Bathroom soon to be retiled. No supplementary bonding on anything at the moment. Usual bath (acrylic) plus copper pipes to loo, bath, basin. I understand supplementary bonding needs to include light, the timed extractor and the pullswitch which switches on light and the timed extractor (no isolation switch for extractor is present). In my ignorance, is it possible to supp bond the pipes to the timed fan only and thereby include the switch and the light in the supp bonding?? REASON IS: I dont want to have to lift the floorboards above the bathroom to reach the light and the timed extractor and pipes are all on one wall. i.e. I want to get on with the tiling and not have any surprises when I eventually get an elusive electrician to turn up.