BS7671 Section 722 Electric Vehicle Charging Earthing Arrangements
HTML-код
- Опубликовано: 4 июн 2024
- A look at BS7671 Section 722 which covers electric vehicle charging installations.
Support this channel at Patreon: / jwflame
Twitter: / jwflame
Facebook: / jwflame
Instagram: / jwflame
Website: xo4.uk/?EVc
Contact info, sending stuff in etc.: xo4.uk/?YTT 
Наука
These manuals are a great remedy for insomnia.
😂😂😂
Enjoyed the way you broke it down and explained it all.👍
Amazing! Thanks John. Your videos are superb.
TN-S is a grey area, as it may not be connected all the way back to the transformer as any repairs to faults in the cable where a section is replaced will be PME. Also if the incomer is replaced that will become PME and that will immediately make the installation non compliant. Realistically ALL installations will require their own earth rod.
Totally agree....why don't the regs just say must have a TT system.....
Yep, the regs state that if the supplier can't guarantee that the TN-S system won't become a TN-C-S at some point, then the installation should be treated as a PME for the purposes of the EV charge point.
@@stuartbirch7815 Yes and of course the DNO can't guarantee this - so basically unless it's a TT system, you have to TT the charger... or use one of the new fangled gadgets that disconnects the earth and supply in case of a fault...
@@NickRavenscroft We're all waiting for those gadgets to arrive!
Thanks jw very interesting as I'm about to embark on a ev changing installation course so I can install them full time
Very clear and concise video. K
Well done John
Thanks for making these regulations so interesting....keep up the good work
Excellent information!! Thanks for that👍
This video is timely, as I'm presently looking into doing this in Canada. Regulations here here seem much less complex. I believe we are allowed to use the building ground on our conventional TNC-S system for a single vehicle home charging system. Freestanding multi-vehicle charging stations are very different.
Also, really clear and useful video. Of course time moves on and as for para 3, of the guidance, some ‘unicorn ‘ devices are now available since the vide was made.
Install an earth rod. All fine and dandy if you have access to some “garden” that can be dug up. Not so easy in cramped housing areas where nearly all of the ground is now either asphalt or concrete so that the car can be parked on what was the front garden...
Hire a rotary hammer and drill through the asphalt or concrete. It's not an impenetrable problem. If you have offroad parking of any sort that's better than a lot of people.
Here in Malta we employ a TT system countrywide and all ground is either limestone, concrete, or rock. All earth electrodes are drilled with a rotary hammer with the minimum depth being 2.2metres. Then bentonite clay is used to create an effective contact between the copper rod and the ground.
Very useful, thank you for this.
Delighted to say theres a product which complys with iii) MyEnergi Zappi 2.0 - appears to be the first of its kind.
Liam Wolstenholme
They are not compliant with the regs, where in the regs is this device listed? If it was compliant the device they use would have a bs en number. They don’t have compliant equipments. May sure if you install them the manufacture takes full responsibility for any eventuality after install. Get it in writing.
Great video. Just curious are you going to continue your series on metal conduit at some point in the future?
Thanks for breaking down the regulations into an understandable format.
Big issue here is Earth rods in built up area’s, with all the other services underground, it’ll be like Russian roulette.
John, Thanks for this great video....The best out there as usual!! A question if I may:
If I have got a TN-C-S. ; I install an MCB in the house with SWA running to an out building to another consumer unit to operate the EV unit which has its own type A RCD. Do I need a type A rcd in the remote cu as well as the RCD in the EV? ( the armour is separated to isolate the origin earth!)
No, an RCD is only needed for the EV unit.
if the outbuilding consumer unit supplies other circuits such as lights or sockets then an RCD will usually be required for those.
If it's only for the EV unit then you don't need the consumer unit at all - just take the cable directly into the EV unit.
With some of the new charge controllers you don’t need an earth rod. I specifically mention the Bender CC613 charge controller as it monitors for PEN failure and explicitly notes that an earth rod is not required as a result. I’m not sure about other charge controllers but I’m sure there are some that do the same thing.
Small issue, the charger is charging lithium-ion battery packs and therefore will not be drawing a constant current for the whole charge cycle.
