Home charger cable requirement

[George Shagger Smiley]

All

we just moved in to a new build.

Garage is approx 8 meters from the house at the end of the garden.
Total distance to outside mains feed is approx 15 meters.
We have a 16 amp circuit into the garage using I believe 6mm wire but will need to confirm

If it is on 6mm cable, can I get the main circuit breaker upgraded to 32a, add a 2nd consumer board in the garage and then run an EV charger from this (the only requirement in the garage is for a light circuit and an occasional use socket)

[Uncle boshy]

You need to speak to a sparky, but probably they will recommend 10mm and go from the meter if you have an outside one.

Just had mine done this week, I dug the trench across the lawn to the garage, about 6m they supplied the 10mm armoured cable, added very little additional cost to the install.

[George Shagger Smiley]

Thanks

That’s probably the best option except will need to rip up the path to do it

As it happens our boundaries go to the edge of the pavement (approx 3ft) beyond where the fence ends and is landscaped so I could probably go that route and then clip to the house wall

[LordFlathead]

George Shagger Smiley said:

Thanks

That’s probably the best option except will need to rip up the path to do it

As it happens our boundaries go to the edge of the pavement (approx 3ft) beyond where the fence ends and is landscaped so I could probably go that route and then clip to the house wall

The calculations are based on type of cable, the amount of cores, length, and whether it is clipped to surface or buried so you will need a sparky to calculate that. Rule of thumb is that 18th Edition states charging point to have extra earth when run with SWA cable. If you ran in a 10mm SWA along with a 10mm earth then there is zero likely-hood of it not being sufficient and it could allow for future charger upgrades. I have two EV charger points at home, one contractor ran it in 6.0mm SWA and the other shorter run was done in 4.0mm FT+E as the cables went under the floorboards and out to the front of the house via the living room. Even though I am a sparky by trade, the grants enabled me to get the work done for free.

[George Shagger Smiley]

Cheers!

I think my biggest issue will be channeling under the newly laid path (forgot to ask before it was laid)

Is there anything against clipping to the fence?

[LordFlathead]

George Shagger Smiley said:

Cheers!

I think my biggest issue will be channeling under the newly laid path (forgot to ask before it was laid)

Is there anything against clipping to the fence?

No, cable can be clipped to a fence as long as it has the correct mechanical protection for the location. It's in the regs book. Personally I wouldn't use anything other than SWA for a charge point.. and then you have the highly visible earth wire clipped to the SWA.

[George Shagger Smiley]

Cheers I thought so especially with swa it’s just Pod-Point insist if I go with their install it has to be a trench

I’ll look at different routes to get power to the garage and weigh up the options

[johnnyreggae]

Can you not just use the existing 16a supply and a slower 3.7kw charger ?

[inabox]

LordFlathead said:

Rule of thumb is that 18th Edition states charging point to have extra earth when run with SWA cable. If you ran in a 10mm SWA along with a 10mm earth then there is zero likely-hood of it not being sufficient and it could allow for future charger upgrades.

Not wanting to argue, but I can't find this in my regs book or c&g 2919 book and now I'm worried I'm missing something. Are you talking about an extra earth separate to the earth you'd have in 3 core swa?

[No ideas for a name]

inabox said:

LordFlathead said:

Rule of thumb is that 18th Edition states charging point to have extra earth when run with SWA cable. If you ran in a 10mm SWA along with a 10mm earth then there is zero likely-hood of it not being sufficient and it could allow for future charger upgrades.

Not wanting to argue, but I can't find this in my regs book or c&g 2919 book and now I'm worried I'm missing something. Are you talking about an extra earth separate to the earth you'd have in 3 core swa?

A new one on me too... Maybe I am missing something.
As I understand it, two ways of going...
a) three core SWA including earth
b) two core SWA plus a TT earth at the garage end.

IANAE

[LordFlathead]

The changes are listed in the Amendment which is not part of the 18th unless you have subscribed to received the amendments.

Amendment 1- Section 722.

Regs recommend an earth rod (hence the need to take an external earth from the charger to the rod - else you will never meet the 2ohm calculation). It also mentions a mythical disconnection device that doesn't actually exist yet. Pod Point addressed the issue with their new charger which meets the regs by clever trickery, but none the less is approved.

Details of the Pod Point work around is detailed here:

pod-point.com/electric-car-news/earth-rod-details

The amendment is vague but its clearly written. John Ward covers the earth rod and mythical device here:

youtube.com/watch?v=jHjoRkmmBGY

[No ideas for a name]

I think I misread what you had written...
I took it to mean you thought that a separate earth cable should be run physically along the whole length of the SWA presumably back to the cut-out earth or CU earth (PME).
I think I should read it as a separate earth is necessary.

I am in the middle of a general upgrade of services here, and my plan is currently to use a live and neutral connection, and pick up an earth from an earth rod at the remote end of the cable... In that case it will have a separate earth running next to the SWA for the last few metres.

It seems a bit of a nightmare as no two electricians seem to agree on the best practice for EVSE.

Far be it from me to question the PODpoint design, but it seems to rely on simultaneous disconnection of live, neutral AND earth by using mechanical relays (in series for double reliability)... I am not so sure that is 100% fool proof having come across welded contact before now. Small chance, but then there is a small chance of a neutral fault too.

Edited by No ideas for a name on Thursday 4th March 19:42

[George Shagger Smiley]

If I keep the charger inside the garage does that overcome the earth rod issue?

[LordFlathead]

No ideas for a name said:

I think I misread what you had written...
I took it to mean you thought that a separate earth cable should be run physically along the whole length of the SWA presumably back to the cut-out earth or CU earth (PME).
I think I should read it as a separate earth is necessary.

I am in the middle of a general upgrade of services here, and my plan is currently to use a live and neutral connection, and pick up an earth from an earth rod at the remote end of the cable... In that case it will have a separate earth running next to the SWA for the last few metres.

It seems a bit of a nightmare as no two electricians seem to agree on the best practice for EVSE.

Far be it from me to question the PODpoint design, but it seems to rely on simultaneous disconnection of live, neutral AND earth by using mechanical relays (in series for double reliability)... I am not so sure that is 100% fool proof having come across welded contact before now. Small chance, but then there is a small chance of a neutral fault too.

I'm pretty sure there was also another comment in the Amendment about a separate earth too.. cannot find it now.

Every sparky had a different opinion when we discussed it and the issue will not go away until the clarify it. I also have reservations about welded contacts - do you remember when the Rolec charger MCB's were burning due out due to poor Chinese components?

https://www.speakev.com/threads/rolec-charger-dang...

George Shagger Smiley said:

If I keep the charger inside the garage does that overcome the earth rod issue?

Good try Unfortunately the regs are specific about the device (EV Charger) not the location. The earth rod was deemed necessary in case the equipment lost a neutral, therefore it would not comply in fault with the max 70v requirement already set out.

Either way it is a mess. My advice would be to email 3 different EV charger installers, and ask them how they deal with Amendment 1 if no earth rod is fitted. Even if they don't agree, you will then have a recorded reply to a question that no one really knows the answer to.

[inabox]

Ah, sorry, I thought you meant something other than a rod as well.

Some charger manufacturers are now stating they don't need rods, there's isolating transformers or rodding the met as well.

It really seems nobody was quite ready for it all