Pole Lighting Circuit Tripping Breaker After Several Hours Of Operation

[Ravenvalor]

I have a customer who has about 10 - sidewalk pole lights that trips the breaker after several hours of being on. They have standard medium base sockets with 10-watt LED lamps in them. Is there a way to find the short quicker than the method that I use? I usually open up the circuit about halfway, turn the lights on and wait to see if the circuit trips, if it does then I close the circuit back up and halve it again towards the breaker, I just keep doing this until I find the problem. As you can see, my method is very slow and cumbersome. I was wondering if someone would not mind sharing with me a quicker alternative. Perhaps temporarily replace the 10-watt lamps with 150-watt lamps?

Thanks for the help.

 

[ptonsparky]

Use a megger and divide and conquer has you have been doing.

 

[Ravenvalor]

Use a megger and divide and conquer has you have been doing.

That sounds like fun. I’ll buy one today. Thanks

 

[hillbilly1]

Don’t forget to remove all of the lamps if you meg it like @ptonsparky suggested. If it is a defective lamp, do the divide and conquer by replacing only half at first. Still not going to speed up your troubleshooting though. I’m assuming this is not 277 volt?

 

[Dennis Alwon]

What else is on the circuit?

 

[Ravenvalor]

Don’t forget to remove all of the lamps if you meg it like @ptonsparky suggested. If it is a defective lamp, do the divide and conquer by replacing only half at first. Still not going to speed up your troubleshooting though. I’m assuming this is not 277 volt?

Thanks for the help.
It is 120-volts and there is nothing else on this circuit.

 

[hillbilly1]

Another thing to check if you haven’t already, is the buss connection on the breaker, if it is burnt, it could be heating the breaker enough to trip eventually.

 

[don_resqcapt19]

Have you checked the actual load? That sounds like a long time trip condition caused by the load or a poor connection at the breaker, or a fault with resistance high enough not to instantly trip. This could be a ground fault condition.
If this is the case, you can use an amp meter to help track down the fault. Current at the breaker, and then at the each light looking for a big drop in the amount of current.

 

[Ravenvalor]

Have you checked the actual load? That sounds like a long time trip condition caused by the load or a poor connection at the breaker, or a fault with resistance high enough not to instantly trip. This could be a ground fault condition.
If this is the case, you can use an amp meter to help track down the fault. Current at the breaker, and then at the each light looking for a big drop in the amount of current.

Thanks for the advice.

 

[WaveGuide]

What type of breaker is it? Have you replaced the breaker? Breakers go bad and sometimes start to misbehave. This sounds to me like an intermittant breaker.

Also have you visually and tight checked the connections, all of them?

 

[gar]

230410-1555 EDT

Ravenvalor:

You have a steady state load of about 1 A.

What is the size of your breaker?
If you measure the total input current to this string of lights, then what is the current after you first turn the lights on?
Then after the lights have been on for a while?
Does this current change much vs time?
What is the breaker manufacturer?

The current measurement should be made right at the breaker.

.

 

[Ravenvalor]

230410-1555 EDT

Ravenvalor:

You have a steady state load of about 1 A.

What is the size of your breaker?
If you measure the total input current to this string of lights, then what is the current after you first turn the lights on?
Then after the lights have been on for a while?
Does this current change much vs time?
What is the breaker manufacturer?

The current measurement should be made right at the breaker.

.

I will definitely make these tests.

Thank you