 30 mA I_delta_nominal, it must trip in the range from 15 to 30 mA. Thus 19 mA is a valid target to manufacture for.
They demonstrate a reset by the user, in the video at 16:51 . The product is made with sensing separate to contactors/relays (that "energises" the cable going to the EV/the 'type 2' connector), and the relays are controlled by the embedded microcontroller. So a reset is done via the electronic control panel It does have some form of self-test.
It doesn't need a test button as it can do an RCD test every time the car is connected by injecting a current into the sense transformer ( with a seperate winding) before turning the output on.
It was also measuring the earth current rather than the line and neutral current imbalance, which would be equal if there was a PEN fault. Watching the e5 group opened my eyes to earthing etc.. You could even have a scenario where 3 houses fed by different phases are off one cable, losing the PEN near the origin would mean all the neutral currents in all 3 houses could flow through anything that is connected to the mass of earth, a metal water pipe etc. or a person touching a charging car
Please correct me if I've misunderstood here, it detects a broken PEN Earth gone and still continues charging the EV/car with the car body above 70 volts, crazy, should trip and stay tripped once it detected PEN fault. Surely hi-tec can come up with something smarter than this.
Great video still not sure about EV chargers I think it should be a specialist job for people who have been trained purely for installing EV chargers? Great video Gary, thank you
The video seems to be saying that this setup is fool-proof and can be installed by a builder who's done the full 3-day NICEIC qualified electrician course.
Silly question but , in a tncs system if we lose the pen conductor how we manage to still have power? How the circuit is closed if neutral and earth is cut?
The current which normally flows down the PEN can take various routes depending on where the break is. e.g. via other houses on different phases, down earthed service pipes (gas or water) and other equipotential bonding or supplementary earth electrodes. See John Ward's video "TN-C-S Danger - Broken PEN Conductor (Combined Earth & Neutral)".
Hi Gaz, posted this on a few videos and never got a response, do I have to finish my install completely to pass the install or does it just get marked on quality of work in regards to the AM2? Thanks mate
Hi there, Im getting my first EV, a model 3 Tesla, and have purchased a Tesla Gen3 Wall connector. Do I need to fit PEN fault detection between the wall connector and the distribution board?
Is not just a risk of electrical shock but all electrical equipment will suffer from over voltage so it will become faulty. It happened to me when neutral accidentally disconnected in CCU. I have 3 phase in 4 stories building split in 5 flats and in couple of flats all electronic devices was burned. So i installed in between metter and ccu o-pen monitor. Because I have 3phase I able to make my power network super safe compare to single phase.
So what about if I happen to be digging up my drive anyway & want to go the great big earth mat route? I am finding it very difficult to find guidance/help on doing this, even by trying to involve companies that you might expect to know. I am interested from the perspective of going off grid in a power cut as well as the EV side. How big does the mat need to be for example? Would a condudisk or multiple condudisks serve instead? Does the mat need to go all round the house as the next proposed set of wiring regs confusingly seems to suggest?
An 'Earth Mat' is just a term. You can create a Virtual Earth Mat by sinking Earth Rods and using the Ground they're sunk in to create the Virtual Mat. Basically the Ground connects them all together. You might get away with just one Earth Rod on a 'Domestic' type installation, it all depends on how well your Ground conducts electricity. Keeping things simple here, You would sink test earths rods around your property and measure the resistance to your main Earth Rod. A bit of Ohms law and Hey Presto you have your Earth Mat. Imagine your property built on a Salty Marsh compared to one built on dry gravel and rock, which one would have the lower soil resistivity ? You could also dig a trench and lay a long galvanised pipe in it etc. Loads of ways to create your Earth Mat.
Regardless of what the regs say, if you want to make it safer, install a ground rod, and connect it to the CPC inside the Zappie at the car side, that way, should there be a pen fault event, your earth rod would provide the path to real earth for the fault current that would trip the Zappie, and that would save one of your family having to touch the car to create the path to earth... Thats what I think anyway...
I'm not sure from this video whether it takes someone touching the vehicle after the earth PEN has failed to cause the Zappi to trip or does the Zappi immediately trip once the earth PEN fault has been detected without someone touching the vehicle?? if it takes someone to touch the vehicle in order for the Zappi to trip then the vehichle body could be sitting there potentially live??
