help identifying wires in my boiler control box

[D_Hailsham]

it has its own 3 amp fuse in the fused connection unit, its just originally fed from the 13 amp fuse for downstairs sockets in the consumer unit

The fuse in the consumer unit should be 32A. Plugs can have a max fuse of 13A

i presume the supply is like it is because its part of the ring main so one is the power in, and the other set is the power back out to the ring main

Looking at your sketch, I assume the item labelled switch is the fused wall switch. If so, you are probably correct. the two cables are just the in and out of the ring.

I am confused when you say it is a switch and then refer to a fused connection unit. The recommended connectors are either a 3A fused spur or an un-switched socket with a 3 amp fuse in the plug.

 

[bhm1712]

sorry im confusing you, my sketch misses out the fuse, the fused connection unit is switched, so there is the fuse and switch, basically it is a 3 amp fused spur with switch.

and my mistake, the fuse in the consumer unit is 32 amp not 13,