Lithium-ion cells are finicky things more finicky than other battery types, so while with most rechargeable batteries one can get away with just applying a constant current and voltage source (though far from ideal) this will cause things to go very bad very quickly with lithium-ion cells. With lithium-ion cells the charge circuity will start constant current and then switch to constant voltage on each cell, meaning the charge current drops almost linearly with the charge cycle. At 50% charge, one is going to be charging at 50% current...
The regulations still have to account for, that 2 hours in to an 8 hour cycle, one is still going to be drawing ~75% of the current, so still not anywhere near as short term as an electric shower, but thinking of it as a full current all the time device is wrong.
Don't want to overcharge Lithium-ion cells either, so at 100%, we want to be sure to have 0 charge current.
Brilliant John exactly what I asked you for,you make it so clear
Very interesting, I would be very interested in a short video, should you ever feel so inclined on how the regs effect people with TNCS supplies and have there caravan connected in the driveways. Most people will not know what the regs say or what type of earthing they may have.
Hello John can you put RCBO instead of 32 amp mcb if in system is protected by 30 milliamp rcd please
Thank you for explaining the specs as within a certain amount of time all houses will have EV charging points, it will be the must thing to have to increase the value of the house for resale.
If two house of similar specs come on the ,market the difference would be the 400 quid box on then wall, it will go quicker. It is not only the 400 quid box but the installation fees.
Hi John, Have you seen the proposed amendments to this section yet?.
On a TN-C-S adding a separate earthrod to earth the charger and not using the provide earth. In this situation the nuetral is linked to the earth anyway in the TN -C-S does this not complicate issues further?
One thing is not entirely clear. When you discussed the impedence of the earth electrode and its associated cable, did you mean the loop value via the electrode, or the actual earth electrode resistance? To test the latter could prove very difficult unless the electrode was buried in an area which would allow earth electrode resistance test to be carried out - as one needs to insert the tester’s electrodes within the specified distance from the electrode under test.
This is something that I have fallen foul of today I'm on a tn-c-s system and I've had to install 3 earth electrodes in order to get it to pass the test. The electrian was doing an eicr test and commissioning the electrical installation in my garage which is now all on a tt system to comply with these regulations
Hi John I've done and completed my 17th addition qualification and would like to continue. I'm not under NICEIC or equivalent and would like to be so I can trade in the UK so I need my 18th addition.
Do I need to redo my level 3 or is their another way like a small exam I can take to update my qualifications
It depends on which amendment of the 17th edition * you're qualified to. The latest amendment only requires a refresher course.
if your using armoured cable on a tns from the board to the ev point are you not effectively creating a path through the armour and glands back to the origin defeating the object of having an earth electrode for separation. wouldnt you need to go into a plastic enclosure first. I understand your ok on tns but as you say its better on its own earthing arrangement.
Well timed JW.... Big thread over on a prominent EV forum where people are discussing whether they have an earth rod on their installation. Probably 50% do not
@J Foard Indeed, and there is no requirement to update an existing installation.
@J Foard I know, but if it's technically unsafe now, it should be fixed IMHO. I know that's not how the regs work, but still
Hello, most informative and timely. I was at a technical meeting last night listening to the requirements for EVs. I was told only a TT supply can be used at the source and only a time delay RCD may be used. Is what I have been told correct? Thanks in advance. Paul
If the supply is TT, the cabling to the EV unit will require an RCD, and that would need to be a time delay type to ensure selectivity (discrimination) with the RCD in the EV unit.
If the supply is TN-S or TN-C-S then the cabling may need an RCD depending on how it is installed, although in those cases it would be simpler to not have an RCD on the supply, just have the RCD in the EV unit.
This sounds like they are telling you irrespective of what the property’s earthing arrangement is the ev Circuit has to be a TT arrangement. And with this video it shows it doesn’t have to be
@@jwflame thanks for the reply. We were told if its PME at the moment at source it would have to be changed to TT and if this is on street from a street lighting column the others columns within 2mts of the charge point have to be changed to TT and on the same phase as the feed column. This can get very involved and costly by the sound of it.
@@1bigsyd hi, I thought so too but it appearance to be the case. Worrying as there were a number of people listening to what I can make out may not be correct.
