Wall socket circui tripping off seemingly randomly.

[Rjrose]

ok lets get the basics out of the way..

do you have an immersion heater?

is it on a timer?
is it perhaps wired into the socket circuit?

do you have under floor/tile heating in the bathroom etc?

you mention oil.. does the tank have trace heating to keep the oil at a useable temperature?

1) Yes, but it is switched off and hasn't been used for a few years, so not on a timer. I'm not 100% certain which circuit its on and can't check due to time now, will edit in the morning.

2) No underfloor heating anywhere in our bungalow, a radiator (or two) in each room bar the kitchen.

3) No, just a plain garden oil tank no trace heating or gadgets.

 

[Rjrose]

Update: tripped again 9:09pm tonight, nothing was turning or being switched on/off at all.

Still no idea what it is causing it.

I suppose best option is contact another electrican to test it all, not the company who did the work but a second opinion?

 

[too old to learn]

you my have a loose conenction somewhere on the circuit.
If you can trace what sockets etc is on that circuit (turn the MCB off and see what does not work) and then check for tightness on all connections (I would still check for voltage each time for safety), hopefully this could solve the problem?

 

[securespark]

Best advice is to get the circuit tested for insulation resistance.

Are you certain that the device that is tripping is an MCB, not an RCD?

Can you post a piccy?

 

[Rjrose]

Pics:

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• Rjrose
• 20 Apr 2010
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• Rjrose
• 20 Apr 2010
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• Rjrose
• 20 Apr 2010
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[wingcoax]

You do not have an RCD so tripping fault must be on the circuit that trips.
You need to get the firm back to do insuloatio and resistance tests.

 

[Rjrose]

Thank you.

It would definately be a fault in the circuit?

I'm trying to rule causes out, the load on the circuit is variable but it does not trip more if - for example - all 3 of our PC's are on any more than when they aren't.

We originally wondered if the trips were caused by a dodgy wall socket - unplugging everything from a new socket in our kitchen stopped the nightly trips twice now, but then after a month it tripped again with nothing plugged into that particular "problem" socket.

 

[slup]

You do not have an RCD so tripping fault must be on the circuit that trips.
You need to get the firm back to do insuloatio and resistance tests.

Both the ring main breakers are RCBO's

 

[Electrifying]

Hi mate,

Your socket circuits are both on RCBOs (RCDs).
These monitor the circuit for earth leakage and only need a tiny amount of current to leak in order to trip them - approx 0.025 amps to 0.03 amps)

I'll bet good money that you have a neutral - earth fault on one of these circuits.

Without going into details, neutral/earth faults are load-dependant and so tripping of the RCBO can appear to be intermittent.
In some circumstances, the tripping can be caused by loads on other circuits - even with nothing plugged in on your socket circuit.

You need to get a spark who knows how to test properly - get him to do full ring-final continuity tests and IR test....L-N, L-E & N-E.

If he knows what he's doing, he'll find the fault.

 

[LoveRocket]

It would help if you told us which item in your CU is tripping!
Is it the one marked "RCBO C32"?

If so then Electrifying is spot-on. N-E fault somewhere...

 

[Rjrose]

Yes, correct it is RCBO C32 (circuit with most of our wall sockets on it).

Thank you and I'll see if we can get it tested properly as suggested.

 

[ban-all-sheds]

C32

Does your supply head have a notice (or can anybody here tell) saying anything about TN-C-S, or PME (Protective Multiple Earthing)?

 

[Rjrose]

No, not that I can see.

 

[LoveRocket]

C32

Does your supply head have a notice (or can anybody here tell) saying anything about TN-C-S, or PME (Protective Multiple Earthing)?

Whilst a C curve is unusual for a domestic final circuit, I don't see what bearing the earthing arrangement has on it.

 

[ban-all-sheds]

A C32 needs a maximum measured EFLI of 0.58Ω to meet disconnection times.

TN-S Ze is.....?