Tripping MCB & RCD Post Plastering

[Bobthebuilder95]

Hi all,

Firstly a bit of background, we are renovating our house and had a new distribution board going from the old Wylex type to a new RCD protected one. All was fine for a few weeks with the new electrics until the plasterer came.

Because the sockets were pre-existing the plasterer just loosened them from the wall for the skim and this has resulted in them getting plaster inside them [see below image] since plastering the downstairs ring main which also powers the boiler keeps tripping either the MCB or RCD with no correlation.

The trips vary from instantly to being hours apart but never goes a full day without tripping. I have disconnected the worst effected sockets to try and isolate the problem to no avail and have also check every socket for loose wires.

Any other easy checks / options?

 

[EFLImpudence]

RCD tripping could be the moisture.

MCB tripping indicates a fault like wires shorting or socket screw squashing a wire.

 

[Bobthebuilder95]

RCD tripping could be the moisture.

MCB tripping indicates a fault like wires shorting or socket screw squashing a wire.

Thank you. Annoyingly as the heating is tripping i cant get it warm enough to dry it out! Not sure the best course of action as no socket looks damp and all are away from the wall so no clamped wires.

 

[FrodoOne]

RCD tripping could be the moisture.

MCB tripping indicates a fault like wires shorting or socket screw squashing a wire.

To reduce the moisture you should brush out and/or vacuum (with a plastic nozzle) all the fittings and the back boxes. (Inspect for squashed wires at the same time.)

You could also use a hair-dryer or similar on each box to reduce any moisture which may be present. You may need to use an extension lead from another circuit if the RCD/RCBO keeps tripping on the one having the problem.

 

[Bobthebuilder95]

Hi, right so all the sockets are now loose from the wall, no trapped or loose wires. All dust hoovered out and yet the rcd and MCB keeps tripping varying from instantly to 1 hour after being turned on! Absolutely stumped!

 

[oldbutnotdead]

Is all your cabling in safe zones? None running near or round corners where the plasterer might have spiked corner beads?

Next trick is remove every socket and FCU from the RFC (make ends safe with terminal block), energise circuit, see what happens. While waiting for results from that test, clean out all the plaster and rubbish from the actual sockets (not just the backboxes).

MCB as well as RCD tripping indicates a gross fault somewhere- for instance an old socket that had been removed, wires terminated in terminal block (or PVC) then plastered in would do it quite nicely.