Wiring requirements in anticipation of charging point......

[PurpleFox]

Hi

I am in the process of having some building work done as well as a new driveway and would like to put in a cable to enable a charge point on the side of the house in readiness for an EV later in the year.

I did some google based research and I intend to lay a 10mm SWA cable underground from the charge point to the consumer unit area in the house in readiness for an electrician to connect at a later stage. The run is approx 15 to 20m depending on the route the cable will take.

I thought I would have covered everything with the installation of the above but it seems there is some confusion (for me anyway) with regards the earth connection. I have a TNS supply, so the main earth for the house is connected to the sheath of the incoming cable which would appear inadequate for an external charging point.......?

A weekends googling has confused me further, some of what I read suggests an earth rod near the charge point, some people say a single earth rod will pretty much do nothing and you need 2 rods at minimum or possibly a mesh buried, others saying the regs have changed and this is no longer required.

Contacted two electricians this morning and one had never installed a charge point the other said he didn't see an issue connecting to the house earth via the SWA but this is contrary to what I have read.....


Is anyone able to advise on what they have in terms of earth on their own installs or any electricians able to comment further? If an earth rod is required I can quite easily put one in and an inspection hatch at this point before the new drive is put down...

Thanks in advance.

[Baldchap]

I used these guys for the install at both our old house and the new house after a move:

https://mcwelectrical.co.uk/car-charging/

Both quality jobs and they were recommended by Tesla. The owner did a site visit before the install in his Model S, which is irrelevant to this conversation but was a talking point.

[Nick928]

We are an OLEV approved chargepoint Installer.

You’ll need a 6mm cable (armoured if installed as described) between the supply and the chargepoint, you will also need an earth electrode for the chargepoint. The option/get out clause to connect via the house earthing conductor was removed in the last amendment of the wiring regulations.
There are complications if there is metalwork in the chargepoint location but that’s a little much for this post.
Single rod should be fine, whoever installs the rod will test it to be sure.
Don’t overthink it, the installer will verify it’s all same when the chargepoint is installed.

[PurpleFox]

Thanks very much for the replies - much appreciated and very helpful.

I think you are right, I am over thinking it....but still have one final question......if the chargepoint is connected to the earth rod then what happens to the earth in the SWA? Is that connected inside the house in the normal way but not connected to the chargepoint?



Thanks for the link to MCW but unfortunately not local.

[essayer]

AIUI the earth from the house supply isn’t connected.

[ruggedscotty]

Trouble with electric car charging is that there are a number of issues that the new regulations bring into the fold.

A type of RCD is specified that is sensitive to dc leakages, the type of leakages that can develop on charging systems. one of the issues with these dc leakages is that it can blind other rcds in the system.

Oh and this new technology doesn't come cheap...…

Also 13A plug socket arrangement isn't designed to run at 13A for long periods so they are saying that plug sockets designed for continuous 13A draw should be used.

https://www.sparks-magazine.co.uk/sparks-blog-ev-c...

https://eocharging.zendesk.com/hc/en-us/articles/3...

https://www.ukpowernetworks.co.uk/internet/en/have...

[PurpleFox]

Thanks for the replies....and bed time reading.

[SpikeBmth]

As per the sparky above, I did a new drive and wall charge point recently.

6mm armoured cable from consumer unit to wall pod, and an earth rod outside.

This Rolec pod I had fitted has the option of a 13 3pin plug, which can then be upgraded to whichever type of car plug you need.


We just connected the armoured cable earth, and sheath together to the house earth , and the charge point earth to the earth rod.

[Boxbrownie]

ruggedscotty said:

Also 13A plug socket arrangement isn't designed to run at 13A for long periods so they are saying that plug sockets designed for continuous 13A draw should be used.

UK supplied “Granny Chargers” are specifically designed to draw only 10 amps.