Lights keep tripping...

[Newbie90]

Hi all

Has anyone got any ideas why a lighting circuit would randomly trip the mcb?

The maximum Zs tested was 1.07 ohms.

Its only ever happened (3 or 4 times) when the 2 wall lights in the front room are switched on. They both have energy saving light bulbs and none of them ever blow.

It doesn't trip the rcd, just the mcb.

Thanks

 

[bigbaddave]

I dont agree with that squire, it doesnt mean it's wrong because the circuits 20 yrs old and he's getting 299.

I dont see the issue myself with the result, he was testing a single circuit.

I agree with that to a point. However A) Still 299m is high on 1.0/1.5 20 years old install but ill agree not impossible b) the OP clearly states that the tv booster is installed in the loft which from the first few posts I beg to differ that this has been removed this connected would defiantly make the 299m inaccurate. C) something is making the MCB to trip he has already highlighted that is not overload. Other than Faulty MCB id be a bit wary if the IR were so high on the offending curcuit.

Provinging that they are correct then id be checking anything removed in order to conduct the IR test

 

[Newbie90]

The main issue is that he is getting >299 and there is supposedly a TV amp hard wired into the circuit which has not been removed.

It was tested with the tv amp removed and was fine.

As posted by another member, the circuit was tested individually which is what I always do. I have witnessed a lot bigger and older circuits being tested for IR and it was also >299.