0

I have this three wire LED motion sensing outdoor fixture (labeled grnd, Neutral, Black) Outdoor light bracket

And I’d like to wire it to my current junction box which has only two wires, red (!!!) and white. Is this possible? It’s replacing my old fixture which actually was a three wire incandescent, which just used two:

Old fixture, black here actually feeds into red outside

Is this doable? The garage actually has three wire wiring, just this box doesn’t. I could do the old college try (it’s cheap enough that if i fry it i won’t cry) but i want to do the right thing.

EDIT the junction box. Notice there’s a bolt hole labeled GRD. I have no idea if it’s actually Ground junction box, with GRD Labeled bolt hole

10
  • Please include a picture of the open junction box where the old motion detector was attached to and wired into. – P2000 May 20 at 22:52
  • Can you post photos that show the inside of the junction box in question please? – ThreePhaseEel May 20 at 23:06
  • @ThreePhaseEel question edited to add junction box. – Rich Homolka May 21 at 15:46
  • What country / region ? – P2000 May 21 at 16:57
  • 1
    @ThreePhaseEel the back side is exposed in the garage it’s run in conduit – Rich Homolka May 22 at 1:09
1

What you show in pic 2 is the fixture. Looks like black and white are wired to the outlet box. (Red is the switched feed from detector to lights).

If there is a bare copper wire in your junction box, it should be connected to the green wired terminal.

Please include a picture of the junction box in your question. Then we'll know for sure.

2
  • Added pic of junction box. Thanks! – Rich Homolka May 21 at 15:47
  • @RichHomolka ok great, I'll let ThreephaseEel comment on the code specifics, since there appears to be no ground wire. Meanwhile, you should be able to wire white to white, and red from junction to black of motion detector. It won't break anything if there is no ground. It's possible that the junction box itself is grounded, and the grounding of the detector's white cover will happen through the screw, or you have to run a separate copper or green wire from a bonding screw in the back of the box (you'll need to add a screw) to the green wire terminal of the detector. – P2000 May 21 at 16:54
1

You could try it it will work or it won’t but it will not fry it.

I would pull a ground from one of the boxes that has it.

Pulling in a separate ground has been code compliant for a while now. The ground has to come from a circuit fed from the same panel or you could tie at your grounding electrode system if closer (not usually)

There are a few motion lights that require the ground if this is one of those it won’t work but it won’t fry it so try it and you might want to pull a ground even if it works just to be safe.

Updated for additional photos that were added. The ground may be from the conduit ? (if metallic) in that case the screw that shows the ground symbol would be a proper ground. The motion sensor output is red tie the red to the black of the new fixture and white to white. the concern with the new fixture getting fried is even lower as the existing fixture is controlling the motion sensor, as long as the maximum wattage for the motion light is not exceeded it should not be a problem. The only issue that may still come up is the new fixture may not work on the output of the motion sensor but again it won’t fry it as long as the maximum wattage is not exceeded. Electronic lights like CFL & LED’s may not work if the motion sensor is a simple SCR or silicon controlled rectifier / electronic switch that only turns on 1/2 of the sine wave. TRIAC’s or relay driven controls will normally work as they pass the entire waveform when turned on.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.