OK, here goes (and apologies if this is incorrect as i am a newb!) i am finishing off an extension that was added to my house last year. The extension contains an ensuite bathroom, into which I am fitting a spa bath. The bathroom will also have a power shower (over the bath)...the pump for this is under the hot tank in a sperate airing cupboard. The sparky that did the electrics ran a cable from a downstairs ring main to supply the spa bath. I am going to fit a switched fused spur with a 30A RCD (both mounted into the plasterboard bedroom/bathroom wall- facing into the bedroom). The flex from the bath pump will terminate in a waterproof junction box under the bath, then to the RCD. I have also bonded the bath & shower pipes to the bath legs, sink hot & cold pipes and the radiator, using 10mm cable (should be 4mm......but should be no harm!). Does this sound OK??? Do I run the new bonded earth to the earth pole in the RCD (or junction box), or does it need to run back to the existing airing cupboard, where the old pipes are bonded to the immersion earth point? Also, will i need to install a ceiling pull switch for the shower pump (I am going to fit an RCD off an existing spur to power the pump)?? I hope I have given enough info....if not please let me know.