by ericmark »
Fri Mar 20, 2015 11:26 am
My first thought is the sink is live and by touching it you are earthing it and so tripping the RCD. Possibly nothing to do with boiler could be grinder or similar causing problem.
Problem is to test we use a special meter that uses 500 volt to test so it's not really a DIY job.
Since the plumber will not likely have the meter required it will likely need an electrician best as already said is some company who has both be it Home Serve, British Gas or any other does not matter but some one who has both gas fitters and electricians is required.