Random RCD Tripping

Seb101 · 29 May 2019

Hello folks,

About a month ago, unrelated to any changes to the system or any new appliances in the house the consumer unit RCD (that covers the ring-mains, cooker and shower) tripped randomly while we were watching TV.

It then happened again later that week and once again just now (3 weeks later). Always seems to be in the evenings, but not at a regular time (first time it was around 5:30pm, second time was around 7pm, 3rd time was just now, 9:45pm).

It resets just fine each time.

Three times is enough to make me think there is something wrong. How do you go about diagnosing something like this?

Cheers.

JohnW2 · 29 May 2019

Seb101 said:
It then happened again later that week and once again just now (3 weeks later). Always seems to be in the evenings, but not at a regular time (first time it was around 5:30pm, second time was around 7pm, 3rd time was just now, 9:45pm).

Was the cooker (or shower) being used at the time. What things are plugged infto the 'ring main' concernbed, and were any of them running/working at the time?

Kind Regards, John

donrkebab · 29 May 2019

An electrician can test the tripping current of the RCD.

Seb101 · 29 May 2019

JohnW2 said:
Was the cooker (or shower) being used at the time. What things are plugged infto the 'ring main' concernbed, and were any of them running/working at the time?

Kind Regards, John

The ovens were switched on (standby) but not cooking. Same with the shower, on but not running.

I mean, there's a lot of stuff running on the ring main... fridge/freezer, tv, skybox, soundbar, modem, router, 3 lamps, couple of computers, couple of mobile phone chargers, printer, 3 amazon echos, pair of speakers.

Nothing high-current or anything that would be 'switching' during that time.

Not sure where to start.

Seb101 · 29 May 2019

donrkebab said:
An electrician can test the tripping current of the RCD.

Sure - but other than me forking out £50, what's that going to prove? Do RCDs 'degrade' over time? It's been fine for the last 5 years.

EFLImpudence · 29 May 2019

Well, it's going to prove the RCD is satisfactory - they usually 'degrade' by not working at all - and he can measure the earth leakage current on the circuit(s); it's the only way to find out.

If it is ok, then obviously it will be something else intermittent (a bugger to find).

The fridge/freezer may be leaking moisture on to the wiring. You could try first by plugging it into an extension lead from a socket not on that RCD.
Is there an outside socket that might be getting wet?

JohnW2 · 29 May 2019

Seb101 said:
Nothing high-current or anything that would be 'switching' during that time.

In addition to what EFLI has said about condensation, fridges and freezers do 'switch' on and off whilst running - which is probably another reason to try to rule that out as a possible cause.

Kind Regards, John

donrkebab · 29 May 2019

As a start try manually tripping the RCD a dozen times or more, this is called "exercising" and could loosen things up that have been sitting there doing nothing for 5 years.

JohnW2 · 30 May 2019

donrkebab said:
As a start try manually tripping the RCD a dozen times or more, this is called "exercising" and could loosen things up that have been sitting there doing nothing for 5 years.

That is sometimes appropriate, but it addresses a problem which is the opposite of what the OP is experiencing.

crystal ball · 30 May 2019

First place I would look is the shower and associated switches, seen many a burnt out connection causing trips

JohnW2 · 30 May 2019

donrkebab said:
.... I suppose you're now an expert in the construction details of every known RCD ever made.

Nope, any more than you are (or anyone else is).

However, what I do know is that the last thing one needs to do with an RCD which is tripping unexpectedly is to "loosen it up" - that is something one can try if an RCD appears to be 'sticking' and does not trip when it should.

EFLImpudence · 30 May 2019

Yes, exactly.

An RCD suspected of tripping too easily hardly needs to be 'exercised' to make it trip more easily.

EFLImpudence · 30 May 2019

donrkebab said:
You know well that my idea could work, you just want another argument, with lots of pointless questions.

No, we want some valid answers.

Did you not know that is the purpose of questions?

EFLImpudence · 30 May 2019

donrkebab said:
Who are you to make demands of me

I was asking, not demanding. I am eager to learn from your vast experience.

and who are "we", sounds like a little clique to me.

Everyone else who thinks you are giving wrong information to posters.

Did you not know that questions should not be answered by questions, and people should write more clearly.

Don't do it then.

We shall conclude that you don't know.

donrkebab · 30 May 2019

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Random RCD Tripping

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