Hi, just looking at some electrics which have been installed. Is it possible to reduce cable size on a radial circuit for a load following a fused connection (FCU) unit according to the regs? e.g. 20A MCB ==2.5mm=> [13A FCU] ==2.5mm=> [3A FCU] ==1.5mm=> [Light] The first 13A FCU : SUPPLY: The 2.5mm cable supply and looped out with 2.5mm cable to the next FCU. LOAD: Feeds a fixed appliance requiring up to 13A with 2.5mm cable. The 2nd 3A FCU: SUPPLY: Just the 2.5mm cable supply which was looped out of the first FCU. LOAD: An external light fitting on 1.5mm cable. Is it acceptable that the cable size has been reduced from 2.5mm to 1.5mm for the load from the 2nd FCU? It would seem the 20A MCB is appropriate for the 2.5mm cable and the 3A fuse is fine for the 1.5mm cable. The risk is someone could put a 13A fuse into the 2nd FCU, but then there are many other places in a domestic setting where someone could make this mistake.