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Electrical

flourescent lights

I have built a garage and I want to put in  fluorescent lights in it. I want to install 8 lights with 2 @ 40 watt bulbs. Will a 20 amp breaker handle these lights?  They are the only thing on this circuit.
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Posted 2019-04-24T00:59:57+0000  by brucea brucea
 
8 two lamp fluorescent fixtures fine on a 20 amp circuit.  If you plan on using your garage as a shop it's always a good idea to keep the lights on a different circuit than the tools.  If you happen to trip a breaker using a tool, it's not a lot of fun to stand in the dark as a saw spins down.
Posted 2019-04-24T11:57:37+0000  by Adam444

Hi They are on their own separate circuit.  With a 20 AMP breaker.

But when I turn them on, all of the lights light up, but the last one shuts down. It stays on for the than 1 second. I have around 13 feet of wire from the breaker box to the light switch. And then it is another 112 feet from the switch to the last light. I have used 12 ga. electrical wire all the way. But I am not sure why the last one does not stay on. Can you give me any ideas how to fix this problem.

Thanks

Posted 2019-04-25T01:54:53+0000  by brucea

Hi They are on their own separate circuit.  With a 20 AMP breaker.

But when I turn them on, all of the lights light up, but the last one shuts down. It stays on for the than 1 second. I have around 13 feet of wire from the breaker box to the light switch. And then it is another 112 feet from the switch to the last light. I have used 12 ga. electrical wire all the way. But I am not sure why the last one does not stay on. Can you give me any ideas how to fix this problem.

Thanks

Posted 2019-04-25T01:54:54+0000  by brucea
At a 125 feet you do have worry about voltage drop but it shouldn't be significant enough to cause the fixture not to light.  Is the fixture new?  It could just be a bad ballast.  Try hooking it up closer and see if the problem goes away.  If not replace the fixture.

I would also change the breaker from 20 amps to 15.  At 125 ft. you have about 5% voltage drop (3% is recommended).
Posted 2019-04-25T11:44:39+0000  by Adam444

Hi


Yes the light is new, right out of the box.


I will try it in a different location.


If I have the same problem there, I will know its a bad light.


Thanks for the advice.

Posted 2019-04-26T03:02:11+0000  by brucea
Hello brucea.  Welcome to the Community!

8 Fixtures pulling 80 watts each equals a 640 watt load.  At 120 volts this will be less than 6 amps.  Even with a 125 foot circuit you will have less than 2% voltage drop using 12 gauge copper, and this assumes the entire load is at the end which it is not.  I think the issue you have is with that last fixture.  Either it has a bad ballast, tubes or connection.

Changing the breaker down to a 15 amp one would be convention for lighting circuits.  It is not necessary if all your wiring is 12 gauge.  I doubt you will notice the difference, as the load you put on this circuit will not trip either one.

Chris.

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Posted 2019-04-26T16:35:08+0000  by Chris_HD_CHI
Chris, 

With all due respect, you might want to do a little reading on how a branch circuit is sized.  It's NOT the anticipated load but rather the possible load.  
Posted 2019-04-30T10:54:00+0000  by Adam444
 
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