I have just been talking to my electrician and he asked if the 40 amp commando would do instead of the 32? The other question is what would be a good brand to buy? I quite like the model shown in the Tesla installation guide, but do not know if it is a sufficiently good quality product.
https://www.tesla.com/sites/default...nstall_guide_industrial_socket_blue_DEC16.pdf
I quite like this one as being inexpensive but satisfactory quality:
Gewiss IEC 309 32A Switched Interlocked Socket 240V GW66015 | RS Electrical Supplies
Note that it has to be interlocked (per regulation).
You can also get ones like
this that have space for the RCD within the same housing - but relatively expensive.
I'm not sure what to make of the 40A question - there's no such thing as a 40A commando (they come in 16A/32A/63A sizes). The 32A is the only one for which Tesla supply a 'head' for the UMC to fit it (it would make sense to support the 16A also, but they don't).
If your electrician is not familiar with EV charging, point him at section 722 in the regulations book (which applies equally to commando sockets for charging purposes). In addition to the points we've already covered about RCD and interlocked sockets, there is also earthing to consider. In many cases (but not all) the earth from the house shouldn't be used and a separate earth should be provided for the chargepoint (known as a "TT island", also common practice for garden sheds and the like). Not much extra cost/effort to do it right.
Not in the book but worth mentioning, don't penny-pinch on the cable size to the chargepoint. You might find that, under the most favourable conditions, 4mm² cable might just comply with regulations - and that would be sensible design if you were installing a commando socket for (say) a welder that uses full power only intermittently. For EV charging, you are going to be using it flat out for hours at a time, so stepping up a size to 6mm² is better - it will run cooler and so be more reliable, and the thin wire isn't cheaper in the long run as the cost difference is minimal and soon made up by the extra electricity cost in heating the cable rather than the car.
Finally, are you sure you want to go with a commando socket? All the wiring, RCD, earthing etc. is exactly the same whether you go for a Tesla WC or a Commando socket on the end of it. The Commando socket appears ~£300 cheaper, but only because you got the UMC "for free" with the car. If you intend to leave it permanently plugged in there, then that's fair enough. However, most people want to take the UMC with them for use away from home (hotels, relatives etc, usually with the 13A plug). So if you are also using it as your daily home charging solution you either:
- Roll it up and stash it in the car before setting off every morning. Not fun as the cable inevitably gets dirty over time.
- Take it with you only when you need it, rather than keeping it in the car. Risks forgetting it on the one occasion that you do actually need it.
- Buy a spare UMC to keep in the car. This is actually more expensive than buying the WC for at home in the first place.
Having a dedicated chargepoint at home also means you've got the UMC to use in emergency if it breaks - whereas using the UMC every day you are in trouble if it breaks/wears out.
