RCD keeps tripping on a socket circuit!?

[garry94]

When i flip on the ground sockets the RCD keep flipping off, i've unplugged and switched off everything i can find on the ground floor to no avail. the boiler is the only other thing which i can't reach very well. is there any kind of troubleshooting i can do?
the night it went off there was really bad rain, and i thought that the (two) outside sockets could be to blame, but i think they are on the basement sockets circuit.

thanks!

 

[DetlefSchmitz]

Does the RCD feed any other circuits? Think about outside lighting.

 

[Spark123]

I think you need an electrician with an "Insulation Resistance Tester" AKA Megger to check it out properly.

 

[Taylortwocities]

Pay special attention to any place where water and electricity could meet.
Those outside sockets/lighting
Boiler/central heating controls/pumps/valves
Dishwasher, washing machines, etc

Hot tub, sauna, Jacuzzi bath,

You get the idea.....

 

[Iggifer]

I would also be making sure the outside sockets are definitely on the basement circuit, isolate the faulty circuit then go test if the outside sockets are working

 

[bernardgreen]

A very low impedance fault Neutral to Earth on the basement circuit ( outside sockets flooded ) could be the reason the RCD trips when there is a load on any other circuit protected by that RCD. You mention you cannot isolate the boiler supply (*), that small load and possible high inrush current at switch on may be enough of a load for the basement circuit fault to trip the RCD.

(*) not good, there should be an easy to access isolator for the boiler

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

 

[ericmark]

As bernardgreen shows with the diagram there can be a problem with the neutral. Fuse connection units and switches on sockets should disconnect both the line and neutral but this is not always the case.

I was reminded the other day how the 9 volt battery in a multi-meter will often not show up a fault. It required the 500 volt used in the insulation tester to highlight the faults and so likely it's cheaper to get an electrician to test than buy a meter.