EV charger causing ground overheating

redfox88 · Jan 8, 2023

Had an EV charger installed in July last year. It’s wired directly off the mains.

Since end of November anytime I plug the car in to charge, the earth/ground wire in the cabling in other appliances in the house is overheating and melting components of the appliance until the main RCD trips.

Has anyone ever seen or heard this happening before and what could be happening?
Even appliances isolated by switch fuses, when off are getting impacted. It’s concerning.

Electrician has been doing tests but is not quite sure what could be causing the fault

redfox88 · Jan 10, 2023

New fuse and meter supplied and readings they’re getting all good.
Their only comment was on the earth cable going from our unit into theirs, that it was too small but not major. Something to fix whenever electrician is out again

Lucien Nunes · Jan 10, 2023

Good stuff. So that leaves the question of whether any of your wiring was damaged by the diverted neutral current. What were the original symptoms exactly?

redfox88 · Jan 10, 2023

That will be the next step yes. Initial assessment only shows damage to one particular outlet feeding one particular gas boiler appliance.
That appliance should have been earth bonded but it wasn’t. Perhaps why it was the victim or some other strange reason.
Will get that bonded, earth swapped at the meter and maybe a full survey of the inner set up. Electrician wants to rewire the board too and feed 6mm cable into the kitchen as everything bar the oven seems to be running off 1.5mm. Not sure if that’s from previous diy rewire or if it’s original cable.

The main thing is that this major issue is solved now. Takes the pressure off a little and can sleep a little better.

Any tips for what I can and can’t do to repair around where they’ve installed the new equipment?
The backer board is hideous and there’s still gaping holes around it

P.S thanks to everyone’s input on this thread. Ye saved me an absolute headache

littlespark · Jan 10, 2023

Would have liked a service isolator fitted to make it easy to change that board in future.

LastManOnline · Jan 10, 2023

nicebutdim said:
Going to tag @LastManOnline in this as I'm certain he'll be interested in learning more about it.

Completely in agreement with all previous comments regarding DNO,s neutral.Its pretty certain that this house still has metallic services which are giving an excellent return path via the neighbours bonding.

Lucien Nunes · Jan 11, 2023

That appliance should have been earth bonded but it wasn’t. Perhaps why it was the victim or some other strange reason.

It's a likely contender if it is connected to metallic water or gas mains that were providing the best earth path after the CNE broke open. As you say, adequate main bonding would then have prevented damage to the wiring by diverting the current along a much heavier conductor. But... would you have discovered the problem in that case, or would the pipework have been left carrying the entire house load current for the foreseeable future?

Some of us here are not huge fans of TN-C-S, even in its PME guise.

redfox88 · Jan 11, 2023

We also found that when we had the combi boiler installed early last year and new pipework done to meet spec, that the gas engineer never did any earth bonding on those pipes, nor did they say anything about needing to do it.
We also don't believe gas is earth bonded at the mains, despite certs from electricians, including more recently the EV install cert, claiming it is.

Strangely enough, networks called again today to upgrade the meter they installed yesterday to a new smart meter.

Recommendation again is to attach more sufficient earth cable from us to them, but also replace the black and red mains cables, the luxury for which will cost €160 for them to call out while that work is being carried out...I think that's what I read from the conversation any way. But he said the red and black were large enough for this not to be done immediately, although its near top of the list now with everything that's happened recently

Lucien Nunes · Jan 11, 2023

Under the current regs, when all relevant circuits are RCD protected, the requirements and necessity of supplementary bonding e.g. around the boiler are largely eliminated. But where there are extraneous metallic service pipes, which it seems you might have, main bonding is mandatory and all the more so with TN-C-S supplies.

plugsandsparks · Jan 11, 2023

Not withstanding what was a dangerous installation regardless of the EV charger, am left wondering why the EV charger did not detect an open PEN and shut down or at least there should have been a rod for the EV charger.......... think the OP would do well to get an electrician to go through the install with a fine tooth comb

Lucien Nunes · Jan 11, 2023

From the charger's point of view, it wasn't open-circuit. There was still continuity, just via the wrong conductors. There would have been extra voltage drop on account of their smaller CSA but perhaps not enough to signal an abnormal condition

Lucien Nunes · Jan 11, 2023

Deleted... duplicate post

plugsandsparks · Jan 11, 2023

Suppose it depends how it has been implemented in the EV charger. With what the OP was saying about hot earth cables around the property, i would expect to see unusual voltages and currents as measured at the EV charger, The Zappi for example has that many reference points built in to the charger that it has occasion shut down when there was no PEN issue, lol - Still think its one to note

Risteard · Jan 13, 2023

redfox88 said:
New fuse and meter supplied and readings they’re getting all good.
Their only comment was on the earth cable going from our unit into theirs, that it was too small but not major. Something to fix whenever electrician is out again

The EV chargepoint shouldn't have been installed if the main protective conductor (neutralising link) was undersized. This should have been rectified first.

