..... not again, they shout ...
Gentlemen, I'm new to the group and have read with interest loadsa
stuff about bathroom electrics.

Situation:
Mira Advance (9K) - 45A switch outside bathroom - 6mm twin & E cable -
45A MCB on the board. Earth connected at the board.
Cable run (old house, 9 foot ceilings, board in the middle room):
vertical, clipped, up to attic - about 5.5m, straight across attic
(lying on the floor) - about 10m, down to switch for shower - about 1m.

I was advised (about 2 years ago) that 6mm was ok up to 16m, and I'm
close to this, maybe a bit over.

I now notice that the cable gets warm (!); standard teenage daughter
shower (30 minutes...) gets it warm enough to bother me.
Full inspection of the cable, terminations etc shows no faults.

Looking through your site gave me a lot of info, but 3 questions.
1) should I go to 10mm cable ?
2) I have purchased a 30mA RCD - but after reading about 'nuisance
trips' etc should I go for bigger ?
3) bathroom bonding is all ok, but one article recommends 'thickish'
cable for the secondary bonding line back to the board. Do I then
assume that the cable built-in earth wire ain't enough ?

Any comments/advice appreciated.

FYI I am a marine electronics engineer and as such cover all the
electrics on board (up to the 6.6KV stuff). However, we work to
different regs - and basically just use armoured 10mm as a minimum
size.

Thanks in advance
Peter Owen