Led street lights tripping mcb

[cliffed]

Just had a quick look at a job,intermittent tripping of 10 amp mcb,retrofit led replacing discharge lighting,some time ago.
There are 7 street lights,couldn’t real do too much investigation,rain stopped play.
Did a IR test proved to be satisfactory,just wondering if any of you guys
Had any thoughts.

 

[Marvo]

Try get more info off the customer about whether the tripping is immediate as the lights come on. It could be inrush current but usually that would be a problem from day one. I'd do all the usual dead tests and visually inspect all lights on the circuit for signs of terminations overheating/burning, also insect infestations, signs of water ingress etc before replacing the MCB with a slower curve alternative.

 

[cliffed]

Thanks everyone,off to see what I can do.

 

[DPG]

Wonder what's causing the 2.5M IR? What was that measured between?

 

[freddo]

2.5M is not a terrible reading, certainly not for a load of o/s lights. Very small amount leakage current.

 

[DPG]

2.5M is not a terrible reading, certainly not for a load of o/s lights. Very small amount leakage current.

I agree, not terrible. But also not great.

 

[cliffed]

Yea I think the IR ok.
Been back & think I’ve sorted it,Zs measures 1.37 ohms,so okay.
After testing,switching on off,the mcb tripped,tried on the other lights,which are exactly the same,this did not happen.
Swapped 10 amp for C type,that worked without tripping,monitoring over next couple of weeks.

 

[Nigel]

Posts like this besume me.

In all honesty it could be absolutely anything. There is no limit to the number of ideas that can be posted that would all be relevant.

It is impossible to fault find over the internet. You need to go back and test until you find the issue. Being intermittent it may just be a case of replacing the MCB as a start but u less you are prepared to try all the 100 possibilities floated on here it is pretty pointless asking.

 

[cliffed]

Like I’ve said,it’s an on going situation,the IR results are fine,I’ve changed the mcb,tested the system.
I’m not asking for anyone to find the fault for me,interested in what fellow electricians think.
The client been informed of all the tests,& we will see if a fault situation re occurs.

 

[Octopus]

Posts like this bemuse me.

In all honesty it could be absolutely anything. There is no limit to the number of ideas that can be posted that would all be relevant.

It is impossible to fault find over the internet. You need to go back and test until you find the issue. Being intermittent it may just be a case of replacing the MCB as a start but u less you are prepared to try all the 100 possibilities floated on here it is pretty pointless asking.

I've given you a disagree, because we all know that start up currents can be very high on LED's and as the reported IR wasn't low, swapping the MCB for a type C makes perfectly good sense

 

[cliffed]

Agree..
Hopefully it’s solved the prob.