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]

20 years old and 299++ try testing again bud as your not doing somthing right.. And not nessessarly everytime bud.depends on your reading

But as said before what is the total load on the curcuit? Dont rule this out

 

[Newbie90]

Why would that mean its incorrect? I have personally seen test results and witnessed contractors testing my place of work which is over 20 Years old and they had insulation resistance readings as good as that.

The total wattage is under 500w so 6 amps is easily capable.

Loose connection possibly, faulty lamp holder? Possibilities?

 

[bigbaddave]

Retest IR bud.. Otherwise faulty MCB. Personally I doubt your IR figures. As 500w is not overloaded

 

[bigbaddave]

........

 

[Elmer BeFuddled]

Installation is probably 20 years old but cable runs are very short as its a small flat.

The same one as in your CU thread?

Therefore I am not as good domestically as most people on the forum but I doubt many people would be as good as me at my job.

I doubt very much that you could even begin to understand my old trade. But don't get me wrong, I'm an old newbie to this. But messing with electrics in flats that your father is renting out for gain, without proper certification etc. is a potential (for the tenant) life removing situation and (for you) a heavy court case.

I've been in your situation. Rebuilt my kitchen, moved cookers etc. Does your Dad get GasSafe folks in for any gas work but just plays with electrics as it only (usually) kills one person at a time. Not take the whole street out???

Can I ask a few questions, as you are in Cornwall. One of my favourite UK holiday spots.
Where are these flats based?
Are they holiday lets?
A link so I can avoid booking a holiday in one?

 

[Brightspark2]

20 years old and 299++ try testing again bud as your not doing somthing right.. And not nessessarly everytime bud.depends on your reading

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.

 

[Heisenberg]

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.

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.

 

[Elmer BeFuddled]

Aww shucks!! :blush5: I'm touched by the likes on my post #35!

I know my limits though and won't go beyond them. I've had nought to do since Xmas but had two calls this week. Turned them both down and passed on phone numbers of folks who would be more suited/experienced/qualified than me.
Just hope they drop a tanner in me hat and buy us a pint when I've sown me shoes back together.

(shuffles into the distance with a knapsack on me back ).

 

[MDJ]

Yeah run with the likes before any critism comes your way haha

 

[Elmer BeFuddled]

Yeah run with the likes before any criticism comes your way haha

I've been married 3 times. Criticism is like water off a ducks back!!


(And I'm still back for more!!)

 

[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.