Round at my brother-in-law's house today. He has an airing cupboard on the landing and inside the cupboard is a fused switch for the immersion heater. Wiring is conventional :- mains cable goes into the switch and flex goes from the switch to the immersion heater. He has bought a digital immersion heater timer from Screwfix so that he can have the immersion heater coming on and going off automatically during the summer months when he doesn't use his (oil fuelled) boiler. He's a bit baffled by the switch and was asking my advice on how to connect it. For a start there are only two connections inside the timer - for live in and live out. No connections for neutral or earth. Also the instructions state that the wiring (in and out) must be solid copper which complicates matters because of the flex going to the immersion heater. So...............how would one go about wiring up this timer between the fused switch and the immersion heater? Any offers? The only way I could think of would be to ignore the advice on solid copper and still use the flex. Have cable from the fused switch into a junction box and then flex from the j.box to the timer. remove outer insulation from the flex and cut the live wire and connect that through the timer - leaving the neutral and earth to continue on to the immersion heater. Seems a bit 'Heath Robinson'ish' however.
Kev