That seems like a clever bit of kit. I can imagine the headache of going out to nuisance trip, and trying to ascertain the cause of said trip! When the 18th edition first came out (before the amendment) I’m sure it said something about electrical separation being a solution in this scenario. Has this now been removed in the amendment? Even though you’d need a pretty big isolating transformer, I thought this was a really good solution to this type of problem? Great work Gaz👍
Nice to see the cleaver people from my energy. I’d be annoyed if I woke up to find my car still had a low battery. Could it not try and reset after 2 hours and see if the fault had gone? (Ie false trip)
It's not clear why this is a particularly innovative solution. It seems to be a simple voltage comparator and RCD. It looks like it covers all bases, but why was it causing headaches in the industry?
It's just that it wasn't previously required. So it's just a complaint about doing something new or in addition to existing implementation requirements.
@@thomasbonse I don't understand your reply. Can you re-word it? I'm also thinking the detection of CPC absence might be the clever bit. RCDs are usually blind to PEN faults because the shock current has flowed through both the line and neutral of the RCD sense coil i.e. no imbalance is detected. I wonder how they've solved that. There's a nice illustration here ua-cam.com/video/JRHyqouJPzE/v-deo.html&ab_channel=JohnWard
Regular RCD's are sensing current in live conductors (meaning lines/phases and neutral conductors), and that is fine for faults where live parts make contact with earth/PE/CPC-connected metalwork. When a PEN breaks, the dangerous current can flow from the PEN (on the side of the break that is detached from an earth electrode) to the PE/CPC to exposed metal and through a person to earth ground to return to the supply transformers earth electrode. As this does not create an imbalance in the currents on live wires for a regular RCD to detect, PEN faults need a separate current sensor for currents in the PE/CPC conductor to detect these fault currents. In short one RCD on all but the PE/CPC combined with current sensing of the PE/CPC alone combined with voltage sensing. I don't know why ready-made (all in one with regular RCD protection) PEN-fault detectors were not generally available before. Too few requests? The headache may have come from the lack of explicit permission to rely on detection of fault current in the PE/CPC (when voltage between line and neutral is within range), and the lack of availability of suitable components for PEN-fault detection and full disconnection of all wires.
before we had RCDs didn't we have kit that detected leakages on the earth conductor, seems the same idea, detect that then open all the circuits (including the PEN)
Eugh, TN-C-S causes sooo many problems. Sheer laziness by the DNO's :( Whack in a rod. (difficult in some modern estates to avoid the existing utility lines though :( )
All standard car charges have a pin to ground/earth that is connected to the chassis, even if the charger inside the car isn't using it. Look at the pin-outs on a CCS or Tesla connector.
Great Video! Although it seems that a man, woman or child needs to receive a shock of up to 19ma to trip the unit if the voltages are within the 12% range under fault conditions. Is that super safe? If so surely a demonstration could be illustrated without the box of tricks with variable impedences?
But there is no way currently available to trigger a trip without someone or something directing current to true ground creating the imbalance, some people can be adversely affected at these low currents even fatally ,a practice test could still be dangerous . If the imbalance is set much lower the risk of nuisance tripping will be more likely. It’s the old bird on. A wire example we can’t fly and need to step off at some point and even an earthed mat isn’t perfect as you would need reliably low impedance ground conditions. This is about as good as it gets at the moment without putting a barrier around your car every time you charged it up😃
1) Current regulations (18) require all circuits to be protected by RCD, which means you could just add a MCB as you have protect from stray currents. 2) Older installations can use a MCB + RCB combined 40A in the CU. 3) Although there are issues with TT earthing in dry conditions (or it getting broken), but in general it is much much easier for a charger to detect earth fault reliably than a PEN fault reliably.
Is this in response to, and does this put the lie to the comments from Matt:e on the UK EV Installers Facebook page regarding the BS standard for chargepoints where they claim you must have the O-PEN protection separate and therefore none of the chargepoints incorporating protection within comply with regulations?
Is there a list of the number of losses of PEN that have caused injury somewhere? OK (at 11m:30s) - so 50 'injuries' a year but how many of these were life threatening and how many related to the use of EVs? My concern is that the wiring regs are following the general 'nanny state' desire for protecting people *at any cost* and that, as usual, this is so hopelessly unsustainable that our society regulates our lives to the point they become simply not worth living. IMO, the health authorities' and government's reaction to C-19 is another example.
It is good to put the regulations in now before EV charging will be more common. The fact that EVs now have not yet caused so many accidents is not an argument.
