# Lighting contactor circuit fault



## bhad (Jun 5, 2015)

Trouble shooting an isle lighting fault in a department store. There's a Square D panel with a lighting contactor at the bottom of the bus which is remotely controlled, turns on and off the isle's lighting at the start and finish of the work day.
The 1P20A c/brkr will trip off when the contactor is turned on at 8 am, when reset it will stay on all day and is only drawing 5 Amps.
l removed half the lighting load - still tripped, replaced c/brkr and put circuit onto another phase, if it still trips, I'll remove all the lights off that circuit, if no go, then I'll isolate it at the last junction box where all the other circuits split off...
I thought it might be in-rush current when the lights all turn on at the same time.
Any other suggestions?


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## bhad (Jun 5, 2015)

What about connecting a power analyzer on that circuit to see what it's doing at switch on?


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## Moonshot180 (Apr 1, 2012)

Are there any other similar breakers in the panel you could swap with? That would tell you if the breaker needs to be replaced.

Not much else you can attribute it to that I can think of.. especially if the circuit load is within the rating of the breaker.

Just for clarification, the contactor controls the entire lighting panel correct?


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## telsa (May 22, 2015)

Moonshot180 said:


> Are there any other similar breakers in the panel you could swap with? That would tell you if the breaker needs to be replaced.
> 
> Not much else you can attribute it to that I can think of.. especially if the circuit load is within the rating of the breaker.
> 
> Just for clarification, the contactor controls the entire lighting panel correct?


Square D make a 'smart' C/B that integrates a contactor triggered by a LV signal with _each_ C/B. 

These, then, are very slim, but longish, assemblies. They are usually found as factory assemblies -- complete. They are to be tied into BAS that can be linked to the national HQ of a major retailer.

Toys R Us uses Squared D unified assemblies. These come to the site wholly built at the factory.

Safeway and other grocers have adopted them, too. 

They can over-ride the locals from national HQ.

I would strongly suspect that such might be the issue here. You can have two glitches. 

1)The common vanilla C/B and circuit issues -- and 

2) The LV contactor -- and the folks programming it back at HQ. 

I've never seen one misbehave, but every device can go sour.

You might find that the glitch is initiated back at HQ... though that'd be my last suspect.

I would assume that the circuit in question is NOT popping when landed on a conventional Square D 1p 20A C/B.

OP, you ARE dealing with 'smart' breakers, are you not ?

http://www.homedepot.com/p/Square-D...wer-Link-Circuit-Breaker-QO120PLILC/204176782

homedepot.com/p/Square-D-QO-20-Amp-0-7-in-Single-Pole-ILC-Power-Link-Circuit-Breaker-QO120PLILC

Power Link Circuit Breaker QO120 ILC ( in-line contactor ? )

http://www2.schneider-electric.com/...ive/FAQS/228000/FA228072/en_US/1210CT0201.pdf

Robust 24Vdc motor and highly effective trip mechanism provide unequaled
remote operation capability in terms of compact size, electrical ratings, and
mechanical life.

• Motor and drive train can open and close the contacts when the circuit
breaker handle is in the ON position.

• Contacts cannot be closed remotely when the handle is in the OFF position
or the circuit breaker is tripped.

• *Manual override selector located on the front of the circuit breaker –
extremely useful when manual lighting control is critical or when a loss of
control features occurs.*

This is you. ^^^^


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## bhad (Jun 5, 2015)

Just for clarification, the contactor controls the entire lighting panel correct?[/QUOTE]

Yes, the contactor controls the whole panel.
I put the misbehaving circuit on a new cbrkr and on another phase and it is now working correctly, we are going to monitor it for a week and if no glitches then I'll close the case.
Thank you all for your helpful advice.:thumbup:


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## billn (Aug 31, 2011)

Well, you will know that the breaker was probably faulty. It is unlikely that moving it to a different phase made any difference.


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## ELECTRICK2 (Feb 21, 2015)

billn said:


> Well, you will know that the breaker was probably faulty. It is unlikely that moving it to a different phase made any difference.


Agree with billn, bad breaker. Next time you have intermittent tripping try this. If you have 2 circuits doing the same thing (5A of lights) one trips and one doesn't, swap the 2 hots. Same breaker trips, it's the breaker. Other breaker trips, it's in the circuit.


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## billn (Aug 31, 2011)

Yep. When troubleshooting a circuit, only change ONE thing at a time.


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