MK RCBO tripping

[xd400]

Hi Everyone,

I'm helping out an elderly relative where this RCBO keeps tripping. It's a MK 7932s

Regardless of whether all items it supplies are on or off it will either stay on for about 5 mins and then trip...or just trip immediately. So I'm assuming it's a fault with the RCBO itself?

I've checked for issues at switches, water ingress at light fittings etc.

Also, nothing new has been fitted recently to cause this.

Can anyone enlighten?

 

[flameport]

So I'm assuming it's a fault with the RCBO itself?

Not impossible, but very unlikely.

Regardless of whether all items it supplies are on or off

Are these items being unplugged and totally disconnected from the circuit, or just turned off at a switch?

 

[fluorescence]

There's a large list of things it could be, not necessarily just something plugged in. Usual suspects would be an outside light that's fed off that circuit and is suffering moisture ingress, or cables damaged by mice or similar.

 

[Taylortwocities]

If you look back at similar threads about RCDs and RCBOs tripping, the first thought if the inexperienced poster is that the device is faulty. This is rarely the case.
There is most likely a fault with an appliance or the wiring itself. It’s a Sherlock Holmes task to discover the cause. Just switching things off isn’t enough to isolate something. Both the live and neutral needs to be disconnected.
If it takes a period before the trip after power has been restored, in my experience that smells like damp/ water in something.
This sort of thing can eventually be found by trial and error, but it’s not a precise science. The best way is to get an electrician to determine the problem.

 

[John D v2.0]

If it's an rcbo it could always be tripping due to overload, if you turn all ther circuits off the meet should stop. If you turn that one circuit on with all appliances off is the meter moving?
There was a similar issue on a lighting circuit and it turned out a concealed transformer was taking rather a lot of power.

 

[xd400]

Thanks all. Just to clarify, yes I'm only turning switches off, not isolating them completely. I will check one by one. BTW I am competent in electrical safety but if it is anything to do with the consumer unit I will leave it to a qualified electrician.