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Apologies if this has been posted before but I found this explanation who why earth rods are important for EV charge points: Earth rods - who needs them?

It's aimed at promoting the PEN protection built in to the Zappi unit but does answer the question about why installers are insisting on installing earth rods.
 

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Thanks Barney, interesting info at the link and I've been watching a few YouTube videos on the subject recently. John Ward has some good videos on the various different types of earthing arrangements and dangers of PEN faults (like this one:
).

What I don't really understand is why car charging is much different from say outdoor garden lighting e.g. stainless bollards or recessed lights, or wall lighting with metal casings as well as outdoor wall mounted 13A sockets which as far as I know don't have any special requirement regarding exporting the PME earth in case of a broken Neutral conductor.

I don't think there are actually many (if any) exposed conductive parts on a car, as everything is either plastic or painted or both, so I'm not sure why this is (presumably) deemed a higher risk than other outdoor electrical installations that do actually have exposed metal casings. Although admittedly if the car is wet then I suppose you're more likely to come in contact with water that is also in contact with internal parts so maybe that's the reason.
 

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Zoe GT Line 2020
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Still don't quite understand why my installation last week didn't need an earth rod....

134949


I think there's some magic (mainly the bit in the middle) in the new mini-consumer-unit
 

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Still don't quite understand why my installation last week didn't need an earth rod....

View attachment 134949

I think there's some magic (mainly the bit in the middle) in the new mini-consumer-unit
Mine was like that. They were going to install a CU and earthing rod but instead put in what was referred to as a "voltage regulator". It looks similar to yours but in a slightly different box!
134950
 

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KIA Soul EV 64kWh
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Still don't quite understand why my installation last week didn't need an earth rod....

View attachment 134949

I think there's some magic (mainly the bit in the middle) in the new mini-consumer-unit
Surprised to see:
1) an indoor consumer unit mounted outdoors with no weather protection
2) current regulations require consumer units to be metal cased, not thermoplastic
At least the installer has fitted an Open PEN fault protection device!
 

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I think it's an IP rated enclosure looking at the seal around the switchgear and the clip on bottom of the plastic door.
The regulation regarding non-combustible units says 'in domestic premises', so outside the premises should fall outside the definition. I was interested to look up the data on the Broyce Control LXCVR-EV module shown above, however I cannot find any reference to it on the Broyce Control website or anywhere else for that matter, which is strange.
 

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KIA Soul EV 64kWh
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Mine was like that. They were going to install a CU and earthing rod but instead put in what was referred to as a "voltage regulator". It looks similar to yours but in a slightly different box!
View attachment 134950
The Broyce Control LXCVR device is a voltage measuring device, not a voltage regulator. It trips the contactor (large 4-pole device at RHS) if the 1Ph supply line voltage is greater than 253Vrms or less than 207Vrms. Critically the disconnection includes the Protective Earth conductor
 

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KIA Soul EV 64kWh
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I think it's an IP rated enclosure looking at the seal around the switchgear and the clip on bottom of the plastic door.
The regulation regarding non-combustible units says 'in domestic premises', so outside the premises should fall outside the definition. I was interested to look up the data on the Broyce Control LXCVR-EV module shown above, however I cannot find any reference to it on the Broyce Control website or anywhere else for that matter, which is strange.
It looks like a special version of the LXCVR with fixed trip levels for EV charging applications
 

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KIA Soul EV 64kWh
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According to comments from an electrician elsewhere...

  • The CU is an Elmark IP55 - rated for external use.
  • A CU only has to be meta if it's within the main dwelling.
Don't take anything I say as gospel though - I last read any electrical regs in the late 70s and I think they may have changed a little since then? :)
Ah! I didn't spot the clip & seal on the lid.
I should have realised that plastic is OK outdoors as the PodPoint is made of plastic :)
 

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It looks like a special version of the LXCVR with fixed trip levels for EV charging applications
Yes that makes sense, strange there is no reference to it on the manufacturers website though.
So does such a voltage detection device on it's own meet all the requirements of the specific part of BS7671 for EV charging? From reading the Zappi documentation about their new method and watching various YouTube videos it seems that the issue of avoiding installing earth rod is a little more complex than just monitoring for over/under voltage?
 