@@okaro6595 OF COURSE it is an argument!! Do you not think there is a reason the design safety factor in the aviation industry is 1.5 and that of the automotive industry 3 times that? It *all* comes down to money in the end and doubling or trippling the cost of an EVSE for the sake of a 1 in a billion chance of a fatality occurring is as utterly moronic as it is non-ecological (ie a waste of resources).
How is this ADS?? , as in order for the Zappi to disconnect it needs to detect a current flowing though a person, I understand the Zappi monitors the voltage also and this current sensing is a worst case scenario, which by all accounts is better to have than not I am just unsure how regulators approve this approach of using a person receiving a shock in order to disconnect?
What protection is there when I charge my car via a 13A plug? Will these now be banned or will dedicated 13A socket outlets, protected by pen fault isolation, become mandatory? Perhaps we could market a rubber mat to park the car on? Bit like those put down in front of switchgear panels? I guess quadrupeds could be put more at risk with this type of earth fault. Dogs weeing on the wheels of the car with a pen fault would be in for a shock?
Domestic supply is rarely 3 phase to a single premises. It is still 3 phase from the substation, each premises just uses one of the phases for its supply.
I never had any complaints with the items needed to comply to. I simply don't get why the charging and running gear on the EV's isn't 1 - Double Insulated or 2 have a grounding strap dangling on the floor much like we've had for decades for the build up of static during movement. Either of which would help negate fault current going through a person. That said at some point if a manufacturer makes the car almost completely out of carbon fiber - the new Lotus/Rimac etc which effectively would be insulated. It does still come across as we're problem solving for things that never should have been an issue had the design of the vehicles evolved from a metal box with rubber feet.
Maybe it has something to do with the fact that cars get wet and rattled about a lot? Once these things have been ragged about off road for 20 years would you still trust it to be double insulated?
Wrong on so many counts. Carbon fibre laminate is highly electrically conductive! A dangly earthing device would have an impedance in the megohms so be useless. To make the cars class 2 insulated would be impractical and impossible in a on board charger fault condition. I could go on.
I'm only guessing here, but because the AC-DC charger is built into the car and the high voltage battery charges the 12v battery which one terminal is connected to the car metal work (negative terminal) I would assume the charger CPC is also connected to the car body to stop any potential floating voltages.
@@blobstrom makes sense I suppose, once you consider the cooling system is hooked up to the charger too. Some of the first EVs used an induction paddle to avoid a wire-to-wire connection.
Might be being an idiot but surely fitting a 30ma type A rcd before your car charger would resolve the single phase problem because touching the car at 70v it would cause an imbalance and trip in 0.4 s.?
Just come to murica with our single phase 120/240v system that’s always grounded no matter what with a primary and a secondary earth ....no electrical shocks here unless something seriously wrong
PEN-fault is the seriously wrong situation. US is in no way immune to it. Sure the lower voltage helps somewhat. Electrocution deaths in Maryland 2005-15 0.87/million, in England 2001-17 0.39/million.
Is this in response to, and does this put the lie to the comments from Matt:e on the UK EV Installers Facebook page regarding the BS standard for chargepoints where they claim you must have the O-PEN protection separate and therefore none of the chargepoints incorporating protection within comply with regulations?
@@efixx We couldn’t agree more. As registered installers of their products we believe they offer a really safe chargepoint which gives our customers peace of mind. We should note....we are also fans of Matt:e. Perhaps an offering on their devices would be a good video?
Love a good EV Charging video! 👏
One of my favourite videos of 2020 - always great to spend time with Dr Chris 🦾👍
Great work Gaz and Dr Chris
Great deep dive! Seeing how the different phases interact like this in the case of a broken PEN connection is fascinating. Hidden complexities in such systems
Something I think was worth a mention is that we are no doubt going to see manufacturers take the cheap way out and use an earth reference probe, if the soil arround that probe dries out or the probe is disconnected then the voltage fault on single phase wont be detected. The only method that can be trusted I believe is measuring for fault current on the CPC. 20ma is a good threshold for this as the output will only trip if current is shown on the CPC. I can see this voltage detection via a reference probe being a problem and even giving nuisance trips.
I’m an electrician, & just starting in the EV installations your videos are very informative.thank you
i disliked your comment
I have a large gravel drive where I could easily dig in an Earth mat of some kind. How big would I need to make it? Where can they be bought from?
If you simply have an earth rod in place connected to the MET of a TN system, does an EV charge point have a TT supply or does the TT have to be seperate of the MET?
Best explanation yet , bar putting impenetrable barriers around your vehicle every time you charge it up this is as safe as it gets at the moment . Even with the latent risk of injury or death still a very small risk .
