KITCHEN SOCKETS tripping RCD

[dpm_dpmartin]

Start with a socket on the floor, yes the electrician can test, he will select a random socket likely to be half way, and disconnect the cables, and test which side is down to earth, so he then knows which half the fault is in, and he then splits that half in two, but it is rare for a cable to fail, rodents can cause it, but in the main it is a socket which fails.

He explained something like this in my call with him. Thanks. It makes sense. I suppose no-one cares when they know a socket on the floor is going to be hidden behind a baseboard. He also said it would be a rare case where he needed to do any chasing-out of walls.

 

[ericmark]

I was answering another thread, and I realised for a neutral to earth fault with a TN-C-S supply, it would need less than 2 kΩ to trip the RCD and this can be measured with a standard multi-meter, as only looking at 11.5 volts with worse case scenario. And in your case, since the MCB does not isolate the neutral, extremely unlikely an earth - neutral fault.

So one has to look at the kitchen, and try to work out, likely cable route, and which is last and first socket, and break the ring final. So centre section not connected, so without going into the consumer unit you can test CU to first sockets on the ring final, and the rest. You could do a little more, as you can see.

 

[Harry Bloomfield]

but does it matter if I actually remove plugs from sockets rather than just turned them off?

Probably it does.... A fault L to E, or N to E can cause an RCD to trip, some sockets do isolate both L & N, but they are not common, so to be sure - unplug. Once everything is unplugged, reset the RCD, then plug things back in, one at a time, until it trips - then you have found the cause.

 

[dpm_dpmartin]

Probably it does.... A fault L to E, or N to E can cause an RCD to trip, some sockets do isolate both L & N, but they are not common, so to be sure - unplug. Once everything is unplugged, reset the RCD, then plug things back in, one at a time, until it trips - then you have found the cause.

With everything unplugged the RCD can be set to ON, sure, but once the troublesome circuit is set to ON, the RCD trips once more and the MCB goes to OFF. What you have said here makes perfect sense to me, but what's surprising me is that the circuit in question cannot be set to ON even if nothing at all is plugged in. I have identified all sockets as far as I can tell. All are empty. I am not an Electrician, but I know a little more than the folk who have no exposure to this stuff... I am truly scratching my head as to how this situation arose after years of having no issues whatsoever. It is made more difficult as the Tenants tell me they have done nothing different... but, of course, they would (even if they had been doing something).

I need to pass it to someone else, not a hobbyist like me. I'll find out more tomorrow.

 

[pete01]

Did you check outside sockets etc... after unplugging everything I always look outside

 

[dpm_dpmartin]

The property doesn't have any outside sockets. It does have some outside lights, but I was told - here - that would be a red-herring.

With the help received here I think I've reached the limit of what I can - realistically - do. I'm just pleased it's looking like I don't need to replace an appliance (and any spoiled food)... as that was quite a concern. Of course, I have no idea what it'll be now, so...

 

[Harry Bloomfield]

What you have said here makes perfect sense to me, but what's surprising me is that the circuit in question cannot be set to ON even if nothing at all is plugged in. I have identified all sockets as far as I can tell. All are empty.

Then either you have missed something which is still plugged in, or perhaps something on a spur from the circuit, or there is a fault on the wiring, or at one of the actual sockets. A common one, is where a socket faceplate screw, has eventually pierced a wire, to make contact.

 

[Harry Bloomfield]

The property doesn't have any outside sockets. It does have some outside lights, but I was told - here - that would be a red-herring.

That, depends upon whether the outside lights are supplied via the socket circuit in question - do those lights still work, with the socket circuit turned off? If not, the likelihood is that they are at fault.

 

[dpm_dpmartin]

Then either you have missed something which is still plugged in, or perhaps something on a spur from the circuit, or there is a fault on the wiring, or at one of the actual sockets. A common one, is where a socket faceplate screw, has eventually pierced a wire, to make contact.

Absolutely - and this is why I've kinda thrown my hands up in the air after admitting "as far as I can tell". It's not a large space... above the worktop are only 3 x double-sockets, under the cabinets are 2 x double-sockets - one for washing machine and one for the fridge freezer... I can't see any other sockets, after having taken off some baseboard... so, something else is at-play beyond my more than (?) layperson's knowledge.

As they can still heat their home, can still cook and can still keep their food cold... it's more of an exciting conundrum now.

I've got a small suspicion it may be something to do with the overhead extractor they decided to fit. I will make sure the Electrician is aware of this, but not lead him.

 

[dpm_dpmartin]

That, depends upon whether the outside lights are supplied via the socket circuit in question - do those lights still work, with the socket circuit turned off? If not, the likelihood is that they are at fault.

There is a circuit called LIGHTS OUTSIDE as you can see in my picture of the consumer board. Is it right next to the faulty circuit too... but I had assumed it was unrelated and lights are not supplied by the socket circuit in question. I will try to turn on the outside lights... just to know for sure.

 

[ebee]

Still isn't the cause ,a contributing factor maybe.

When looking for a cause there may be several cumulate - so what you are calling not "the" cause could be the last straw that broke the camels back sort of thing (The ten Iron Anvils did not quite achieve it withat that last straw!)

 

[EFLImpudence]

With everything unplugged the RCD can be set to ON, sure, but once the troublesome circuit is set to ON, the RCD trips once more and the MCB goes to OFF.

I am puzzled by this.

What do you mean by "the MCB goes to off"?

 

[ebee]

He explained something like this in my call with him. Thanks. It makes sense. I suppose no-one cares when they know a socket on the floor is going to be hidden behind a baseboard. He also said it would be a rare case where he needed to do any chasing-out of walls.

Yes we sometimes calls it "Divide and Conquer" and could point you in the direction of the fault (or faults contributing) , sometimes you do it and find out theat hey presto it is caused by the first or second thing you would have looked at but sometimes nearer the last few, either way it could well stand more chance of a solution(s)

 

[EFLImpudence]

There is a circuit called LIGHTS OUTSIDE as you can see in my picture of the consumer board.

It also says "+FANS".

 

[ebee]

I am puzzled by this.

What do you mean by "the MCB goes to off"?

Yes we could do with a little more clarity of which is an RCD and which is an MCB and what hapend in which order, helps make the possibilites/probabillities a bit clearer.
If we know which was tried and in which order and the result (and sometimes how long after those actions it occoured too, approxametly)