@@1bigsyd I think JW pretty much said the opposite of that, unless I'm misunderstanding you or him. He makes it clear that using a *separate* earth rod is a good idea even if you have a TN-S installation.
Interesting and comprehensive as always JW. Just a question from a curious outsider: If a property has an existing TT earth, does a separate one always need to be installed for the EV charger regardless, or is it allowed to use the existing TT earth if the impedance value of the existing one is adequate?
You can use the existing earth if the impedance is low enough.
Thank you!
@@jwflame How low, anything below the recommended 200?
Hi John, great video. Would a PNB installation comply with 722.411.4.1 (ii) or a private transformer? Obviously this would not be the case with domestic installation but large commercial and industrial installation tend to be PNB. Your response would be greatly appreciate. Thanks Gary.
A PNB installation is not PME, therefore 722.411.4.1 does not apply to it.
At 9:00 the device that has this protection that doesnt need an earth rod is a Zappi
It is sort of nice that they have written in a provision for the use of a protective device that does not seem to have been invented yet.
Given the number of TN-C-S installations out there, somebody is bound to come up with a solution that can be integrated into a simple all-in-one unit which then just needs connecting to the supply and its own earth electrode. If they don't cut too many corners with the design, it will soon become a best seller.
Of course, there's still a bit of catch-22 situation going down where nobody wants to buy an electric vehicle if they don't have a charging point to plug it into, and nobody is installing charging points because nobody has an electric vehicle to plug into one .....
Where do you think the all in one unit is going to get its earth from ?. It wont be able to use the CU's /DNO's earth - so will still need an earth rod somewhere.
Is there an explanation as to why supplier-provided earthing is not acceptable for external car charging outlets on TN-C-S installations? I'm just interested as to the technical reasoning behind this. It's not as if there aren't other sorts of external circuits, albeit not with the same sort or power demand.
On TN-C-S if the supplier cable is damaged so that the combined E&N conductor is disconnected, all of the exposed metal parts of the installation connected to the earth terminal become live, and for most car chargers this would include the car becoming live, and a serious hazard. RCDs do not trip in that situation so the danger continues until the supply is switched off.
It's also why TN-C-S is not permitted for caravan sites.
Explained in more detail here: ruclips.net/video/JRHyqouJPzE/видео.html
OK, thanks. It sounds like it would affect metalwork, like the plumbing within a house as well due to the bonding, but presumably it's deemed that an occupant of a building ought not to be exposed to an independent earth than if they were outside.
@@jwflame Why would an RCD not trip in that situation? Surely there would still be an imbalance if someone touched the car and the current goes directly to earth rather than via the normal neutral return path?
@@davepuseyBecause... the same amount of electrical current is going from the Live supply > through the RCD Live terminal > through the appliance (car charger) > back through the RCD Negative terminal (fully balancing the RCD = no trip) > across the PE-N solid link in the cutout > not back to the supplier because the supplier PEN cable is faulty > through the CPC (earth) cable > through the charger to the car body and into anyone who touches the car body - possibly whilst standing on the earth with wet feet. eek!
@@speedmytube In that case then the solution is to simply not earth the car via the charger cable. Also, don't forget that by the time the electricity has made it to the car it will be low voltage DC anyway.
Hi John......check some of the Pod point install vids on RUclips.......some are actually recommending using PME...
...unbelievable
Yep, and if you talk to any of the EDS guys, the loss of Neutral on a PME is fairly common.
The newer pod-points do include a system that in the event of a PME fault do isolate the vehicle from the supply (they become double insulated class 2 devices) these units wont work if you cross wire the supply into the charge point or if the earth neutral is bad (earth disconnected or excessive volts drop in cable). they will also report supply faults (if wifi connected) that could potential be future hazards. Fitting an earth rod sometimes will make the equipotential zone just as dangerous where other fittings close by are connected to other earth systems! The other choices are dont fit a charge point, the end user then uses a mode 2 charger (connected to the PME) and is at the same or higher risk or Install an expensive and inefficient isolation transformer.
Hi John, just to pick up on Steve's question and your clarifying reply below (EV protective conductors). Can you consider including the reasoning for the regs in some of the videos? Probably obvious to skilled practitioners, but I'm not one! Otherwise it could start sounding like rules for the sake of rules, which I do know enough to know is not the case. I like the presentation, straight and to the point. I just think some of the content could be improved with a small tweak. Should widen the subscriber base. Cheers, BobUK.