Makes toasters and wet or damaged extension leads in the garden seem nuclear 😂
Great video. I guess we are lucky here in the US, as our chargers don't use neutral and only take the two split phase conductors and safety ground to the chargers. There is no neutral line to get lost! 😎 The newer chargers have GFCI protection built in.
We don't have split phase in the UK
@@steverobinson8170 Are 110v site TXs not split phase?
The charge is grounded and the ground wire is the PEN (Protective Earth Neutral) outside the main panel. As long as you have anything connected to the neutral it is a risk. The fact that US uses ground rods and the lower voltage helps somewhat.
A GFCI does nothing to protect against a PEN-fault.
@@okaro6595 Yes I know, however we have no neutral to deal with for the EVSE. Because we use traditional single phase and use split phase, we only bring out L1/L2 to the chargers (240VAC), then safety ground. So we can't have PEN fault with EVSE, at least level 2 EVSE, is what I am talking about. The only time we use neutral are for 120V circuits.
RCDs are the same style protection as a GFCI just we have them in the fuse board rather than dotted about everywhere
What a useful video. I get a free BP Pulse home charger with my new EV but I think i will take the alternative 2 year subscription instead and pay for a Zappi
When I get my drive done should I have an earth grid installed under it? Does it need to be stainless steel of at least galvanised?
I was watching this and trying to understand Indent 5. As I understand it, the Zappi was sitting on L1 and N, the PEN fault was introduced. Then, the Zappi was tripped when around 19ma of current flowed down to real-earth. Given there is a PEN fault present, that only way the Zappi could possibly detect that is to detect the current difference between L1 and N, so why is that anything special? that to me sounds like the exact description of a 20ma RCD? What am I missing?
@tim g I think what Chris is describing though is they are detecting current flowing through the CPC (earth) that is connected to the car, so while I understand an RCD in the fuse board would not trip, what the Zappie is doing, as well as the voltage check is simply the same as an RCD would do, but instead of looking for a fault current in-balance between L&N back to the board, its relying on the fact that the fault current would go through the CPC to the car, and through the person touching the car. In effect its still just an RCD but in a slightly different configuration and instead of measuring an in-balance between line and neutral its relying on sensing a current through the CPC that is going to the car its self. So if you are only looking for a 20mA fault current (as opposed to low impedance path to real earth that an earth rod would provide), it seems that you would get a far better installation of you had a reference earth rod, only needs to be low enough impedance to present a fault current. I would rather that than rely on 20mA + flowing through one of my children for 5 seconds before the fault current trips the protection
@tim g depends, many properties have old steel or even lead armoured cables where the sheath is the earth, which, makes contact with the ground it is buried in, and of course, in the event of an upstream PEN fault, this makes the real earth ground live. Sticking an earth rod near there would not be helpful. So yeah its not always simple to find a decent place to put an earth rod, I think the regs say something along the lines of 10 meters away from any services. In practice, in my house, both the gas and water come in to the property in plastic, although my electricity supply does come in on an old lead 3-phase 100A feed. For houses at least in the UK, services generally come in to the front of the house, so the back garden is generally a good place to site an earth rod. As you not always simple, but still very doable when you don't need a low impedance path, at 240v even a ground reference with a 5,000 ohm impedance to ground earth will give you a fault current in excess of 30mA - more than enough to trip. I understand why spraks don't like installing them, but there is no doubt thats better than creating a fault current through one of your children :)
@@gerrysweeney Earth rods can be unreliable and, especially if there is a PEN fault leading to large currents flowing through the earth from things like underground pipework bonded to CPCs and the rod is anywhere near those. There's a lot more to this than simply banging a rod into the ground. Whatever buried services are around can play a very big role in this, especially under fault conditions and it's often difficult to establish what might be there, especially on older buildings.
Install a foundation earthing under 1 Ohm, connect it to PME bar into your house, and you will never have problems from broken PEN conductor out on the street. Here in Greece foundation earthing is required in all new buildings from 2006
Fine, but that as the vast majority of buildings are not new, then you still need a solution for the vast majority built before that requirement.
A great insite from Gaz and Dr Chris.
For those wanting more information on how the faults could occur and effect all types of installation watch the same subject by John Ward
Is it better (safer) to have integrated PME Fault or an external device say with surge protection?
