EV Charger Wiring

[Peter James]

Hi,

To start with, I will be getting a qualified professional to install my EV charger. However, in preparation, there are some things that I would like to understand a bit about before engaging someone to do this work.

My home was fully rewired in 2019 and hasnt been touched since so is a clean installation.
The meter box is an external recessed white box at my front door with a 100A main "fuse". The 25mm (and 16 mm I assume for earth) tails then run from there to three henley type connectors in my cloakroom (which is in the middle of the house). And split into two consumer units.
I have an attached garage and ideally would like the EV charger to be located on the outside front wall of the garage beside the main roller door.

I do have two spare blanks on one of my consumer units. I am assuming that all wiring can be carried out from my cloakroom and that 10mm cable will be required for the EV.
Will I need a new CU to serve the new EV charger or can this be wired from one of the spare blanks in my existing CU?
If no new CU is needed, will there just be a 10mm T&E cable run from this existing CU to the EV charger.
If a new CU is required to serve the EV charger - would this most likely be located in my cloakroom and take an additional feed from the henley connectors (I assume using 25mm tails?); and then 10mm T&E from the new CU to the charger? Or will the new CU need to be located in the garage? If so, will the supply bacles ceom from the henley connectors? Can the new CU be in the garage, or must it be outside?
Can the wiring just use normal grey T&E or must it be the round black cable I see used in many videos (all wiring will be internal).

Sorry for all the questions and hopefully they are fairly clear.

Thank you to anyone trying to answer.

 

[Murdochcat]

To be honest you really need a site visit from at least 2 sparks .,,..

 

[Peter James]

I know.
I was just hoping to do some basic learning before hand.

 

[AndyPRK]

they will probably use round black SWA cable.

It really depends who is doing it. and how thick the existing cable to the garage is. (When it was installed, did you tell them you may have an EV?)
I would expect a new CU for the EV and new cable to charger

 

[Peter James]

Thanks.
The only cabling currently going to the garage is a ring for sockets and a lighting circuit so nothing that will do. So it will need an additional circuit.
I am guessing that a new CU might be required as you say. If so - I assume it would be sensible to add surge protection in that new CU? If both options are easily available - would it bet better to have the new CU in the cloakroom near where the henly connectors are connected or nearer the charger in the garage? Maybe it doesn't matter and it us my choice (in conjunction with the installer).

 

[Murdochcat]

Btw an EV charger needs a dedicated RCBO and forms fine for the DNO plus the spark will need to give you an EiC and confirmation of part P compliance if you live in England or wales

 

[EFLImpudence]

Btw an EV charger needs a dedicated RCBO and forms fine for the DNO plus the spark will need to give you an EiC and confirmation of part P compliance if you live in England or wales

Would you like to clarify that confusing sentence.

 

[ericmark]

I would assume warning if CU was changed on the cheap with just two RCD's likely will need a new CU, but if fitted with RCBO's then likely OK. And also there are things like loops supplies to worry about, and loads of forms need completing, so questions asked are better answered by some one on site.

 

[flameport]

Will I need a new CU to serve the new EV charger or can this be wired from one of the spare blanks in my existing CU?

In many cases it can be supplied from a spare way in the existing consumer unit - but this depends on what configuration that CU has, and whether parts are available for it.
Plenty of the sling it and wing it bandwagon installer types will not do that and will insist on shoving in another CU just for the EV charging as that is all they know.
Other, far better installers are available.

Can the wiring just use normal grey T&E or must it be the round black cable

Cabling needs to be suitable for the environment in which it is installed so it could be either of those or something else.
Additional cable is usually required for installation load monitoring and internet connection. Some manufacturers make cable with multiple types inside a single outer.

Can the new CU be in the garage, or must it be outside?

Consumer units go inside.

 

[Peter James]

Thank you.

Not sure if these photos help.

The incoming tails are inside the stud wall and enter that square horizontal conduit. They then connect in to the henley type connectors then each split goes back into the wall and down to each CU.

The right CU has spares and is shown below. Doing a quick search shows that MCG RCBOs are still available.

 

[Risteard]

Thank you.

Not sure if these photos help.

The incoming tails are inside the stud wall and enter that square horizontal conduit. They then connect in to the henley type connectors then each split goes back into the wall and down to each CU.

View attachment 387084

The right CU has spares and is shown below. Doing a quick search shows that MCG RCBOs are still available.

View attachment 387082

It MUST interrupt all live conductors though, so a suitable device may not exist. (I believe MCG do manufacture these in a single mod format, but whether they're compatible with the other devices or not I wouldn't be certain off-hand.) Also a surge arrester would be advised.

 

[Murdochcat]

Would you like to clarify that confusing sentence.

For you. No

 

[Murdochcat]

Consumer units go inside.

Not sure i agree with this

There are perfectly acceptable units that are specifically designed for installations outside

 

[Peter James]

DELETED

 

[Peter James]

It MUST interrupt all live conductors though, so a suitable device may not exist. (I believe MCG do manufacture these in a single mod format, but whether they're compatible with the other devices or not I wouldn't be certain off-hand.) Also a surge arrester would be advised.

Thank you. So maybe the conversation I should be having with the installer should include duscussing having an additional separate CU for this and including a surge protector.