On 24 June, 14:34, John Rumm wrote:

[snip]

Thanks for all the useful advice John (and others).

on 1mm^2 cable 2m long that would drop 3.3 x (2 x 18.10) = 119 mV total,
or around 1%. So that would be fine.

With lamps that could be up to 50W, then one cable per lamp would be ok
for shortish distances. If you need longer runs (say 5m or more) then
you could go up to 1.5mm^2.

I don't have any 1mm twin and earth at present. I wonder if I can re-
use all the old red+black 1mm I'm ripping out when re-wring? ELV
doesn't have to pass part-P, does it? I can sheath it brown and blue
if they're that bothered.

That's given me an idea...

Cheers,
David,