In the US, practically every charge point (EVSE) has a built-in RCD (GFCI), for the past 10+ years. Interesting that this is "new" technology in the UK, especially since RCDs have been used for a while. I can't imagine Dr. Horne would have been the first to think of putting one in a charge point. The regulators should just require every charge point to have an RCD built in like the US, and get rid of all those other silly regulations. It's also strange to think that UK houses have only just started to use supplemental ground rods to protect against neutral faults while in the US they've been required since 1978.
RCD wont help with PEN fault...
RCDs have been used in the UK for decades, and all new installations will have them, but it does not protect against a broken PEN in the street.
Hi, great video. Can I ask why PEN fault detection/protection is not added by the DNO before entering the meter? If there is a PEN fault, wouldn't we be just at risk from touching any bonded metal in the house too? Sorry if stupid questions, I'm a newbe.
I asked the same question (Gaz) 👍🏻
@@efixx I worked it out 😄. If they fitted PEN fault detection at the meter box the a PEN fault would take out whole streets. So, they reckon so few people would be at risk the put the onus on the individual. Just my hypothesis though!
That’s good. The PEN fault causes charger to stop so go indoors to make a cup of tea and when touch the tap or metal sink or radiator you get a shock! Would it be better to protect whole installation from PEN fault?
I was thinking that. What about the rest of the installation?
I believe that’s one of the reasons why things like metal water pipes, metal gas pipes and other extraneous conductive parts are connected ( bonded ) to your earthing point in your house, or should be.
SIMON HOWARTH yes bonding helps in certain circumstances. However in a supplier side PEN fault that this scenario covers, the bonding acts as an excellent conductor to make all of the connected metalwork in your house live, most probably including your brass outside tap! This video covers an approach to resolve that very dangerous (but unlikely eg approx 500 per year in country) fault scenario but just for ev charger not rest of the house. Incidentally, I am no expert and uncovered this as I was researching what I need to do with bonding in my house when I do some house refurbs, asit has changed since I was a sparks prior to 1990. I found some excellent videos including this one and also a variety of electrical instructional videos by John ward where I saw the pen fault explanation, google him or flame port, his website.
@@marke8732 That is the point of bonding. To equalize potentials so you will not get a shock between an appliance and the sink. Sure if you stood in wet floor bare footed that would cause a problem.
One would expect the risk factor relating single phase to be expressed as a ratio of reported faults to total installations. This would not artificially reduce the “risk factor” simply due to the number of installations.
Good video. Just one point if you could clarify. Chris explained that they have a built in RCD so no need to install one in the DB if not buried on plaster (i.e. wired in SWA clipped direct). How is that RCD reset? I didn’t see that it was a user operated device. Does the charging unit reset it internally, if so, how? Does it have a test button for 6 monthly operation? Also, you were tripping out on 19mA as opposed to the 30mA we would normally install, so surely wouldn’t hurt to still have an RCD at the board as the two would discriminate. Also, is 19mA a bit low for a trip, would it be considered a nuisance trip?
RCD's are mandated to trip in the range from 0.5 up to 1.0 times the *nominal* value of residual current.
If a RCD is marked with 30 mA I_delta_nominal, it must trip in the range from 15 to 30 mA.
Thus 19 mA is a valid target to manufacture for.
They demonstrate a reset by the user, in the video at 16:51 .
The product is made with sensing separate to contactors/relays (that "energises" the cable going to the EV/the 'type 2' connector), and the relays are controlled by the embedded microcontroller. So a reset is done via the electronic control panel
It does have some form of self-test.
It doesn't need a test button as it can do an RCD test every time the car is connected by injecting a current into the sense transformer ( with a seperate winding) before turning the output on.
Good reply folks, thanks to everyone for the info. Clever little machine then the zappi. Might start using these instead of Sepam’s 😉
It was also measuring the earth current rather than the line and neutral current imbalance, which would be equal if there was a PEN fault. Watching the e5 group opened my eyes to earthing etc.. You could even have a scenario where 3 houses fed by different phases are off one cable, losing the PEN near the origin would mean all the neutral currents in all 3 houses could flow through anything that is connected to the mass of earth, a metal water pipe etc. or a person touching a charging car
Please correct me if I've misunderstood here, it detects a broken PEN Earth gone and still continues charging the EV/car with the car body above 70 volts, crazy, should trip and stay tripped once it detected PEN fault. Surely hi-tec can come up with something smarter than this.
The Zappi product mentioned in the video uses a different method similar to an RCD.
Do you have information on the percentage of imbalance you are introducing and the phase currents you are simulating?
My EV keeps getting nuisance trips, its the easee one charger, I live in a new build. Is there any chargers you would recommend to prevent this?
