On 26/11/2020 16:34, Andrew wrote:
On 26/11/2020 08:00, Andy Burns wrote:


There are specific requirements about earthing for EVs, possibly
requiring a separate earth rod, particular RCBO type and carefully
keeping apart the house earth and car earth.

Bugger. Does that mean I would need two separate supplies for EV
and normal garage power (which might include an Air-water heat pump
at some point) ?


Not necessarily. The earthing requirement is for making sure that your
car bodywork can't become live if the supply earth is lost and another
fault occurs at the same time. This mainly applies to TN-C supplies
where earth and neutral are combined, and isn't a problem with TN-S
supplies. In any case, many EV chargers now have built-in PEN
protection, which immediately disconnects them in the event of such a fault.

As to whether you need a separate supply cable, that will depend on the
capacity of the existing cable. There seems to be tendency to use
oversize cable to minimise the voltage drop and, perhaps, provide
future-proofing. So, if the existing cable is less than 6 mm^2, it might
be marginal.
--
Cheers,
Roger