Hi , Just got a qualified sparky to wire my new shower , I have an old fuse box rated 60amp I think , Is it ok to make move in the old fuse box by putting two light fuses into the same fuse , thus freeing up a fuse , then fitting a 45amp fuse , and wiring the shower , seems a strange way to do it , I thought you needed a separate box or a new unit 100amp . Who am to question the qualified ? .