Quick question on light install

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Old 09-10-16, 06:23 PM
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Quick question on light install

Hi folks,

I'm replacing a light fixture that is installed on the wall above the bathroom vanity. There's a light switch next to the vanity that works the lights, and there's also a GFCI outlet next to it. Three quick questions that are probably very easy for you guys:

1. The outlet box in the wall is a rectangular, blue, "old work" box. I'm used to seeing the octagonal metal boxes for light fixtures that has a ground screw. Is it ok to use the existing box?

2. Since there is no ground screw on the plastic outlet box, I took the bare wire from the light, wrapped it around the green screw on the light's cross bar, and then attached it to the house's bare wire with a wire nut. Is that right?

3. The wires coming into the outlet box have black, white, bare, and red. The black, white, and bare are used, but the red one is just snipped off. Is that ok? I don't know what the red wire is for.

Please see my attached very crude diagram.

Here is a link to the install directions just in case it helps.

Thanks!
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Old 09-10-16, 06:34 PM
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A standard blue plastic box is fine for a fixture. If it's a particularly heavy fixture you may need to mount the lighting back box in several places.

Your wiring is fine. The extra red wire would be used if the fixture had multiple lamps and you wanted to switch them separately or they only had three wire cable left when they did the installation. Put a wire nut on it and stick it in the back of the box.
 
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Old 09-10-16, 07:34 PM
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Thanks for the quick reply. I finished the wiring and the light turned on just fine. I turned on the light switch about seven or eight times, and the GFCI tripped. I reset the GFCI and tried again and after about 10 flicks of the switch, the GFCI tripped again. This time the GFCI would not reset, so I checked the GFCI in the master bathroom across the hall and it was also tripped. When I reset it, then I was able to reset the one in the bathroom I was working in. Does this sound OK to you, or is the GFCI just not happy because I was flicking the switch on and off? I wasn't going obnoxiously fast, but I was flicking it at a steady pace.
 
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Old 09-10-16, 08:08 PM
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The GFI doesn't care how many times you flick the switch. It detects an imbalance between hot and neutral.

That should not be happening in that application. Are those standard incandescent bulbs ?
 
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Old 09-10-16, 09:26 PM
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I just have 3 led bulbs in there. They are 60-watt equivalent each. I also put one of those testers in the outlet to make sure it's wired correctly, and it showed no problems.
 
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Old 09-10-16, 09:36 PM
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Ok.... the spike caused by the ballasts in the LED bulb could cause a trip issue.
Since you won't be randomly flipping the switch the GFI shouldn't trip.
 
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Old 09-10-16, 10:38 PM
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Ok, my novice brain doesn't quite understand what that means, but I'll take your word for it. :-) But overall you think it's ok as-is?
 
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Old 09-10-16, 11:35 PM
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The LED's run on low voltage so there is a power supply built in to them to drop the voltage from 120v to something usable. That circuit creates a spike on the AC line. It's normal.
Flipping the lights on and off continuously causes that spike to build up to the point where it trips the GFI.

If there was a problem with the fixture it would trip the GFI every time you turned the lights on.
 
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Old 09-11-16, 12:33 AM
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The light should be on the line side. Do you have it on the load side instead?
 
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Old 09-11-16, 01:55 AM
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You do not need both gfi's. Regular receptacles can be wired if wired from the load terminals of the upstream gfi. Or you can wire both using just the line terminals.
 
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Old 09-11-16, 06:38 AM
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Ok thanks for the help guys, really appreciate it!
 
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