Good morning,
Sorry, but i have to ask why you don't just change the single socket in the loft to a twin RCD socket ? It's perfectly acceptable and more cost effective. Fit a good quality plug and use 1.5mm flex to the heater (this is fitted as standard) as i have already said the heater is possibly class 2 (double insulated) and does not require an earth.
You'll have it fitted in 1hour
Kind regards,
DS
Yeah that's what I meant. I don't know why last night I said he'll probably put an RCD FCU upstream of the socket. I'm very sleep deprived.
If the heater's on a plug and there's still only that one socket on the spur then an upstream FCU is unnecessary. He is just going to change the plug socket to an RCD one, as you said.
Quickie. The longest part will probably be him trying to successfully feed the cable through the stud wall.