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I don’t know, but I would be surprised if the car bodywork was connected to neutral and/or earth, it would seem more logical and safer to me for the AC supply into the car and the associated rectifier and transformer to be isolated and built to double insulation standards (a larger version of the shaver socket in your bathroom).
Prepare to be surprised. The charging standards, for better or worse, have specified that the earth in the charging cable should be connected to the chassis of the vehicle.

Unless something is really obviously dangerous and they're blatant cowboys, I'd just trust the experts, that's what we pay them a not-insignificant amount of money for :)
This is half the point here - leaving aside the safety aspects, if you have an OLEV install (and the circumstances require one) you are paying for your earth rod and are being ripped off if the installer doesn't supply one. Or honest installers who quote for doing the job according to specification are losing out to cowboys who quote a lower price and then submit certificates claiming work to a standard they haven't met.
 

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What about something like the Andersen A2 which claims "can be connected to the PME supply" and I believe isn't installed with an earthing rod?

PS. Not an electrician., so please explain like I'm 5 :)
 

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What about something like the Andersen A2 which claims "can be connected to the PME supply" and I believe isn't installed with an earthing rod?

PS. Not an electrician., so please explain like I'm 5 :)
There are a few threads discussing this, but the general consensus seems to be that it's very hard to see how any manufacturer could comply with the regs without using an earth electrode. This thread discusses it with reference to a similar statement from Podpoint: Podpoint, no earth electrode required?
 

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All this talk about banging in earth rods. Sorry this doesn't remotely provide an adequate low impedance earth for the ground conditions in this part of Scotland and I suggest many parts of Cornwall has the same issues.

Suggest you query any cowboy in the doirstep as to the measured impedance he has achieved in the local area before agreeing to the quote. Make measurement of that impedance, by an independent sparky, part of the commissioning tests. This is basic safety and functional stuff.
 

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All this talk about banging in earth rods. Sorry this doesn't remotely provide an adequate low impedance earth for the ground conditions in this part of Scotland and I suggest many parts of Cornwall has the same issues.

Suggest you query any cowboy in the doirstep as to the measured impedance he has achieved in the local area before agreeing to the quote. Make measurement of that impedance, by an independent sparky, part of the commissioning tests. This is basic safety and functional stuff.
What value of Ra do you think is needed in order to be adequate to operate an earth leakage detection circuit/device?

The only case where an "impossible" value of Ra is required (well, near-impossible, as it would need a buried mat of a fairly large area) is that needed to comply with 722.411.4.1 (ii).

If using a TT installation then the value of Ra needed is pretty easily achievable.
 

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What value of Ra do you think is needed in order to be adequate to operate an earth leakage detection circuit/device?

The only case where an "impossible" value of Ra is required (well, near-impossible, as it would need a buried mat of a fairly large area) is that needed to comply with 722.411.4.1 (ii).

If using a TT installation then the value of Ra needed is pretty easily achievable.
I'm not an installer but the majority of the time we are seeing our hardware installed with a single spike. Very occasionally 2. Only once have I seen more than two which was a particularly difficult property built on sedimentary rock.

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There have been other threads on this. The electrician who installed my ChargeMaster unit said that he and his mates were up in arms as it now takes over half a day per installation where earth rods are required and this was affecting their bonus system (mine is in the garage so no earth rod needed).

I plug my motorhome into a garage socket which is far higher risk than charging an EV but of course it is not covered by the Regs.

My letter on the subject was published in the IET magazine with a response from the technical committee who, of course, said it was a safety issue. My question was more about probability and risk and whether the cost is justified.

A bit academic because if you have a PMS system the electrician has to do what the Regs. say. Whether it is worth correcting an older system is entirely a decision for a user but in some cases it may be more worthwhile to invest the money in other domestic improvements. My distribution board, for example, has ancient fuses and no RCD. I have had two fuseholders burn out over the years so an investment is well overdue.
 

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I'm not an installer but the majority of the time we are seeing our hardware installed with a single spike. Very occasionally 2. Only once have I seen more than two which was a particularly difficult property built on sedimentary rock.
Matches my experience.

I last installed a TT system around 5 years ago, and with two rods got Ra down to well under 50 Ohms. The installation would have been fine with just a single rod, and I only doubled up the length because I happened to have spare rods and wanted to try and get Ra as low as I practically could (only because it was a part of my own installation).

