In article ,
"Hugh" writes:
Do electrical regulations allow for the use of twin and earth cable between
an isolating switch and fuseboard?

Yes. Some wiring accessory products might not handle T&E too well,
in particular, getting the cables into separate entry holes without
some length being unsheathed, given the T&E sheath is lost when
you have to separate the cores.

Also, T&E is _very_ much harder to handle than singles of the same
size. I did a run of 16mm² T&E, and getting it to go where you
want, particularly in a confined space, is quite difficult.
Tape over the cut ends, so when it springs back and swipes you
across the face, a piece of sharp copper doesn't slice into your
skin.

Also, for this application, the CPC (earth conductor) probably
isn't large enough. In 16mm², it's 6mm². I don't know what
it is in 25mm², but it might be only 10mm² when you need 16mm².

IME, SWA is more commonly used for such cable runs (but is probably
even harder than T&E to route, and has same issues with cable sheath).

About 15 years ago I had an istallation and which appears thoroughly
professionally carried out -
From meter to isolator - normal tails -
From isolator switch to consumer unit - twin core and earth (like cooker
cable - 16mm??)
If OK, what size cable is appropriate for this normal domestic installation
as I want to move the fuseboard (and change to a split load with RCD type)
to avoid crossing cellar which is occasionally under water!!

Should be 25mm² T&E for a 100A supply, but would have to be
surface mounted. ISTR T&E doesn't come any bigger than 25mm².

--
Andrew Gabriel