I would guess that those who write the regs were considering an end user who has parked their EV outside in charge. It's raining, the end user is standing on wet concrete or, even worse, wet earth so they are nicely earthed. They put their hand on the exposed metalwork of the vehicle and get a belt (or worse) because there is a fault somewhere . Hence the need for an RCD that responds adequately to DC fault currents as well as AC ones. If anyone knows better, please feel free to correct me.
Many older UK houses like mine only have a 60A supply and already have two ring final circuits each fused at 30A. Does this mean that they simply cannot install a vehicle charger unless they pay to be upgraded to a 100A supply?
No, Apply some realistic diversity. 2 x 32amp rings, does that mean they are both running at full capacity all the time? I doubt they even have 15amps in constant use throughout the day. Add to that, that you will probably charge the vehicle at night, then the rings will almost have no load, when the car charger will be on. I would bet you'll be fine.
@@Nathan61705 - You're right of course, in practical terms the current draw shouldn't ever get anywhere near 60A but isn't there some limit in the regulations to how much potential load you can put on a given supply?
regulations aside, installers will check with the DNO, who usually will not allow a 32A EVSE to be installed unless they upgrade the main fuse-assuming the incoming supply is up to the job, of course
Western power do an 80A upgrade for free here in Midlands, uk
@@waynecartwright7276 I _believe_ all DNOs will do it for free, if the upsteam LV network can handle it. Sometimes they'll authorise a sparky to do it for them, sometimes they need to survey the local LV network (because their records aren't up to date).
Am i being a bit slow and missing the point? if the system is already TT and rcd protected with 30ma then why install an earth rod when it already has one. Also why can't the new charging point have
combined TNC-S and TT. Whats the problem if its not seperated. If the neutral drops out of the PME its still going to operate the RCD on the TT side.
If it's already a TT installation, then you don't need a second earth rod.
The EV point will still require it's own RCD, as the type required is not the usual one fitted to normal circuits.
You can't have a combined TN-C-S and TT - it's either one or the other. If you connect an electrode to the TN-C-S earth, it's still TN-C-S, just one with an additional earth electrode.
If the combined earth and neutral conductor on TN-C-S is broken, the RCD will not trip, and any conductive parts connected to the earth terminal will have dangerous voltages on them. This video explains: ruclips.net/video/JRHyqouJPzE/видео.html
@@jwflame Hi John
Thanks for your reply. I was testing a school that's got a swimming pool and the supply is a TNC-S I wasn't sure if that was a code 1 or code 2 ? I know that PME is forbidden for pool installations. So i phoned the electrical consultant that looks after school and the NICEIC helpline. Both came back with same instructions. All circuits feeding the pool must have RCBO 30ma protection and the pool distribution board must have a earth rod and be maintained at 20 ohms or less. We got round that because the lightning protection ends up connected to the main electrical system and is always lower than 20 ohms. So its TNC-S and combined TT. Point being that in the event of a Neutral drop out the RCBOs with trip. So are you saying that the RCDs will not trip. ? Nick
Hi Jon a concern we have is that if you put a Rod in the ground to have a separate earth for the car charger and your charging your car on your drive, there is a chance (be it very small) that under fault conditions on the TNC-S System you could potentially have a live external light and be able to touch the car which is earthed and receive a dangerous shock. We are being told that putting a rod in can also be dangerous and there is also possibility that 2 drives for 2 properties are side by side. Both properties could have cars on charge next to each other at the same time and the earth values could be very different between the houses and you could touch both cars at the same time. Doesn’t this also present a problem?
The dangerous shock from a light or other exposed conductive part would still exist even without the car - the voltage is between the light and the actual ground, the presence of an earth rod in the ground or an earthed object such as the car doesn't change that.
Two separate earth rods from different installations would be at the same potential under normal conditions, both rods being in the ground. A fault on one installation would cause a voltage on one of the rods and anything connected to it (such as the car), but that would be for a very short duration as the RCD would disconnect the supply - that's the main reason for making the installation TT rather than connecting it to the TN-C-S earth.
