However if you are in the UK do bear in mind that is is now not legal (Building Regs) to DIY in the bathroom.
You need to be a 'Competent Person' or have the work signed off by a Competent Person. If you ignore this and make an insurance claim (or worse) or try to sell your house you may have problems.
T, April 2009
Cheers - thats the answer i needed!
cs, April 2009
You can have the isolator switch outside the bathroom on the wall, or inside the bathroom on the ceiling, operated by a pull cord.
John, April 2009
edit
I can answer this question...
where do i have to fit an isolator switch on my electric shower? ?