Whats the fault :)

[axel132132]

As you all know my electrical knowledge is not great, my fault finding is also not great. So please Dont abuse im only asking so i have more knowledge to my customer - I know exactly how to test, wire and all that just thought id ask this get a more clear idea

SO

Phone call from local pub, "dave my lights keep blowing!" i go down, the lights are on.. He has a GRID switch with about 20 light switches on, as soon as he presses Outside Lights BOOM breaker trips.. NOW going through my head is obv there a short in one of lights or something..

Few questions, first he said its been doing this a while now but before he was able to switch the breaker back on in the board and all the lights would come back on. (<-- this be what confusing me).. Could this possibly be a broken breaker and not a short?

Im thinking maybe overload has broken the breaker as the breaker is a 6A breaker.. But yet has all the pub lights on downstairs, and also all the external lights.. There are about 10-15 SON light fittings outside and 2-3 Sign Lights and then a socket that has all the fairy lights plugged into it!

Also next question why would the breaker trip and not the RCD? As the circuit is RCD protected (Again this will help my knowledge and able me to learn so would be greatfull cheers)

 

[bigbaddave]

If it s not trpping the rcd then sounds like overload. Whats the total load on the curcuit ?

I had the same issue once before, Too many lights on a lighting circuit and when testing was pulling 11 amp. Trips breaker due to overload.

 

[markc123]

As you all know my electrical knowledge is not great, my fault finding is also not great. So please Dont abuse im only asking so i have more knowledge to my customer - I know exactly how to test, wire and all that just thought id ask this get a more clear idea

SO

Phone call from local pub, "dave my lights keep blowing!" i go down, the lights are on.. He has a GRID switch with about 20 light switches on, as soon as he presses Outside Lights BOOM breaker trips.. NOW going through my head is obv there a short in one of lights or something..

Im thinking maybe overload has broken the breaker as the breaker is a 6A breaker.. But yet has all the pub lights on downstairs, and also all the external lights.. There are about 10-15 SON light fittings outside and 2-3 Sign Lights and then a socket that has all the fairy lights plugged into it!

Few questions, first he said its been doing this a while now but before he was able to switch the breaker back on in the board and all the lights would come back on. (<-- this be what confusing me).. Could this possibly be a broken breaker and not a short?

Also next question why would the breaker trip and not the RCD? As the circuit is RCD protected (Again this will help my knowledge and able me to learn so would be greatfull cheers)

... Water in the outside fitting.

RCD will not trip unless leakage to the earth.

 

[axel132132]

I didn't have time to check the load or anything, i was just quickly passing and thought maybe he had a tripped breaker or something as he just said my outside lights Dont work

 

[bigbaddave]

... Water in the outside fitting.

RCD will not trip unless leakage to the earth.

Dope.. Outside lights.. Yes as above this would show as low readings on IR bud..

The dope is me btw not reading the full post.

 

[axel132132]

God damn it! Ha thanks guys guess i was just being hopeful that it was just the breaker ><! Now gonna have to check each fitting..

Wise idea to start with the fittings with the lamps blown??

 

[Silly Sausage]

Axel, have you signed your soul away to National Grid yet?

 

[bigbaddave]

I didn't have time to check the load or anything, i was just quickly passing and thought maybe he had a tripped breaker or something as he just said my outside lights Dont work

I see I see. If the guy is saying that its only the outside lights causing the breaker to trip then id be doing a IR test (Unfortuanlty though its a L-N needed so taking lamps out is a must) and then if thats a bad reading narrow it down with the switches to bring lights into the curcuit. If its not just the outside lights id be checking the full load being pulled

 

[axel132132]

Yeh, ill try that i could do IR on 230?

As for the taking lamps out etc and doing all that the customer isnt getting much trade so is very poor Ha.. and as everyone knows pubs are shutting down all the time and he wants to stay up so telling me he cant afford my hourly rate even though i was only charging him £15 / hour to do it so was going to do it to him as a favour as most my work has come from his recommendations thats why im trying to narrow it down as much as possible ;D!

What happens is the Breaker powers the GRID, the GRID lights up all the pub lights internal and external but one switch on the GRID says "Outside Lights" he can turn all other lights on but as soon as he presses this it trips breaker!

 

[telectrix]

i have had a case where the L conductor was chafed in an outside galv. box. intermittently short to the box. that tripped the breaker rather than the RCD, although the RCD did trip some of the time. before condemming the outside lights, though, try switching the outside lights on first, then if it holds, then switch on the indide lights 12 at a time. be a good idea to clamp the circuit at the MCB while you are doing this. if it trips when you are turning on the lastlight/s, then it could be overload or a dodgy breaker, depending on your clamp meter reading.

edit: asa the RCD has not tripped, it could still be an earth fault coupled with a fauly RCD, so test the RCD as well.

 

[axel132132]

Axel, have you signed your soul away to National Grid yet?

Lol not yet mate, i have to apply online at end of FEB ive just been guaranteed to the final interview

 

[Silly Sausage]

Lol not yet mate, i have to apply online at end of FEB ive just been guaranteed to the final interview

Progress then! :icon14::shades_smile:

 

[telectrix]

good luck with it.

 

[Octopus]

Mate. Fault finding is about listening to what the customer says then using your knowledge to understand what is actually going on.

I'd be going to the pub when its closed and working from there.......

First step is does the MCB go when just the o/s lights are on...

 

[Engineer54]

Few questions, first he said its been doing this a while now but before he was able to switch the breaker back on in the board and all the lights would come back on. (<-- this be what confusing me)..

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If ALL the lighting on that circuit is affected and the breaker doesn't trip then it has to be a circuit conductor, probably one that's loose and at or towards the origin of the circuit!! Breakers don't trip and come back on their own. ...Unless someone else switched the breaker back on without the OP or landlord knowing?? lol!!