RCD Tripping - help!

[Gazza1980]

Hi, hope somebody can help

Yesterday afternoon our RCD tripped and everything went off. We turned it back on and Sockets 13 went down (see attached image). This rules out the kitchen (luckily) and two of the upstairs bedrooms as they are still live. It seems to be the living room and two of the upstairs bedrooms. However, to test which is the offending appliance, I have unplugged every single thing in those rooms, then when I flick the switch up it just goes off - so can't be an issue with any appliance itself (TV, lamps etc).

Where do I go now?!

Thanks

 

[ericmark]

For the 32A MCB to trip there has to be a really bad fault. The RCD may trip on a very small fault. So to start with unplug every item plugged into dead sockets, and ask every one what they were doing when it tripped, look at walls and floors for signs anyone has damaged cables, if you can't see anything try resetting it once, if it trips then really a job for an electrician as your unlikely to have the testing stuff required.

 

[JohnD]

Have you had a water leak, or nailed into a wall?

 

[dannyboi2003]

Have you got any external sockets or outbuildings that are also affected? My thought with the current weather is water has got into an external junction box or something like that.

 

[Gazza1980]

Thanks all. We were literally sat in a room when it went off for the first time. No appliances being used. And although it was chucking it down at the time, I can't see any leaks or anything external that could be affected. Guess I'll have to get someone in to look. Any idea what sort of price to expect?

 

[JohnD]

Have you got any external sockets or outbuildings that are also affected? My thought with the current weather is water has got into an external junction box or something like that.

this is an important question.

An external socket, or an external light, often gets rainwater in it.

So is the question about the nail.

 

[bernardgreen]

It is un-likely that water in an accessory ( lamp, switch, junction box etc. ) would carry enough current to trip a 32 Amp MCB. If there was an Earth in the accessory then the RCD would trip long before the MCB could trip.

It has to be damage to a cable or an accessory.

 

[Gazza1980]

Ok, turns out the pressure relief valve on that side of the house is leaking and actually seeping through the brickwork (massive wet patch on the outside of house, and we have no cavity wall there as the house is nearly 100 years old). Got somebody coming to look at boiler tomorrow, reckons it'll be the PRV and maybe the expansion vessel. There was another downstairs socket in the room underneath the boiler bedroom and the wall does feel damp around it.

Will this dry and eventually be ok or do I still need to get a spark in to check it out?

 

[flameport]

Will this dry and eventually be ok or do I still need to get a spark in to check it out?

It will dry out, but if that is where the fault is, the socket should be replaced.
A high fault current that can trip an MCB is likely to have vaporised metal parts of the socket and left conductive residues.