bathroom electrics

[frexpt]

We are carving two new bathrooms out of larger rooms and I am trying to do a few bits and pieces myself to keep costs down as much as possible. I have managed to find some neat twin light switch/socket units, as I would like to install a light over the handbasin in each sdb and a socket close by for recharging this and that and to power the wife's hair drier. 

I am aware that lighting should be 10A and the sockets 16A, but will it be okay to use 2.5mm cable for both in this case, or should I use separate feeds?  The switch and socket each has its own input.  I'm only doing a first fix before the plasterboard goes up and will get everything checked out in due course.  However, I don't want to put in the wrong size cable to start off with.

[Badger LX]

I'm not entirely sure what you are asking, but to "tell it how it is"......

Lighting & power (socket) circuits must be supplied separately. You could use 2,5mm² for your 10A protected lighting, but it would be a pointless exercise & a waste of good copper. As you point out, the socket side of things can be done in 2,5mm², with a 16A fuse or 20A MCB (disjoncteur) to protect it (though personally I always run general socket circuits via 16A breakers). The sockets could be run in 1,5mm² as long as they are part of a circuit with no more that 5 outlets on it & the circuit is protected by a 16A disjoncteur (fuses not allowed).

All circuits in a salle d'eau must be protected by a 30mA interrupteur différentiel & your socket(s) are only allowed in Zone 3 & not above a sink. If you have copper plumbing &/or metal window & door frames then don't forget about putting in LEP - liaison équipotentielle.

[frexpt]

Thanks for the explanation.  I suppose I was wondering out loud whether I could get away with adding two 50w halogen spots to an adjacent socket circuit, instead of cabling them separately.[8-)] 

I'd since decided to put the sockets and lighting on individual "feeds".  I'm only running cables from the new bathrooms up into the grenier at this point, so that the joiner can get on with finshing the plasterboarding.  It will be up to the electrician what he does with them from there.  Most of our electrics run from the main consumer unit on the ground floor, up to the second floor grenier and are then distributed around the house from there.  There is plenty of spare capacity for more disjoncteurs on the board.