Kitchen sockets MCB tripping - what could/could not be a cause?

[Shooby]

Hi everyone.

A DIYer here, not looking to fix this issue (as the house in question is hundreds of miles away...) but to try and help owner to narrow down possible causes. He has had a sparky in, but problem persists.

He has a kitchen in a flat-roofed extension. There is a 'reception' room in the same extension. His roof has been leaking, and water has come in through a ceiling light in the rec room, on the opposite end to the kitchen. He's having roofers out to sort this...

At the same time, tho', the MCB supplying only the kitchen sockets has started to trip. This is a B32 MCB and has just been replaced by the sparky, presumably to see if the MCB itself was the actual problem. It hasn't - it still trips seeming at random, sometimes during the day, other times at night. When the owner tries resetting the MCB, sometimes - usually - it remains on. He reports that he does notice a spark inside it when he does so...

I asked him to send me a pic of the CU, and that is shown below. I had been assuming that it was an RCD that was tripping due to the leak, but was surprised to be told it's a 32A breaker.

My questions, please, so he can be informed;

1) Will at 32A MCB generally only trip when the current load is exceeded? Ie when overloaded or due to a short?
2) If so, could the leak cause this? Would a leak actually cause a multi-amp short?
3) Any other thoughts?

I will tell him to turn off every appliance in the kitchen the next time it trips and then see if a 'spark' still occurs.

As far as I know, there's no visible signs of the leak in the kitchen, and certainly not at floor/worktop level where the sockets are positioned. He says the ceiling lights in the rec room are still working!

(PS, the CU was replaced a couple of years back. I'm surprised to see it has no RCD. Is this unusual?)

Many thanks for any guidance.

 

[DefyG]

Very Odd that the kitchen circuit is the only one not RCD protected as all the others are RCBO's

A leak could cause a fault to occur that would cause a 32A breaker to activate.

 

[snowhead]

Did the "Sparky" do any tests on the circuit?
Was it the Sparky that changed the 32amp RCD for an MCB, as it seems the odd one out.
It's almost certain the tripping is water related given the circumstances, but everything else needs eliminating.

 

[buzzlightyear]

Very Odd that the kitchen circuit is the only one not RCD protected as all the others are RCBO's

A leak could cause a fault to occur that would cause a 32A breaker to activate.

Looks like the mcb been fitted to stop it tripping, not a very good spark.

 

[Bob Geldoff1234]

The so called sparky should be shot for what he has done.By the looks of it,all of the circuits are RCBO protected.The sparks has removed the RCBO and replaced it with a MCB.
This is highly dangerous.
You have a bad short circuit somewhere,most probably caused initially by the water tripping the RCBO but now has progressed to blasting causing the MCB to trip.
They need to get someone who knows what they are doing.An insulation resistance test would highlight the problem,and then just a matter of time isolating the fault down.
If possible I would tell them to leave the circuit off and run some extension leads until the fault is found.
The water will have run along and down into something to cause this fault.
The sparky who came should also be reported as he's left them in a very dangerous position.

 

[James]

I bet the original socket breaker for the kitchen was an rcbo.
On this assumption, the spark has made the sockets potentially more dangerous.

Is he a real spark or someone from the pub?

 

[buzzlightyear]

Post up where the work is and one of us might assist.

 

[Strima]

There could possibly be a junction or joint buried somewhere in the kitchen that is full of water from the leak. The only way to find the problem is to carry out inspection and testing.

Were any appliances effected by the leak?

 

[Shooby]

Thanks everyone.

Blimey - I didn't notice that the other MCBs were also RCD type! From what I've been told, that B32 MCB-only is an ADDITION to the board - the owner thinks the sparkly separated circuits and added that MCB. But, the owner is not really clued up so who knows.

Hadn't realised the original MCBs were RCD type - that explains such a lot. Yes, not good!

I'll get his postcode. It's in north-west London.

Thanks everyone.

 

[Mike Johnson]

The original's are RCBO's these are a combination of RCD and MCB so more sensitive, that's why the supposition is that it was replaced by the so called electrician with a MCB to prevent the tripping, urgent attention is required if water ingress is the culprit, water has a way of finding a route into any space sometimes rooms away from the actual leak point.