Downrating a 6mm cable?

[craigap]

Hi

We have an onsuite electric haower being serviced by a 6mm from a 32A breaker. However the shower is just about to be changed to a thermostatic shower, with light and fan fed the lighting circuit via a siwtch height isolator in the bedroom.

Three things; The cable is routed up the side bedroom wall adjacent to the bed, to a 45A pull switch. We are about to have the bedroom re-palstered and only have 1 twin power socket in the room and have laminate flooring. Can I use the 6mm to feed bedside sockets if it was downrated at the board to say a 16Amp?
Secondly, are Isolator switches made to last as long as general 10Amp switches by being switched on and off daily?
Thirdly, would re-using the 6mm fall under part p or classed al permissable alterations?

Thanks for any assistance.

 

[ajrobb]

I think all work in a CU is notifiable. But don't worry, what you have is ideal for a 32 A radial circuit which can feed an unlimited number of sockets for up to 75 m² floor area.

 

[craigap]

I think all work in a CU is notifiable. But don't worry, what you have is ideal for a 32 A radial circuit which can feed an unlimited number of sockets for up to 75 m² floor area.

So are you saying that I could just keep everything as is and just remove it from the 45A pull switch and drop it in to the first socket, then so on?

Thanks

 

[ajrobb]

The main difficulty will be bending the cable to fit into the sockets. You'll need 35 mm deep boxes rather than 25 mm. You can extend the circuit with 4 mm² cable clipped direct on the surface or buried in plaster but not anywhere else. If you bring the 6 mm² cable into one socket (single or double), you can add one more socket (single or double) on a 2.5 mm² unfused spur.

If you run the circuit in 4 mm², you'll need to keep the cables at least two diameters apart on the surface or one diameter apart in plaster to avoid 'grouping'. That is is the bigger cable diameter or width. Some electricians frown upon burying horizontal cable runs between socket even though it is technically allowed. The other option is to run the cables vertically up to the ceiling then along the wall within 150 mm of the ceiling then down to the next socket.

Another alternative, is that you can bring the 6mm² cable into a 13 A fused connection unit and run any number of sockets on a fused spur using 2.5 mm² cable. But that would be daft if you've got the plaster off.

At least 4 double sockets are recommended for a double bedroom.