John Ward thanks John. Appreciate the reply and will pass your thoughts on. Cheers
Refer to the IET Code of Practice for charging EVs which includes a risk assessment form for this situation. You must not have equipment on two different earthing systems (e.g. PME and TT) within touching distance of each other. If you do, you either need to remove one of the items, or convert the earthing arrangements so they are both the same. Two cars each with TT earthing isn't a problem, if one is on PME and the other on TT it is. Your neighbour's car does count if you can touch it from your property (so a tall fence is a solution).
I have a Class 1 electric garage door with a metal frame (PME, as part of the house), a metal outside tap (could be swapped for plastic), four Class 1 luminaires including one next to a proposed EV charging point (don't want to swap them, currently TT), plus a BS 1363 socket I want to use for charging an EV (needs a Type A RCD, on PME as next to the garage door), plus a proposed Type 2 EV charging point outdoors. I could touch most pairs of these Class 1 items or EV(s) simultaneously depending on where the EV(s) get parked (cars can move about, unlike most large electrical appliances). Something has to give.
I could build a 2.4 Ohm earth (see Annex G of the CoP, at least 16 rods in 8 earth pits) and use PME everywhere held down by that earth, or I could convert the whole house to TT (which would mean installing a discriminated RCD for the whole house plus a single rod right over the electric, water and gas mains), or I could install by the end of the year in which case three x 4 foot earth rods near the EV would suffice (17th Edition Code of Practice is quite different to 18th Edition), or install an isolation transformer (75kg and £750 plus a single earth rod to TT the secondary winding). If I do build a Big Earth and the DNO's neutral does break, my lawn would become the main neutral path for all properties further away from the sub-station than mine, and the guidance on how to size an earth conductor for that just doesn't exist (but I don't think it would be recorded on my electricity meter, so that's something). The cable in the street is 185 sq mm, and Screwfix definitely don't stock cable that size! But it's three phase so if it's balanced, the neutral current is zero, so 16 sq mm is as good a guess as any, with a smoke detector above the earth cable route just in case the DNO loses a phase or two at the same time as the neutral. If it gets really high the DNO's supply cable to my house (25 sq mm) would melt about the same time as my earth wire I suppose.
I could also wait for the mythical device to be specified (722.411.4.1.(iii)) and available, and fit a single rod for it. This has to be the way forward, but when? And as a UK-specific device, at what price?
What I am not sure of is whether RCDs upstream of the EV also need to be Type A (ordinary Type AC RCDs are "blinded" by residual dc, and all RCDs in series will carry that dc so I think the answer is yes, or perhaps the answer is "good question, wait for Amendment 1 in 2021 and we'll spring it on you then", or perhaps a 100mA RCD will shrug off a few mA of dc that a 30mA RCD can't). I don't know if I could buy a Type A/Type S 100A 100mA 2 pole RCD if I wanted (or needed) to. And as for Type B RCDs, they seem to start at about £500 and are 4 modules wide so I'm not going there. All that dc also turns up in the DNO's transformer but I have enough to worry about so it's up to them to keep it cool.
In the first instance I shall buy another tank of diesel.....then wait for heavy rain and hope my Ze comes down a bit.
Thanks for your detailed response and it has confirmed my suspicions of fitting a rod straight under an EV charging point outside a house that is supplied by a TN-C-S supply where class 1 external lights and taps are likely to be present. It’s also very likely that someone might want to clean the inside of their car whilst it’s on charge and could potentially introduce mains power and earthing into the car via a hoover.
We are on projects of new build houses where the development constraints are that all plots are to have a charging point facility or ev ready charging circuit to all plots for future adaption. As these circuits we install are to be used for a car charger, we need to ensure that all earthing etc is in place ready for installing the actual charger itself. As per your video and the scope of this section in the regs, these requirements apply to all circuits that are intended to supply electric vehicles for charging purposes. So although we aren’t actually fitting a charger, (in some cases we are just fitting a rotary isolator in its place) we have to ensure that we meet this criteria.
I’m having another discussion with the contractors later in the month to discuss how we will move forward come January with all the above in mind. For my reference to the contractors could you please advise where it states that you cannot have equipment on two different earthing systems that are in touching distance of each other!? That would help me out.
