Apologies for my apparent flippancy @UKPN: I asked if I’d missed anything- you said earthing.  Thanks. Current garage electrics (from the ‘70’s I guess) take their watch from the casing of the metal fuse box attached to the garage wall. Same situation in the office.  There is currently no earth rod.

Sparkingchip‍ you asked inside or out for the EV charge point, can you explain the reason for your question please?  I’m here to try to understand my options, your experience and insight would be invaluable to me please.

Thanks | Paul

A quick question, what kind of SWA is it, PVC or XLPE? This is partly in response to Chris above although I am not concerned by either. It is either table 4D4A or 4E4A, and the buried section operating temperature at maximum load. It could get to about 74C with PVC cable, the effect of which is pretty much negligible, and such loading (with diversity) is very unlikely. More modern cable will be XLPE. The heating time to this temperature will be several hours, and the assumed soil is at 20C which is unusually high at burial depths. Clipped direct either cable is satisfactory.


Regards

David CEng etc.

In answer to the Earthing question I suggest that the whole garage be made TT, with whatever isolation of external water pipes is necessary. It has to be for car charging (at least in premises like these), and multiple Earth systems in the external installation are not permitted due to proximity. It is certainly best too for the hot tub, and anything else used outside.

davezawadi (David Stone)‍ the SWA is most likely PVC. It was installed in about 1972, and is black. I can’t see much of it and can’t find a BS marking unfortunately.

Thanks davezawadi (David Stone)‍ for the Earthing suggestion.  This should be fairly straight forward I think, as the existing earthing in the garage is separated, so would an earth electrode at the garage do it? I don’t believe that there is any extraneous conductive material, but I’ll check.

Too late, Paul, the old dinosaurs are coming out of their coffins and already beginning to talk about  DNO earthing which most of them have limited knowledge. EV? this will be your worst nightmare, you will hear about shocks from outside taps, loads too great for the DNOs network, Earth rods, tingles from the car body, shocks even from the ground around the car. They will say you must dig up the drive and fit an earth mat, They will involve installations which are far removed from the given task. Many of them will remind us (again) of their life stories and you can get an idea how far that goes back when the 13th ed wiring regulation is mentioned, There will be posters who will tell you PME is not safe and we should go back to the 1950s type of earthing, There is even a guy who contributes to the IET EV Code of practice, (99th ed) yes they are having a little difficulty getting it right! £102 + VAT (discount for members.) Although IET claims to be up there, in the industry the latest fiasco being "AUTO SAVED". Get out now, Paul, Go on PM to me, save yourself a breakdown.


Regards UKPN

UKPN‍ i tried the PM but it just fails ...?