New Shower Pump RCD tripping

[mlines]

I have a Watermill 2.0 Bar shower Pump fitted on an RCD.

We have been in the house 10 years. I originally fitted (10 Years ago) an unbranded pump which lasted about 4 years before the bearings/impellor work out, this was fitted to an RCD protected circuit and its death was previewed by the pump cavitating loudly and the trip going. I then fitted a Watermill 2.0 Bar Shower Pump and have run this just fine for the last 5 years until recently when it started cavitating loudly and the trip went. I assumed it was worn out after 5 years of family use.

I have just fitted an identical Watermill Pump and it still randomly trips out. This only occurs when the shower is running, so its shower related but the RCD is the Floor Socket Ring Main (the shower is on a spur from the Consumer Unit).

Where should I next be looking for the problem? Do RCDs themselves go faulty and need replacing? Its a modern consumer unit and none of the other trips go. The Ring Main RCD doesn't trip if the shower isolating switch is off so there is not a problem with another device on the ring?

Martin

 

[Beelzebub666]

To be honest if you don't have any test equipment you should consider hiring someone who does. Any electrician will have an RCD tester, they can also check the cable and advise if you may want to consider sticking this thing on it's own RCBO, which I would do. If you have a lot on the circuit even healthy appliances can add up to an occasional random trip.
Might also be worth looking for a leak of water rather than electricity, into a light socket or junction on the same RCD perhaps.

 

[bernardgreen]

One likely cause is a neutral to earth fault diverting to earth some of the current used by the shower instead of it all going through the RCD's neutral. This will un-balance and trip the RCD.

The neutral to earth fault need not be in the shower circuit for this to happen. It can be on any of the neutrals connected to that neutral bar in the CU.