Risteard · Jan 13, 2023

plugsandsparks said:
Not withstanding what was a dangerous installation regardless of the EV charger, am left wondering why the EV charger did not detect an open PEN and shut down or at least there should have been a rod for the EV charger.......... think the OP would do well to get an electrician to go through the install with a fine tooth comb

PEN fault disconnection is not a requirement of I.S. 10101.

davesparks · Jan 16, 2023

plugsandsparks said:
Not withstanding what was a dangerous installation regardless of the EV charger, am left wondering why the EV charger did not detect an open PEN and shut down or at least there should have been a rod for the EV charger.......... think the OP would do well to get an electrician to go through the install with a fine tooth comb

There are differences between Irish and UK regs and as far as I know an earth electrode is required for the whole installation under Irish regulations when a TNCS supply is used.

Risteard · Jan 16, 2023

davesparks said:
There are differences between Irish and UK regs and as far as I know an earth electrode is required for the whole installation under Irish regulations when a TNCS supply is used.

Correct. Every installation requires an Earth electrode.

plugsandsparks · Jan 16, 2023

Just had a browse on some chargers and the Tesla for example would have seen the rod and concluded no problem, assuming Earth fault detection was enabled for that install. I am pretty sure a Zappi would have gone nuts either with under-voltage L-N or N-E v Diff

Interesting though how to melt your house cables,

redfox88 · Mar 13, 2023

UPDATE: came home from a couple nights away to no power in the house. The main RCD had tripped.
I traced issue to blow 3A fuse in the switched fuse spur powering the gas boiler. I replaced the 3A fuse but the boiler didn't power.
Further inspection inside the boiler should me that the small fuse inside the boiler had blown.
And further inspection again showed me cabled inside the boiler had been overheating. The loom connecting all the components was melting, and the cables connecting those components to the pub had been melting too. Absolutely no idea why. Power to boiler is sound and no issues anywhere else on the circuit except for the boiler.
Gas boiler installer and repair guy is calling to replace entire boiler as opposed to just components and wiring from the last time round.

James · Mar 13, 2023

It sounds like a possible fault with the supply N
this may be somewhere along the supply cable or even at the substation.
a call to your energy supplier emergency hotline is the best place to start.

redfox88 · Mar 13, 2023

Again? Really? They've just installed (Jan '23) new fuse and meter joining in new L & N into the house

baldelectrician · Mar 13, 2023

The installer should have confirmed the Ze (external earth loop) with the rest of the property off and earths disconnected. The fact that was all boxed in means this was not done

As a matter of urgency get the main gas and water pipes bondedm this way stray earth currents are likely to go through the bonding and not your boiler wiring loom

I would also suggest you contact the car charger manufacturer and ask them to send someone to asess the situation

I also noticed the EV installer appears to have installed a Hager RCD inside an Eaton unit- not good

RoryDickerson · Mar 13, 2023

redfox88 said:
Had an EV charger installed in July last year. It’s wired directly off the mains.

Since end of November anytime I plug the car in to charge, the earth/ground wire in the cabling in other appliances in the house is overheating and melting components of the appliance until the main RCD trips.

Has anyone ever seen or heard this happening before and what could be happening?
Even appliances isolated by switch fuses, when off are getting impacted. It’s concerning.

Electrician has been doing tests but is not quite sure what could be causing the fault

It's difficult to diagnose the exact cause of the fault without more information, but overheating and melting of the earth/ground wire in the cabling could indicate a short circuit or other electrical fault. The fact that other appliances in the house are also being impacted suggests that the issue may be related to the electrical system in the house rather than just the EV charger.
It's possible that the EV charger is drawing more power than the electrical system is designed to handle, causing a voltage drop and increased resistance in the wiring. This could cause the earth/ground wire to overheat and melt, and could also impact other appliances in the house.
It's important that the electrician continues to investigate the issue and performs comprehensive testing to identify the root cause of the problem. They may need to check the wiring and connections throughout the electrical system to ensure that they are properly sized and installed, and may need to perform load calculations to ensure that the system can safely handle the additional load from the EV charger.
In the meantime, it's recommended that you stop using the EV charger until the issue is resolved to avoid further damage to the electrical system and appliances in the house.

brianmoooore · Mar 13, 2023

Another Bot alert!
..... ......

Risteard · Mar 13, 2023

baldelectrician said:
I also noticed the EV installer appears to have installed a Hager RCD inside an Eaton unit- not good

There is no Annex Zb derogation within I.S. EN 61439 so no conditional short-circuit rating for type tested units etc. so there is no prohibition on that. Of course this is assuming that it had been connected correctly e.g. supplied with tri-rated panel flex outer something similar.

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