Also a further thought on this, and not sure how possible/feasible this potential solution is, what if the DNO provided TN-S systems to all the properties rather than TN-C-S? Would that alleviate all the issues? Most domestic sites now, well the larger ones anyway have a local on-site substation so not sure if they could pull TN-S supplies from these?
Thanks again for your thoughts.
@@danielbell9192 722.411.4.1 is specifically about TN-C-S (it calls it TN but then says PME). I don't know how TN-S should be treated, perhaps the risk is lower?
The Code of Practice for Charging Electric Vehicles 3rd Edition is clear about simultaneous contact with items connected to different earthing systems. Annex B gives you risk assessment forms for this very problem. I think (but it doesn't include a reference) the regulation in question is 411.3.1.1 "....Simultaneously accessible exposed-conductive-parts shall be connected to the same earthing system individually, in groups, or collectively....".
Unless your hoover is very old indeed, it will be Class 2 and therefore safe to use within touching distance of an EV, and note that 722.55.101.0.201.2 says "...Portable socket-outlets shall not be used...." so no extension leads allowed near, or to supply, an EV (but yes, both happen).
So the video is spot on: use TT for an EV being charged outside because nothing else is practical or available. But you do still have to comply with 411.3.1.1 so no PME-earthed items within touching distance. If there is no touching possible, a single earth rod may suffice (perhaps two if your soil has high resistivity, you need to measure the resistance of your rod(s) either way). If touching is possible, then either TT the whole house provided that adjacent properties are not within touching distance, or PME your EVSE (which will need multiple earth rods for the EVSE, widely spaced, which is unlikely to be practical or affordable), or fit an isolating transformer (again, provided that adjacent properties are not within touching distance because the EV body may come into accidental contact with true earth, and limited to one EV only). All as per the video.
But 722.411.4.1.(iii) comes to the rescue if and when you can buy and fit an electronic under-voltage device in the EVSE or in its final circuit. Then you can use PME because the electronic device will disconnect all three wires in the event of a broken neutral. But you can't do that yet because there isn't a published specification to meet (though some EVSE manufacturers do include under-voltage relays that meet their idea of what a specification should be).
Just make sure you don't drive your earth rod through the gas main (different regulations but a whole heap of trouble).
Then all you need to do is find and fit the appropriate RCDs. The EVSE may include one, and should also protect against high levels of dc (but they might not have got around to that by January 1st, when 18th Edition comes in).
All of which is too complicated for 100% compliance, so we should expect corners to be cut and users to get injured in some installations. The best thing to do is to comply as best you can.
Who needs an expensive EV charging course when you’ve got JW?
Hi JW, big fan, planning on doing the update for amendment 1, any time soon?
WE ARE VERY LUCKY HERE WE HAVE VERY DAMP DEEP CLAY THAT MAKES A BEAUTIFUL EARTH
Hi John have you ever heard the expression a drawing is worth a thousand words can you please do an add on to this video drawing out the different earthing systems and charge points showing the entire installation on one sheet of paper for each of the earthing systems ..... Pretty please
Only if we can have a picture of a cow, JW.🐄
A picture paints a thousand words. He has videos explaining all earthing arrangements 👍
I use these videos on electrical manuals to fall asleep to.. lol so far my record is 7 mins 40.
Do these regulations say anything about so called Granny chargers?
No, BS7671 only covers fixed wiring installations.
Isn't only considering the installation load kinda suspect? Even if you did manage to get the electrode resistance in the sub ohm range?
If you have TNCS, your neighbours probably also have TNCS, In the event of a pme fault, everyone on the street could be affected.
Problematic because they also share water+ gas pipes with you, that may be earth bonded.
If the PME fails upstream of all of you, their installation current could flow to their pipes, underground, into your pipes,into your earth, and Into your massive earthing mat, could it not?
If everyone had such an arrangement, sure, but if you're the only one, you suddenly become the prime fault path for the entire street.
Not to mention the hundreds or thousands of amps of fault current flowing continuously through pipes carrying flammable gas, even if you could get the electrode to the milliohm range.
That doesn't seem particularly safe.
If people can be bothered unlike most of the people I see installing EV points (no TT on TN-C-S) grab your self a copy of the IET code of practice for electrical vehicle charging.
