Following installation of solar water heating, I am removing an electric (3.8KW) shower and replacing it with a mixer shower fed directly from the hot and cold tanks. Because the head of water is only about 800mm, I also intend to install a twin impeller shower pump (in the airing cupboard).
I will be disconnecting the power supply to the old shower back to the isolation switch in the airing cupboard, but will need a supply to the pump and there is no ring main socket in the vicinity to spur from.
Currently the shower is on a separate 40 amp RCD. Could this be downrated and the existing wiring be used to supply the pump or does a new spur HAVE to be taken from a (distant) ring main socket ?