any sparks out there? advice please...

[Sidewaze Samm]

Problem:
Last night the RCD tripped and I narrowed it down to the power circuit in the kitchen. But with all appliances unplugged or fuses removed from spurs, the RCD still trips. So I guess there's a fault in the circuit wiring somewhere (been ok for last 20 years). My guess is the extent of rain has got into something under the floor
Question:
Seeing as my spark is in Menorca for 2 weeks, what's the suggested course of action? Do sparks have a meter gizmo thing that can indicate where on the circuit to look for the issue? Or is it really going to be a case of ripping the floor up to look for a dodgy junction box?
Cheers

 

[Jembo]

Not a sparky myself, how old is the house/flat & have you tried the original Water Dispersal agent... WD40?

Typically all cable runs are only joined in wall sockets/boxes for this very reason

 

[john-e89]

Problem:
Last night the RCD tripped and I narrowed it down to the power circuit in the kitchen. But with all appliances unplugged or fuses removed from spurs, the RCD still trips. So I guess there's a fault in the circuit wiring somewhere (been ok for last 20 years). My guess is the extent of rain has got into something under the floor
Question:
Seeing as my spark is in Menorca for 2 weeks, what's the suggested course of action? Do sparks have a meter gizmo thing that can indicate where on the circuit to look for the issue? Or is it really going to be a case of ripping the floor up to look for a dodgy junction box?
Cheers

I’d doubt its weather related Sam, if it is then you’ve got some exposed wires somewhere, which will need dealing with ASAP. Fault finding is really only done with a vault meter, you can run a continuity test with them to find out if there’s a break between sockets etc, or a bad earth. However, if you’re not sure how to do this you can physically undo each socket front, the two little screws each side, and see if there’s a loose wire, or earth in the socket boxes. A long, boring job as you need to keep going with each socket front but it’s free and you might well find a loose live or neutral. If your house, as should be, has separate ring mains for the kitchen start there and do all the kitchen first. Then move to the rest of the downstairs. Then go upstairs. Then if no joy you’ll have to start on the lighting up and down stairs.

Does your consumer unit have separate trips for upstairs ring main, kitchen, bathroom, shower, etc, along with separate lighting cuircuits? If so, try turning all of them off then, everything, then flick each one back on one at a time, that should hopefully at least let you know which area the problem is, so you’ll be able to concentrate on that ring first, say the kitchen only for example, would save you a lot of searching.

I’m not a trained sparky but have done a few rewires and had them signed off by a trained sparky. There may be another way I haven’t thought of but maybe a fully fledged guy will pop along with a quicker solution, but until then you’ve nothing to lose trying my way. Obviously make sure all the breakers are off before you take a socket or light front off.

Hope that’s al least of some help. Best of luck.

 

[enzed4]

Is it hard wired into the fuse box or a plug-in into an existing socket? Meaning, can you swap it out for another to prove it's not actually the RCD? Just in case it's not the wiring itself.
Edit: actually I think if it's an RCD it will be hardwired in, it may only be circuit breakers that can be a plug-in to the fuse box.
And of course, your wiring regs will be a bit different to ours most likely.
Best of luck with the troubleshooting, but don't start ripping covers off unless you are completely confident with electrical wiring, mistakes can be fatal.

 

[PDJ]

After you have unplugged and removed all portable appliances you now need to check if any other devices like cooker hood is hard wired as the RCD will pick up faults across neutral and earth to these need to be physically disconnected and re try

 

[PDJ]

Where are you in the world

 

[Sidewaze Samm]

It's only the RCD that trips, so not a major short that will trip the circuit breaker - and the RCD only trips if the breaker for the power circuit to the kitchen is turned on. Everything is fine apart from that. All appliances have been disconnected in the kitchen, and all sockets and lights around the house have been checked to see if they work, to ensure they are indeed on different circuits. The fault is definitely within the kitchen power circuit.
But if it is such a small loss/drain/short or whatever, that it will only trip the RCD and not trip the circuit breaker, will a volt meter or any other gizmo be able to detect it?
The kitchen has a wooden floor with pipes and cabling in the void beneath, and we have a relatively high water table here, which is what makes me feel it may be more than coincidence that it has been very, very wet over the last few days.
As I already know which ring main is affected, I'm not sure whether there will be a meter that can help locate the fault more accurately - maybe it can tell if a specific spur is ok or not. So while I plug the fridge etc into extension leads and wait for my spark to get back from his hols, I'll check the few sockets in the kitchen for loose connections, just in case. I'm positive all will be fine - I hope I'm wrong.