Brilliant!! 🙌
Great video still not sure about EV chargers
I think it should be a specialist job for people who have been trained purely for installing EV chargers? Great video Gary, thank you
The video seems to be saying that this setup is fool-proof and can be installed by a builder who's done the full 3-day NICEIC qualified electrician course.
Honestly most of the guys who just install EV chargers are total cowboys, would rather my local spark could do it.
3 day qualified electrician 🤣
Silly question but , in a tncs system if we lose the pen conductor how we manage to still have power? How the circuit is closed if neutral and earth is cut?
The current which normally flows down the PEN can take various routes depending on where the break is. e.g. via other houses on different phases, down earthed service pipes (gas or water) and other equipotential bonding or supplementary earth electrodes. See John Ward's video "TN-C-S Danger - Broken PEN Conductor (Combined Earth & Neutral)".
Hi Gaz, posted this on a few videos and never got a response, do I have to finish my install completely to pass the install or does it just get marked on quality of work in regards to the AM2? Thanks mate
Hi there, Im getting my first EV, a model 3 Tesla, and have purchased a Tesla Gen3 Wall connector. Do I need to fit PEN fault detection between the wall connector and the distribution board?
Yes - Tesla do not include it in the design
@@efixx can you recommend a suitable product?
Is not just a risk of electrical shock but all electrical equipment will suffer from over voltage so it will become faulty. It happened to me when neutral accidentally disconnected in CCU. I have 3 phase in 4 stories building split in 5 flats and in couple of flats all electronic devices was burned. So i installed in between metter and ccu o-pen monitor. Because I have 3phase I able to make my power network super safe compare to single phase.
I love you man but when you’re talking to the viewers, look at the camera. When you’re talking to a co-host, look at them!!! Forget the camera!!
How are we going to install our 13A socket EV chargers now???
If you like life in the slow lane then 13A is the answer - 50hrs plus to charge a 100kW 🔋 battery
Which brands have similar protection built into their EV charger except Zappi?
So what about if I happen to be digging up my drive anyway & want to go the great big earth mat route?
I am finding it very difficult to find guidance/help on doing this, even by trying to involve companies that you might expect to know. I am interested from the perspective of going off grid in a power cut as well as the EV side. How big does the mat need to be for example? Would a condudisk or multiple condudisks serve instead? Does the mat need to go all round the house as the next proposed set of wiring regs confusingly seems to suggest?
An 'Earth Mat' is just a term.
You can create a Virtual Earth Mat by sinking Earth Rods and using the Ground they're sunk in to create the Virtual Mat.
Basically the Ground connects them all together.
You might get away with just one Earth Rod on a 'Domestic' type installation, it all depends on how well your Ground conducts electricity.
Keeping things simple here, You would sink test earths rods around your property and measure the resistance to your main Earth Rod.
A bit of Ohms law and Hey Presto you have your Earth Mat.
Imagine your property built on a Salty Marsh compared to one built on dry gravel and rock, which one would have the lower soil resistivity ?
You could also dig a trench and lay a long galvanised pipe in it etc. Loads of ways to create your Earth Mat.
Regardless of what the regs say, if you want to make it safer, install a ground rod, and connect it to the CPC inside the Zappie at the car side, that way, should there be a pen fault event, your earth rod would provide the path to real earth for the fault current that would trip the Zappie, and that would save one of your family having to touch the car to create the path to earth... Thats what I think anyway...
I'm not sure from this video whether it takes someone touching the vehicle after the earth PEN has failed to cause the Zappi to trip or does the Zappi immediately trip once the earth PEN fault has been detected without someone touching the vehicle?? if it takes someone to touch the vehicle in order for the Zappi to trip then the vehichle body could be sitting there potentially live??
If there's no one there to touch it, what's the issue?
That seems like a clever bit of kit. I can imagine the headache of going out to nuisance trip, and trying to ascertain the cause of said trip! When the 18th edition first came out (before the amendment) I’m sure it said something about electrical separation being a solution in this scenario. Has this now been removed in the amendment? Even though you’d need a pretty big isolating transformer, I thought this was a really good solution to this type of problem?
Great work Gaz👍
Not really practical for residential of commercial installations (cost/efficiency/space)
Nice to see the cleaver people from my energy. I’d be annoyed if I woke up to find my car still had a low battery. Could it not try and reset after 2 hours and see if the fault had gone? (Ie false trip)
Great video, really interesting.
great vid do love a zappi
It's not clear why this is a particularly innovative solution. It seems to be a simple voltage comparator and RCD. It looks like it covers all bases, but why was it causing headaches in the industry?
