# Sorting a circuit to find a bad ballast?



## Trigger_442A (Sep 15, 2012)

I work in an industrial facility and worked with an electrician to find a short circuit on a 347 lighting circuit, suspected a ballast was tripping the 3 pole breaker and his idea was to turn the breaker on and watch for sparks!! I felt this to be a very unsafe method of troubleshooting and he argued this is how all the electricians he worked with do this method for finding the bad ballast 🚒. Am I wrong or is this the method that some of you may use or seen done before. I refused to find it this way as normally I would use an ohm meter on a dead circuit and trace this way.


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## nolabama (Oct 3, 2007)

Try his way first. How many lights are in the circuit? Take the circuit apart. Divide and conquer.


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## Big John (May 23, 2010)

I don't know whether it was intentional or not, but the fact that you somehow managed to put a tiny little firetruck icon smack in the middle of that story is awesome. :laughing:

In addition to being dangerous, closing breakers into a fault is an OSHA and NFPA violation.

Further, how often does something actually shoot sparks? Pretty unlikely way to find a fault.


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## Trigger_442A (Sep 15, 2012)

nolabama said:


> Try his way first. How many lights are in the circuit? Take the circuit apart. Divide and conquer.


 There are three or four 1000w hps on this circuit, but we were unable to look further as production must go on. I was just curious what methods others would take. I was taught never to trip a breaker on purpose especially on a 600v circuit!


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## Trigger_442A (Sep 15, 2012)

Big John said:


> I don't know whether it was intentional or not, but the fact that you somehow managed to put a tiny little firetruck icon smack in the middle of that story is awesome. :laughing:
> 
> In addition to being dangerous, closing breakers into a fault is an OSHA and NFPA violation.
> 
> Further, how often does something actually shoot sparks? Pretty unlikely way to find a fault.


Haha yeah the fire truck was intentional 🚒⚡I posted on my ipad so I can use emoji icons!! 

I agree that this would not be a way to find the fault but he was an electrician and I did not challenge his method I just chose not to be a part of it. 
Thanks


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## Celtic (Nov 19, 2007)

Trigger_442A said:


> There are three or four 1000w hps on this circuit, but we were unable to look further as production must go on. I was just curious what methods others would take. I was taught never to trip a breaker on purpose especially on a 600v circuit!


During the next scheduled outage...

Replace them all....bench test them, repair as needed, put on shelf until next time.
If possible, rewire to include an easy means of disconnect...like a plug and outlet.

Lather, rinse, repeat as needed.


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## Vintage Sounds (Oct 23, 2009)

1000w HPS?


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## Introyble (Jul 10, 2010)

Funny you used the words unsafe. Unsafe as in it's going to get somebody hurt? I have found problem ballasts buy flipping the breaker and watching for sparks.


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## Trigger_442A (Sep 15, 2012)

Introyble said:


> Funny you used the words unsafe. Unsafe as in it's going to get somebody hurt? I have found problem ballasts buy flipping the breaker and watching for sparks.


Yes unsafe, someone has to flip the breaker!


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## Southeast Power (Jan 18, 2009)

Sometimes you can look at an enclosed fixture with binoculars and find the bad one.
Works about half the time but, worth a try.


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## gnuuser (Jan 13, 2013)

in this instance having accurate maintenance records comes in very handy
on large lighting circuits when you have a ballast failing the bulbs tend to burn out sooner in the lights upstream of the failing unit.

but ive found that most industries rarely keep accurate records for lighting 

this is a divide and conquer type of hunt for your bad unit
also look for burn marks or heat distortion. and some ballast's emit a foul odor as well so your nose can help too


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## Trigger_442A (Sep 15, 2012)

gnuuser said:


> in this instance having accurate maintenance records comes in very handy
> on large lighting circuits when you have a ballast failing the bulbs tend to burn out sooner in the lights upstream of the failing unit.
> 
> but ive found that most industries rarely keep accurate records for lighting
> ...


We do not have a maintenance record of our lighting, and this is a great idea!! We have marked columns so it will be easy to start, thanks for the idea!!


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## Hefty (Oct 17, 2008)

*Meg test*

I work on lighting a lot and have found a megohmeter to be very useful. Divide the circuit in half and test each conductor to ground. If one half of the circuit fails, divide that section in half, test again and repeat until failed ballast or conductor is found. 

I frequently employ this method for parking lot lighting to find failed ballasts, underground breaks and damaged conductors in poles due to birds' nests. All without ever resetting the breaker until problem is corrected.


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## Zog (Apr 15, 2009)

Introyble said:


> I have found problem ballasts buy flipping the breaker and watching for sparks.


MCCB's are typically designed to interupt 2 faults near max AIC rating per UL 489, you really think that is the best way to troubleshoot?


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## brian john (Mar 11, 2007)

If the distribution system had GFPE you could dump the site or a portion of it.


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## Jlarson (Jun 28, 2009)

The surefire method is to temp the lighting circuit directly to the load side of the facilities main then flip it on. The area of flaming rubble was the bad fixture. :laughing:


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## macmikeman (Jan 23, 2007)

I used to stick inline fuseholders into strings of lights in office buildings. Then it was as easy as finding the one that didn't light up.


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## cdnelectrician (Mar 14, 2008)

brian john said:


> If the distribution system had GFPE you could dump the site or a portion of it.


I have seen this happen before. Not to mention the branch breaker could blow up in your face.


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## Introyble (Jul 10, 2010)

Zog said:


> MCCB's are typically designed to interupt 2 faults near max AIC rating per UL 489, you really think that is the best way to troubleshoot?


My daddy once told me if I wanted to learn the easiest way to do something, just watch a fat man do it


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## bobelectric (Feb 24, 2007)

Spark test one time, then open up and do the sniff test.


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