The nominal 200 Ohm recommended limit for Ra on a TT installation is more to do with stability than the need to ensure that low a value for Ra, I believe. A 30 mA trip current RCD/RCBO only needs a Zs of about 1,667 Ohms to ensure the RCD/RCBO works OK, without raising the touch potential above the safety limit. I can't recall ever seeing that high a value for Zs, and the worst Ra I've ever seen has been around 300 Ohms. That was on sandy soil and came down after boring a hole with a post auger, filling it with Bentonite, then driving two rods down into it (pretty much halved the value of Ra, IIRC).
 

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We had a resistance of several hundred ohms on a free-standing building at the golf club and the contractor had a devil of a job getting it down to the recommended level. On industrial plants that I designed a bentonite pit was the usual method but in the case of the golf club a very long rod eventually did the trick. Cost us quite a lot in the end because of all the coming and going.
 

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Jeremy, you seem to have answered your own question on what value of Ra is recommended.

Just to remind anyone, Table 41.5 specifies max earth loop impedance (NOT Ra, but with certain assumptions lets take that as a proxy) of 1667 ohms for the sort of RCD under discussion but then immediately states that the resistance of the earth electrode should be as low as possible and also says that values exceeding 200ohms might not be stable etc etc.

So I think we are all saying the same thing by different means, ie the earth electrode Ra needs to be 100 ohms or so, possible lower if there is a chance of it being used by a Zoe, certainly lower for a public charger.

My take on this as stated before, is that a random approach by an electrical installer of blindly banging in earth rods, just doesn't cut it for many UK soil types. Basically, the installer needs to take into account local (sometimes very local) installation experience, OR consult with a specialist such as a lightning protection contractor, OR learn how to design and install earthing systems to predictably achieve low impedance earthing in rocky, sandy and otherwise high resistivity settings.
 

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As someone who's banged in a fair number of earth rods over the years, I can say that the majority have ended up with an Ra of around 50 to 100 Ohms. Sure there have been a few that have been over 200 Ohms initially, but I've never had a problem getting Ra down, normally by just screwing on an extension and driving the rod deeper.

One potential issue is that there will be a lot of electricians around who haven't got much, if any, experience of installing a TT earthing system. It used to be the normal earthing system years ago, especially for anyone living in a rural area, so pretty much every electrician knew all the tricks when it came to getting a decent value for Ra. The last (fairly young) electrician I saw trying to test a TT system had to thumb through the OSG to check how to do it, and even then seemed confused as to the test method to use. When I got my old four terminal tester out it was clear the chap had never seen one. I suspect the loss of experience with installing TT systems may be a fair bit of the perceived problem.
 

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If this was an OLEV-supported install, that's not true. As part of the OLEV paperwork, the installer has to sign a declaration that it meets the IET Code of Practice for EV Charging Equipment Installation, and that does not permit the use of PME earth without earth rods.
Is that still true today, post 18th edition, and if so does this in fact render PodPoint's attempts to invent a magical open neutral fault detector totally irrelevant, if the IET CoP mandates an earth rod anyway?
 

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As someone who's banged in a fair number of earth rods over the years, I can say that the majority have ended up with an Ra of around 50 to 100 Ohms. Sure there have been a few that have been over 200 Ohms initially, but I've never had a problem getting Ra down, normally by just screwing on an extension and driving the rod deeper.

Assuming the soil (geology) conditions allow.

Presumably your experience is over a specific geographic area??
 

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Assuming the soil (geology) conditions allow.

Presumably your experience is over a specific geographic area??
West Cornwall, South West Scotland, West Sussex and West Wiltshire. Worst was dry chalk, best was alluvial clay. Where we are now we're on hard Gault, which seems to be permanently moist and has reasonably good conductivity all year around.

I remain convinced that lack of familiarity with installing TT systems has led to a reduction in experience with installing a good earth electrode system. The DNO don't seem to have a problem when they put in their intermediate earth electrodes. Recently they renewed a lot of power poles around here, and I noticed that they were putting in extra intermediates in at the same time. Seems to have had a beneficial effect, as our Ze has dropped about 0.1 Ohm since this was done (we're near the end of a long overhead run from the nearest transformer).
 

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Good geographic spread of practical experience. Gault (OK IoW specific) is in the range up to 20 ohm.m resistivity according BGS so ties in with your comments but sulphate content can make a big difference, bringing the resistivity down, any issues with concrete attack locally?. I'm guessing some of the West Cornwall sites were challenging but again once shouldn't generalise and the local soil conditions if there is any and shallow geology makes the difference. Fancy doing any TT installations where the geology is Lewisian Gneiss.
 
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