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I'm replacing conventional lights with Model CLL56-2WW LED fixtures and all went well on first 3 installs.

The 4th is wired just like the rest- white to white, black to black, ground to ground and works fine when the light is unmounted (hanging from wires).

However, when I connected it to the box, the Cbreaker tripped- I imagined I had somehow damaged or inverted a wire, however when I dropped the fixture all looked well and the light worked after the circuit breaker reset.

So I imagined that maybe a surge had taken place and tried the whole thing over again- This time there was a spark at the screw that connects the light base to the box before the breaker flipped. Light still works fine when unattached to box.

So I stopped and can't imagine what is going on-

I was thinking that since this is an old house, maybe black and white are reversed- However, if this was true, why didn't the previous fixture short and why did the other new installs work?

I do have a nice LCR multi-meter and I would really appreciate any thoughts to diagnose and fix!

Thanks in advance!

Adding photos: enter image description here enter image description here Note scorch mark at bolt hole

Also note that image 2 is much simpler than it looks- The black wire is wrapped around white wire near white wire nut (from being pushed up into box) and then runs behind the ground nut. He should have pulled down more and they would have pulled away from each other for a clearer photo- all 3 wires are totally independent and appear to be in good condition.

And note singe mark in photo 3 where bolt sparked.

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  • It's my bro in laws house and was hoping to fix this the next time I visit;) However, very easy to imagine- Junction box is recessed in ceiling- has 2 screws that hold the light bracket- 2 more screws decend from bracket and twist and tighten onto the new fixture. As expected, all 3 wires assend from the back of the new fixture and are wire nutted and taped to like colors. The sparking occurred at one of the 2 bolts that assend thru the light base and into the supporting strap.
    – Votemickey
    Dec 20, 2017 at 17:12
  • Ok, he will send me photos when he gets off work- much thanks!
    – Votemickey
    Dec 20, 2017 at 17:53
  • Bro in law came home to take photos embedded in thread
    – Votemickey
    Dec 20, 2017 at 18:56
  • Disconnect the fixture and inspect the wires then turn on the circuit and the switch without the light. If it trips the breaker it is the wiring. Otherwise the fixture is the problem.
    – ArchonOSX
    Dec 20, 2017 at 18:57
  • ArchonOSX, I can try that, but considering the light works fine when the fixture isnt connected to the box, doesn't that proved the wiring isn't faulty?
    – Votemickey
    Dec 20, 2017 at 20:13

1 Answer 1

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In this picture the black wire looks damaged right as it comes out of the fixture. In other pictures you can clearly see that one of the mounting screw holes has electrical burn marks on it.

Because of the scorching, we know that one way or another, the hot side of the circuit found a path to ground through the fixture. This is either because the wire going into the fixture is damaged, or something else is wrong. If it was internal to the fixture, the ground wire should be causing the breaker to trip immediately, so I'm still thinking it's a damaged wire.

Warning - if the fixture trips the breaker when it's installed in the box, that means the entire fixture could be electrified when it's turned on. Don't even touch the fixture when it's turned on. I would make sure the breaker, not just the switch, is turned off before touching anything at all.

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  • Wow, good eye JPhi- I had focused on house wire- never imagined the new fixture wire may be the culpret- Can't wait to look it over and see if the break that you are seeing is real or just a bad photo-
    – Votemickey
    Dec 20, 2017 at 20:20
  • Also thanks for reminder that fixture could be live
    – Votemickey
    Dec 20, 2017 at 20:21
  • That part of the light where the wire comes out will press against that bracket in the box. Seems like that bracket should be installed so the hump goes inside the box so it doesn't contact the fixture.
    – JPhi1618
    Dec 20, 2017 at 20:27
  • Makes sense - big, big thanks and I'll let you know how things go
    – Votemickey
    Dec 20, 2017 at 21:14
  • You should pull down the other lights too and turn that bracket over - they may be damaging the wires too.
    – Mark
    Dec 20, 2017 at 23:17

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