Although I have spent almost forty years in the electronics/control
engineering industry I am not an electrician and, therefore, don't claim
any sort of expertise with domestic electrics. With that in mind, I
would be grateful (as I have been a number of times before) for the
advice of those here with more knowledge and experience than myself in
My first question relates to a problem with our cooker - a bog-standard,
inexpensive Creda 'Expression'. For some little while two of the
hotplates have had the annoying tendency to cause the RCD in the CU to
trip about once in every 5 or 6 times they were switched on from cold
(never if still warm from having been used a short time previously).
I remember, that when doing some PAT testing a few years back, an
incidence of some portable cookers, with similar hotplates, continually
failing insulation tests when cold - if switched on for a while before
testing they would pass ok. Upon detailed investigation, it was decided
that there wasn't really a fault and we just made sure that they were
run for a short while before testing.
With this in mind, I decided that my cooker probably wasn't faulty but
that for some reason when cold there was just sufficient earth-leakage
current to cause the RCD to trip. I therefore decided - particularly as
we intend to replace the cooker fairly soon - to connect it to the
non-RCD side of the CU. I did this about two weeks ago and there have
been no problems.
My question is: was this an acceptable thing to do?
My second question is about earth bonding in a toilet/shower room that I
have built at the rear of my garage. The room contains a shower cubicle,
with 8.5kW electric shower, a toilet and washbasin , and a small
electrical hand-wash unit. There is no hot water supply to the room,
just a single 15mm cold water supply.
Can anyone tell me what type of earth bonding is required?