Intermittent Tripping

[flameport]

Thank you in advance for any advice.

The extension lead thing will be useless in this case - it's only of use where there are 2 RCDs, and the suspect appliance can then be connected to a circuit on the other RCD.
As you only have one RCD, moving it elsewhere will achieve nothing.

Switching off MCBs will only remove the fault if it's between L&E. Given your description already, it isn't.
Same as switching things off at the socket - most sockets have single pole switches and don't disconnect the neutral.
Items that are plugged in and not in use can also cause faults.

If you want to rule out particular appliances, the only option is to unplug those things and see if it trips,
As your fault appears randomly with several days between trips, that isn't going to do much either, unless you have weeks or months of time to waste on this.

The fault could be one appliance, or several, or wiring damage, or water getting into something, or several unrelated faults which combine to cause the trip in certain circumstances.

The label on the consumer unit indicates it was installed 32 years ago and hasn't been inspected or tested since then. Those gaps between the circuit breakers need to be filled as there are live parts inside.

 

[terryplumb]

The extension lead ,I assumed ,was going to be used to bring a spare fridge and freezer into use ,so the "suspect" ones can be unplugged and taken out of the equation .

 

[crystal ball]

Just to add some historical findings, when I have been called to random tripping problems it is usually water ingress, had a few underfloor JBs affected by leaky joints, then drying out, so all ok then tripping days later. I had to rewire a kitchen to cure the last one

 

[MarcMCFC1986]

Update: I've come home to get it sorted as it's playing on my mind. The side room (which I earlier called the garage) is on the same Socket Circuit as the Kitchen - including the Combi Boiler, so the MCB labelled Water Heater isn't doing anything either.

Also, the Fridge & Freezer that are in there have been left plugged in (virtually empty too) since the last party - so now there are 2 potential Fridges & 2 potential Freezers causing the problem, along with the boiler. My girlfriend's treadmill is in there too, but she unplugs that when she isn't using it, so don't see that being the problem.

 

[MarcMCFC1986]

Just to add some historical findings, when I have been called to random tripping problems it is usually water ingress, had a few underfloor JBs affected by leaky joints, then drying out, so all ok then tripping days later. I had to rewire a kitchen to cure the last one

In regards to water, wouldn't there be more visible evidence of this? Like dark damp patches on the walls etc. Or are you talking one single drop of water getting through a crack somewhere?

 

[crystal ball]

In one instance there was a faint brown stain on the ceiling below, another cause was a slug inside a JB

 

[terryplumb]

Unplug the two " party" appliances. See how you go. If still tripping ,revert to using them and unplug the usual ones. Moisture can be an issue on electrics ,so anything combining the two ,like a boiler ,washing machines etc are equally suspect ,doesn't have to be a deluge .If ruling out appliances doesn't get you anywhere .....get an electrician in.

 

[MarcMCFC1986]

Unplug the two " party" appliances. See how you go. If still tripping ,revert to using them and unplug the usual ones. Moisture can be an issue on electrics ,so anything combining the two ,like a boiler ,washing machines etc are equally suspect ,doesn't have to be a deluge .If ruling out appliances doesn't get you anywhere .....get an electrician in.

OK thanks - they are both unplugged now. The freezer is directly under the boiler, so I guess one drip of water from the boiler, onto the back of the freezer (it is in line with the back of it) could have done it. My girlfriend reckons the fridge and freezer in there have been plugged in for almost a year though, so surprised it hasn't happened sooner if that is the case. Just have to keep fingers crossed that it is something as simple as that!

My head always goes to worst case scenario though, so I'm expecting it not to be that.

 

[MarcMCFC1986]

Another Update: I think - though I obviously can't be sure - that I might have figured it out.

At the back of the house we have French doors, with a flat roof over the top. The drain for the water to come off the flat roof was completely blocked up with mud and leaves, and so it was like a lake on the flat roof, and the water was over flowing and pouring down the wall of the house. Unblocked the drain, all the water came cascading out like Niagara Falls, and now the roof is clear of water.

Photo attached with the area where it was blocked circled. The white frame you can see just to the right of the photo is the frame of the back door leading into the kitchen - so it could well have been getting onto the kitchen circuit through cracks in that wall? Maybe? Hopefully?

 

[terryplumb]

Very unlikely ,in my opinion. Water presence that causes RCD to trip ,would ,more often than not, not allow the RCD to reset straight away ,and would have to dry out. But its not beyond the bounds of possibility.
Has the RCD tripped today ,with all relevant mcbs on ?

 

[MarcMCFC1986]

Very unlikely ,in my opinion. Water presence that causes RCD to trip ,would ,more often than not, not allow the RCD to reset straight away ,and would have to dry out. But its not beyond the bounds of possibility.
Has the RCD tripped today ,with all relevant mcbs on ?

That's the thing - on Saturday night and the early hours of this morning it wouldn't reset straight away, it kept tripping back off until I switched off the Kitchen MCB. Friday I wasn't home when it tripped off so it could well have dried out by the time I got home, and so reset straight away.

Yes all was fine today when I got home from work, everything was still on.

 

[crystal ball]

Very unlikely ,in my opinion. Water presence that causes RCD to trip ,would ,more often than not, not allow the RCD to reset straight away ,and would have to dry out. But its not beyond the bounds of possibility.
Has the RCD tripped today ,with all relevant mcbs on ?

Has it reset straight away though, there seems to a some delay in re setting successfully or have I missed something? any way best to keep an open mind and don't go down too may blind alleys

 

[Harry Bloomfield]

I'm a novice at all this - only been a home owner two years - so not sure what the next step is? I've just ordered this on Amazon (https://www.amazon.co.uk/gp/product/B000RZDNZM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) so I can plug the fridge in, then the freezer, and see which (if any) trips the circuit.

What you ordered there, is exactly what you already have - that switch on the left is an RCD.

RCD's are caused to trip by an imbalance of current, comparing the current passing through the live, with that through the neutral. Idea is - if they are not exactly equal, then current is leaking via some other route. The other route, could be through your body, so it trips to protect you.

What many electricians do not appreciate, is that simply turning things off (either at the socket, a switch, or at the MCB) may not prevent the RCD from tripping, if the leakage is neutral to earth leakage. Such faults, especially if intermittent can be very difficult to find. Begin by unplugging anything which can be unplugged, then see if it still trips. If there is no trip of the RCD, then you can gradually add things back in.

If still trips with everything unplugged, then you need some expert help from someone who knows what they are doing, with an insulation tester. That person is obviously not the first 'electrician' you discussed it with. Common causes are oven elements failing, immersion heater elements failing and water which has got into an outdoor light.

 

[MarcMCFC1986]

Has it reset straight away though, there seems to a some delay in re setting successfully or have I missed something? any way best to keep an open mind and don't go down too may blind alleys

Correct - the only time it reset straight away was on Friday when I'd been at work all day and so could have dried out by the time I got home. Saturday night and last night it didn't reset until I switched off the Kitchen MCB.

 

[EFLImpudence]

Correct - the only time it reset straight away was on Friday when I'd been at work all day and so could have dried out by the time I got home. Saturday night and last night it didn't reset until I switched off the Kitchen MCB.

Then it could, just could, be wet between Line(live) and Neutral Earth (or coincidence).

Any outside lights or sockets on the circuit?

Edited mistake.