It's just that it wasn't previously required. So it's just a complaint about doing something new or in addition to existing implementation requirements.
@@thomasbonse I don't understand your reply. Can you re-word it?
I'm also thinking the detection of CPC absence might be the clever bit. RCDs are usually blind to PEN faults because the shock current has flowed through both the line and neutral of the RCD sense coil i.e. no imbalance is detected. I wonder how they've solved that.
There's a nice illustration here ua-cam.com/video/JRHyqouJPzE/v-deo.html&ab_channel=JohnWard
Regular RCD's are sensing current in live conductors (meaning lines/phases and neutral conductors), and that is fine for faults where live parts make contact with earth/PE/CPC-connected metalwork.
When a PEN breaks, the dangerous current can flow from the PEN (on the side of the break that is detached from an earth electrode) to the PE/CPC to exposed metal and through a person to earth ground to return to the supply transformers earth electrode. As this does not create an imbalance in the currents on live wires for a regular RCD to detect, PEN faults need a separate current sensor for currents in the PE/CPC conductor to detect these fault currents.
In short one RCD on all but the PE/CPC combined with current sensing of the PE/CPC alone combined with voltage sensing.
I don't know why ready-made (all in one with regular RCD protection) PEN-fault detectors were not generally available before. Too few requests?
The headache may have come from the lack of explicit permission to rely on detection of fault current in the PE/CPC (when voltage between line and neutral is within range), and the lack of availability of suitable components for PEN-fault detection and full disconnection of all wires.
before we had RCDs didn't we have kit that detected leakages on the earth conductor, seems the same idea, detect that then open all the circuits (including the PEN)
@PETER WILSON Yes, they measure the current in the CPC as well as teh normal imbalance method
Eugh, TN-C-S causes sooo many problems. Sheer laziness by the DNO's :(
Whack in a rod. (difficult in some modern estates to avoid the existing utility lines though :( )
Foundation earthing which may come in with the next BS7671 amendment may be the answer.
Hi Gaz, i am in the understanding that the EV charger in the EV is double isolated and has no connection to the EV chassis at all.
All standard car charges have a pin to ground/earth that is connected to the chassis, even if the charger inside the car isn't using it. Look at the pin-outs on a CCS or Tesla connector.
Great Video! Although it seems that a man, woman or child needs to receive a shock of up to 19ma to trip the unit if the voltages are within the 12% range under fault conditions. Is that super safe? If so surely a demonstration could be illustrated without the box of tricks with variable impedences?
But there is no way currently available to trigger a trip without someone or something directing current to true ground creating the imbalance, some people can be adversely affected at these low currents even fatally ,a practice test could still be dangerous .
If the imbalance is set much lower the risk of nuisance tripping will be more likely.
It’s the old bird on. A wire example we can’t fly and need to step off at some point and even an earthed mat isn’t perfect as you would need reliably low impedance ground conditions.
This is about as good as it gets at the moment without putting a barrier around your car every time you charged it up😃
1) Current regulations (18) require all circuits to be protected by RCD, which means you could just add a MCB as you have protect from stray currents.
2) Older installations can use a MCB + RCB combined 40A in the CU.
3) Although there are issues with TT earthing in dry conditions (or it getting broken), but in general it is much much easier for a charger to detect earth fault reliably than a PEN fault reliably.
Great video & he really knows his stuff.! Just a shame the Zappi is so ugly 😔 think the Andersen would be my go to, as contractor and end user..!! 🤔
Is this in response to, and does this put the lie to the comments from Matt:e on the UK EV Installers Facebook page regarding the BS standard for chargepoints where they claim you must have the O-PEN protection separate and therefore none of the chargepoints incorporating protection within comply with regulations?
Is there a list of the number of losses of PEN that have caused injury somewhere? OK (at 11m:30s) - so 50 'injuries' a year but how many of these were life threatening and how many related to the use of EVs? My concern is that the wiring regs are following the general 'nanny state' desire for protecting people *at any cost* and that, as usual, this is so hopelessly unsustainable that our society regulates our lives to the point they become simply not worth living. IMO, the health authorities' and government's reaction to C-19 is another example.
It is good to put the regulations in now before EV charging will be more common. The fact that EVs now have not yet caused so many accidents is not an argument.
