KITCHEN SOCKETS tripping RCD

[dpm_dpmartin]

There is obviously a fault on that socket circuit.
A picture of the rest of the consumer unit would be helpful.
Is there an extractor unit above the hob ?

There is an extractor hood, yes - and I didn't buy it or fit it - but I asked them about it and it is not even remotely new. I know that when their tenancy started 3 years ago - this was actually an over-hob light fitting. I may have a closer look at this, I don't think I saw a socket for it.

I will grab another picture of the whole consumer unit too, and come back.

 

[terryplumb]

Anything else electric that you overlooked ?

 

[jj4091]

Outside socket? Outside Fairy lights? Pond pump? Extension lead? Shed?

 

[EFLImpudence]

If the RCD can reset with kitchen sockets MCB switched off and outside lights MCB switch on ,then the outside lights isn't the cause of the RCD tripping.

What about cumulative leakage or higher current flow?

 

[terryplumb]

What about cumulative leakage or higher current flow?

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

 

[SUNRAY]

With kitchen tripping my first port of investigation is always dishwasher and washing machine.
They account for the vast majority, I'd say close to 100% in my experience.

Faulty internal mains filters are the usual cause.

 

[ericmark]

As has already been said, the MCB in the consumer unit does not switch the neutral, and neither do most switches, odd one out is the cooker, that does normally switch the neutral.

But this means you can have a cumulative earth leakage, so even turning only the kitchen on at the MCB it could still be affected but other circuits in the house.

I had the same myself, kitchen tripping, stopped once dishwasher unplugged, resigned to getting a new dishwasher, but tested first, and it was clear, plugged back in, and all still working months later. I will assume some appliance had a failed mains filter component which finally cleared itself, a capacitor likely. As @SUNRAY says.

I have measured all and only 8 mA so just within the 9 mA permitted per 30 mA RCD, but my house has 14 RCBO's so every circuit independent. It does seem the fridge/freezer likely the problem. I am lucky, my fridge/freezer and freezers are plugged into RCD sockets, supplied from the solar panel inverter and battery, so they will still run even with no electric to the house. I used this meter to try and locate the item which had failed, cost me £35, as to if worth having a meter not so sure, as you have not been able to find out where the fridge/freezer is plugged in, so can't really test it even if you had the meter to test with.

 

[dpm_dpmartin]

I'm back, they're in a much better situation now than before.

I firstly took a closer look at the consumer board and immediately saw that COOKER is on a separate circuit to KITCHEN SOCKETS, so I turned the isolator switch back on and the oven and hob now turn on... so she is cooking a chicken.

I then took off the baseboard in the kitchen and, luckily enough, I found a double socket extension under there with a white plug in it going up the back of the fridge freezer.

I unplugged that and flicked KITCHEN SOCKETS - the RCD tripped again.

I then went one step further, I grabbed the plug from the fridge freezer and I went and connected it to a plug, via extension, in the living room and it turned on, light and humming as normal.

So, they have a boiler, they have an oven, they have a hob, they have a fridge freezer (with a trailing wire going across their living room) and they are much happier than before.

Sadly, I am much more confused... more than ever before. I've had an Electrician get in touch who says he can attend in 3 hours, but his starting price is £250 plus anything for longer or materials... I'm wondering if this is the going rate, for a Sunday / emergency. I had hoped for less but I may have to bite the bullet as I've reached the end of my 'skillset'.

I'm now wondering if MCBs themselves can just 'break' for no reason.

 

[dpm_dpmartin]

...as you have not been able to find out where the fridge/freezer is plugged in, so can't really test it even if you had the meter to test with.

I have now done this, and plugged in into a socket on another circuit (SOCKETS GROUND FLOOR) and it is working away happily. I am at a loss (to be fair, I always was).

 

[terryplumb]

Any further info on the extractor ?
£250 ,is that just for the call out ?? Get some other prices. Possibly for Monday.

 

[flameport]

I'm now wondering if MCBs themselves can just 'break' for no reason.

Yes, they can fail.
That isn't the problem here.

 

[ericmark]

I'm now wondering if MCBs themselves can just 'break' for no reason.

That would not cause a RCD to trip, as no earth or even neutral goes to the MCB.

As to £250 for 3 hours, back in the 1980's my time was charged out at £25 an hour, so I suppose for a call-out, it may cost that, but it does seem high.

As to further work by you, this seems to show some shoddy hidden work by the kitchen fitters, but the question is how would you inspect it? The same for the electrician, he can easily show line or neutral earth fault, but you already know that, but the question is where, and can he assess any junction boxes fitted by the kitchen fitters.

All it needs is a slug, spider, or other creepy crawly to have gone into a socket or junction box. You can likely remove sockets and inspect behind them just as easy as he can, you're looking for both creepy crawlies, and wires caught by fixing screws, all it takes is the 3.5 mm screw to hit a wire as the socket is fitted, and then a little vibration over time can finish it off.

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.

You can also use your nose, burn plastic smells, a socket which has got water in it, will likely smell of burning.

If a kitchen unit need removing to inspect behind it, likely you will remove and refit it far better than an electrician in a hurry. Undoing the work top from a cupboard lowing the legs on a cupboard to put it out to inspect, is time consuming, and awkward. So likely the electrician would remove the work top, meaning more work to replace it.

 

[dpm_dpmartin]

Any further info on the extractor ?
£250 ,is that just for the call out ?? Get some other prices. Possibly for Monday.

Thanks for that bit of advice, we actually had a pretty good chat and he explained it's cos it's Sunday and quite a way away. We've now arranged he will visit tomorrow afternoon and the starting cost will be £150.

As I now know the oven works, the hob works and the fridge freezer works (and I won't have to replace any of these items) I feel quite good right now. I definitely can't complain anyway.

Thank you all, here, for your guidance.

I will update you on the result. Fingers-crossed.

On the extractor fan, it doesn't work - but that's because KITCHEN SOCKETS is off... I now recall, back in 2016 it actually was an older extractor, it was then changed to be an over-hob light fitting for a while, and then changed back to being an extractor. So it is the right kind of thing on the correct circuit. I asked if it was fitted by an Electrician was I was told it was. The unknown here is why it all suddenly happened last night, after years, these two pensioners certainly weren't doing any DIY after 21:00, the old boy needs taking to bed each night by his wife.

 

[dpm_dpmartin]

As to £250 for 3 hours, back in the 1980's my time was charged out at £25 an hour, so I suppose for a call-out, it may cost that, but it does seem high.

No, it was £250 starting price and he could be here in 3 hours.... Nottingham to Barnsley. Anyway, it's down to £150 for the first hour now... I don't see a problem with that... when you can't resolve it yourself you have to pay, and it's not extortionate (well, yet ).

 

[terryplumb]

Good luck ,let us know how you get on.