Sign light trips on start-up.

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Saywatt

Member
Having an issue with a sign that is 40' in the air that occasionally trips the 20a breaker, but only at start-up.

It's controlled by a mechanical timer and each time I was called out the clock was stopped right in the middle of the "on" pin. This is intermittent and it has ran through several cycles between trips.

Everything looks fine, and the timer and breaker are new.
I've megged between l-g and n-g, even through the time clock, and it's testing ok. The sign company was suppose to have replaced the ballasts and bulbs.

I believe the sign consists of 3 magnetic ballast powering four 8' t12ho's apiece. When the sign is lit I'm reading around 11a.

Is it possible that there is inrush current that is too high for a single 20a breaker? Should they have dropped 2 lines down the pole for two 20a circuits?

Thanks.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Maybe the ballast are poor power factor and that coupled with the inrush is just enough to trip occasionaly. You could try a high magnetic breaker. If square D it would be a QO120HM or HOM120HM. I think must of the companies make a version. Just a thought as it is a cheap solution to try.
 

maghazadeh

Senior Member
Location
Campbell CA
Having an issue with a sign that is 40' in the air that occasionally trips the 20a breaker, but only at start-up.

It's controlled by a mechanical timer and each time I was called out the clock was stopped right in the middle of the "on" pin. This is intermittent and it has ran through several cycles between trips.

Everything looks fine, and the timer and breaker are new.
I've megged between l-g and n-g, even through the time clock, and it's testing ok. The sign company was suppose to have replaced the ballasts and bulbs.
I believe the sign consists of 3 magnetic ballast powering four 8' t12ho's apiece. When the sign is lit I'm reading around 11a.

Is it possible that there is inrush current that is too high for a single 20a breaker? Should they have dropped 2 lines down the pole for two 20a circuits?

Thanks.

texie
Maybe the ballast are poor power factor and that coupled with the inrush is just enough to trip occasionaly. You could try a high magnetic breaker. If square D it would be a QO120HM or HOM120HM. I think must of the companies make a version. Just a thought as it is a cheap solution to try.

Other option to consider;
1) If sign contractor has not replace ballast + lamps yet. Have them to retrofit it with LED. Or
2) When sign contractor shows up. you can use their left to drop another circuit.
 
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