Very good book with out the jargon of BS 7671.
If you really don’t understand why your installing it on a TT system don’t install it !!!!!!
Treat EV points just like a caravan hook up!
@@Beariam24 Almost, but different regs. So for EVs you can (in theory and at great expense) do things that aren't allowed for caravans, like use PME. And EVs need a Type A (or B) RCD whereas a caravan only needs a Type AC. And you don't want a 16A Commando socket for an EV - you need a Type 2 EV outlet because it can deliver more power (if your installation can cope) and it can have a tethered lead (much more convenient). An EV outlet includes a communication link with the EV, which will become more useful as the technology develops, a Commando socket just has power and earth. Some EV outlets have the ability to send only surplus solar power to an EV, a Commando socket is either full on or off.
So a caravan hook up doesn't meet the regulations for an EV unless you upgrade the RCD (it will work, but it isn't safe because a Type AC RCD may not trip when it needs to).
JP F hi
I didn’t mean use caravan hook up for charging EV cars?
I was trying to say just treat EV chargers like a caravan hook up for earthing reasons.
EV chargers can only be on the PME if it is within the building eg garage. Not out side.
As for RCDs yes that’s true but most chargers come with this preinstalled so that is here nor there.
Also caravan hook ups and EV chargers are the same regs.. BS7671
@@Beariam24 Agreed, normally the earthing arrangements are the same. But in my installation I have certain things that have to be PME and others that have to be TT and they are within touching distance, which isn't allowed. So I am very sensitive to the small differences between regulations 721 (caravans) and 722 (EVs) because the differences look set to cost me time and money.
Hi John - Great video. Would be good to get your thoughts on the Zappi 2 charger in light of these regs and this teardown video: ruclips.net/video/gwmiGf6tChE/видео.html. Thanks
At the date of this comment, such things do not comply with BS7671, and therefore must be noted on the certificate as a departure. You are then relying on the manufacturer declaring that the product actually does work as described when a fault occurs.
@@jwflame - Thanks for getting back to me so quickly and sorry for my delay in replying to you. I'm a little confused by your comment. This EVSE which is available as of the date of my original comment in Oct 2019 has a solution designed to satisfy 722.411.4.1 part iii) by separately monitoring L, LN and PME through 3 individual CT clamps and to disconnect PME, L and N through contactors and then requires a manual reset in case of a fault. More details here: More details here: myenergi.com/pen-protection/. Are you saying that this is not yet independently certified as BS7671 compliant (even though it may work in theory) or that it as it is designed it does not and will not comply with BS7671? If the latter, why is this? Or is it something else that makes it non-compliant with the regs? I have no affiliation with Zappi or the video of the teardown.
@@julianbrook9290 it was the former mate, just not certified
Has it been thought about that in the future many households will have 2 or more electric vehicles that may result in them all needing to be charged overnight at 32 amps each, then someone wants to use their 10Kw electric shower, thats really pushing the normal 100 amp domestic supply!
Overnight charge on 2x EV's at 7kW, given an average of 4 miles/kWh... Not many people drive that far each day. Average daily drive is 22 miles
Agree that is the reality Hugh but the regs, as pointed out, state clearly the full cct current is to be assumed. And Richy is being generous with the assumption of two vehicles, many households have more. Life could get interesting for suppliers.
Whole house amperage monitor clamps wirelessly tied to the car charger would allow for continuous adjustment of draw to prevent overcurrent on the main.
I would need that because everything in my house runs on electric.
WELL THAT IS DOWN TO THE SUPPLIER THEY WILL HAVE TO RETHINK INPUT AS 100 AMPS IS NO USE
TO ME
RUN YOUR OWN GENERATOR
@@dorsetengineering Unless the EVSEs are smart-i.e., either modulate or take turns-the peak current is the peak current. As the new regs make clear, you can't assume diversity. Plug 'em in and watch your house pull 64A.
You can tell the person that created that earth rod reg with the 2.5 ohm resistance value has no kind of practical experience! how ridiculous!
I guess some people will have a big garden with a garage far away from the house so they would need earth rods then as well as rcd or additional large earth cabling costing a fortune
Bring back the galvanised milk crates!!!
i not an electrician but sounds nearly impossible to do correctly