 

[Sidewaze Samm]

After you have unplugged and removed all portable appliances you now need to check if any other devices like cooker hood is hard wired as the RCD will pick up faults across neutral and earth to these need to be physically disconnected and re try

Ha! cooker hood - I forgot that one. I'll go and try it shortly, but everything else is physically unplugged for portable stuff and fuses removed from switched spurs for the fixed stuff.

 

[markplant]

Do you have another RCD on a different circuit that you could swap, assuming they are the same rating and type

 

[PDJ]

Fuses out is not enough as the RCD will see a fault across neutral and earth you need to break the neutral as well ie double pull switch or disconnect the neutral

 

[Z4 Gaz]

Where is your kettle, could steam from that got into the socket?

Happened to us before, you could hear the socket 'crackling'.

 

[Sidewaze Samm]

Fuses out is not enough as the RCD will see a fault across neutral and earth you need to break the neutral as well ie double pull switch or disconnect the neutral

I thought something like that. Not sure what you mean by double pull switch? So if I disconnect neutral terminals from all sockets, you think that the RCD will not trip, and then connect each one in turn until it trips. Do I have that right? Or presumably better (at least easier) to disconnect each in turn and test until RCD doesn't trip?
EDIT - were you referring to all outlets or just the fused spurs?
EDIT - got it now, double pole switch - makes sense!

 

[Sidewaze Samm]

Do you have another RCD on a different circuit that you could swap, assuming they are the same rating and type

The RCD is for the whole consumer unit, but must be ok as it only trips when the kitchen circuit is turned on.

 

[ph001]

I definitely wouldn't assume the RCD is OK, as they do go faulty in that they can go much more sensitive than they should (e.g. only supposed to trip with >30mA leakage to earth, but faulty ones trip with <1mA leakage). Most appliances do have some leakage to earth (caused by capacitors from the live and/or neutral to ground) so this is definitely a possibility.

 

[noiseboy72]

The kitchen ring will also include ovens and things like igniters for gas cookers. These often have hidden sockets and switches, so might be worth a 2nd look.

RCDs work by measuring the current on the live and neutral and comparing the values. If the difference is more than 30mA the trip will fire. As others have said, they do sometimes go faulty and become too sensitive. An RCD does not have a connection to the earth, so any fault where current is leaking out of the mains cabling will cause a trip

A sparkie will test the trip value and time to trip to determine if it is working correctly. If it's only the kitchen causing the issue however, I would look for wet faults first. Our dishwasher went faulty and this was causing a trip, even when it was switched off. Insects in sockets are another common one, as are chewed cables.

 

[markplant]

Do you have another RCD on a different circuit that you could swap, assuming they are the same rating and type

The RCD is for the whole consumer unit, but must be ok as it only trips when the kitchen circuit is turned on.

Sorry figured you had individual rcds

 

[Sidewaze Samm]

The kitchen ring will also include ovens and things like igniters for gas cookers. These often have hidden sockets and switches, so might be worth a 2nd look.

Ha! Another one I forgot - gas hob igniter. But then that is definitely the lot. Oven is on a dedicated circuit.

 

[TitanTim]

Can't you just ring another electrician, it will save alot of second guessing :?

Tim.

 

[enuff_zed]

My house has an outside light that seems to be wired into the kitchen circuit somehow? Just another guess though really.

Or maybe the garage circuit? If you have one?

 

[Ewazix]

Under counter lighting? It can be the ring main rather than the lighting circuit....... as discovered when swapping a unit and got a belt!

My wife walked in to see what the fuss was, finding me on the floor she sympathetically said "don't touch things you don't understand", which is fair enough concerning the wiring but doesn't bode well for marital relations!

I think Tim is probably right TBH