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Yes that makes sense, strange there is no reference to it on the manufacturers website though.
So does such a voltage detection device on it's own meet all the requirements of the specific part of BS7671 for EV charging? From reading the Zappi documentation about their new method and watching various YouTube videos it seems that the issue of avoiding installing earth rod is a little more complex than just monitoring for over/under voltage?
According to page 9 of this document it does:

Line over/under voltage is a good indicator of PEN fault
 

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In section A722.4 referenced on that page where it goes into the detail, it states:

Suitable arrangements include measurement of the voltage between either:
a) the circuit protective conductor and a suitable measurement earth electrode, or
b) <reference to 3 phase supply not applicable here>

I don't see an earth electrode, so what are they measuring against in this installation?

There's also a very interesting video here:
showing that depending on which phase your house is on you might not see an under or overvoltage in case of a open PEN conductor even if you are measuring against an earth electrode.
 

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KIA Soul EV 64kWh
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In section A722.4 referenced on that page where it goes into the detail, it states:

Suitable arrangements include measurement of the voltage between either:
a) the circuit protective conductor and a suitable measurement earth electrode, or
b) <reference to 3 phase supply not applicable here>

I don't see an earth electrode, so what are they measuring against in this installation?

There's also a very interesting video here:
showing that depending on which phase your house is on you might not see an under or overvoltage in case of a open PEN conductor even if you are measuring against an earth electrode.
Interesting video, thanks!

Page 10 Clause (iv) relates to 1ph systems and doesn't require an earth rod.
However I think the IET amendment is badly specified and poorly implemented.
The better way to make EV charging safe is for the EVSE & car to be double insulated i.e. no connection to earth. The LV (12V aux) battery is ground tied to chassis but the HV (traction) battery is fully isolated.

So why not fully isolate the car during charging?
This might be a problem for the Zoe which, I believe, uses the motor coils as part of the rectifier circuit!
 

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Evezy referral code: d4113
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This worries me a little bit.
I had my rolec installed by a proper qualified electrician ( recommended to me and has done other work in my house), but maybe hadn't installed a car charger before, I didn't ask him.
The rolec untethered charger is totally indoors and undercover but the car is charged outside (cable fed under gate). The rolec is earthed from the consumer unit but not with an earth rod at the unit. Does the fact that the charger is inside make a difference ie it doesn't need an earth rod? Even tho the other end of the cable will be outdoors.
 

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KIA Soul EV 64kWh
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Section 722.411.4.1 Clauses (iii), (iv) and (v) provide implementation options, and seem to move the burden of responsibility from the standards to the installer and manufacturer. It looks like a knee-jerk reaction to a potential (sorry) risk created by a new use case (domestic EVSE).
The remedy specifies a 5sec fault timeout, which avoid false errors on short duration line fluctuations but does not protect against a lethal shock.
The very same document on Page 14 suggests shorter disconnection times to protect a person touching the vehicle.
This requires an earth electrode and is described as an optional enhanced safety provision!
 

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Discussion Starter #18
I’m no expert on
.
The better way to make EV charging safe is for the EVSE & car to be double insulated i.e. no connection to earth. The LV (12V aux) battery is ground tied to chassis but the HV (traction) battery is fully isolated.

So why not fully isolate the car during charging?
This might be a problem for the Zoe which, I believe, uses the motor coils as part of the rectifier circuit!
I’m no expert on class 2 (double insulation) but I doubt it would be easy. I don’t fancy a car painted with that bumpy paint you see on class 2 street furniture.

Theres more to it than no connection to earth. The car is one big exposed conductive part so I don’t know how you would protect against a fault where it becomes live.
 

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This worries me a little bit.
I had my rolec installed by a proper qualified electrician ( recommended to me and has done other work in my house), but maybe hadn't installed a car charger before, I didn't ask him.
The rolec untethered charger is totally indoors and undercover but the car is charged outside (cable fed under gate). The rolec is earthed from the consumer unit but not with an earth rod at the unit. Does the fact that the charger is inside make a difference ie it doesn't need an earth rod? Even tho the other end of the cable will be outdoors.
The 18th Edition of the IET Wiring Regulations state that for a PME (TN-C-S) installation (most UK houses) if the charger or the vehicle is outdoors then the PME earthing cannot be used for the protective conductor of the car charging point.
So you either need an earth rod or some other means of disconnecting the car charging point in the event of an open PEN fault.
Some charge points have this protection built-in e.g. Zappi, & PodPoint. Sorry, I don't know about the Rolec.
 
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