@@okaro6595 OF COURSE it is an argument!! Do you not think there is a reason the design safety factor in the aviation industry is 1.5 and that of the automotive industry 3 times that? It *all* comes down to money in the end and doubling or trippling the cost of an EVSE for the sake of a 1 in a billion chance of a fatality occurring is as utterly moronic as it is non-ecological (ie a waste of resources).
How is this ADS?? , as in order for the Zappi to disconnect it needs to detect a current flowing though a person,
I understand the Zappi monitors the voltage also and this current sensing is a worst case scenario, which by all accounts is better to have than not
I am just unsure how regulators approve this approach of using a person receiving a shock in order to disconnect?
So basically fit a zappi if you want a fully safe ev charger.
You might have other manufacturers taking issue with you if you're telling everyone that their chargers aren't safe.
They are easier to install and still meet the requirements as I understand it
What protection is there when I charge my car via a 13A plug? Will these now be banned or will dedicated 13A socket outlets, protected by pen fault isolation, become mandatory? Perhaps we could market a rubber mat to park the car on? Bit like those put down in front of switchgear panels? I guess quadrupeds could be put more at risk with this type of earth fault. Dogs weeing on the wheels of the car with a pen fault would be in for a shock?
When my ink runs dry, it's then I know that I have a pen ✒️ fault 🙄
gold star from mrs goldings 20:44
All - you do you know domestic supply is not 3 phase?
Domestic supply is rarely 3 phase to a single premises. It is still 3 phase from the substation, each premises just uses one of the phases for its supply.
remarkable
👍👍👍👍👍
clever folk on screen
I never had any complaints with the items needed to comply to. I simply don't get why the charging and running gear on the EV's isn't 1 - Double Insulated or 2 have a grounding strap dangling on the floor much like we've had for decades for the build up of static during movement. Either of which would help negate fault current going through a person. That said at some point if a manufacturer makes the car almost completely out of carbon fiber - the new Lotus/Rimac etc which effectively would be insulated. It does still come across as we're problem solving for things that never should have been an issue had the design of the vehicles evolved from a metal box with rubber feet.
Maybe it has something to do with the fact that cars get wet and rattled about a lot? Once these things have been ragged about off road for 20 years would you still trust it to be double insulated?
Wrong on so many counts. Carbon fibre laminate is highly electrically conductive! A dangly earthing device would have an impedance in the megohms so be useless. To make the cars class 2 insulated would be impractical and impossible in a on board charger fault condition. I could go on.
What would the grounding strap help?
Why are EVs class I appliances?!
@PETER WILSON they're talking about the car, not the charger
I'm only guessing here, but because the AC-DC charger is built into the car and the high voltage battery charges the 12v battery which one terminal is connected to the car metal work (negative terminal) I would assume the charger CPC is also connected to the car body to stop any potential floating voltages.
@@blobstrom makes sense I suppose, once you consider the cooling system is hooked up to the charger too. Some of the first EVs used an induction paddle to avoid a wire-to-wire connection.
Might be being an idiot but surely fitting a 30ma type A rcd before your car charger would resolve the single phase problem because touching the car at 70v it would cause an imbalance and trip in 0.4 s.?
The PEN fault occurs outside of installation so an RCD detect the difference. This video might help explain - ua-cam.com/video/ZedTmlTLH2w/v-deo.html
A lot of ifs in this 😮
Just come to murica with our single phase 120/240v system that’s always grounded no matter what with a primary and a secondary earth ....no electrical shocks here unless something seriously wrong
We need protection against the "Seriously Wrong!"
PEN-fault is the seriously wrong situation. US is in no way immune to it. Sure the lower voltage helps somewhat. Electrocution deaths in Maryland 2005-15 0.87/million, in England 2001-17 0.39/million.
@@okaro6595 why are you comparing one state in the US to the entire England ? Makes no sense.
@@okaro6595 where is your 7yr old data for one state from?
Nerds lol only joking great stuff
Sorry, you lost me at 0:52 “volts then crack on”. Ditch the Harry Potty accent, doctor.
Is this in response to, and does this put the lie to the comments from Matt:e on the UK EV Installers Facebook page regarding the BS standard for chargepoints where they claim you must have the O-PEN protection separate and therefore none of the chargepoints incorporating protection within comply with regulations?
Myenergi believe their approach delivers the highest level of safety in all supply arrangements.
@@efixx We couldn’t agree more. As registered installers of their products we believe they offer a really safe chargepoint which gives our customers peace of mind. We should note....we are also fans of Matt:e. Perhaps an offering on their devices would be a good video?