I'm replacing an old led light fixture that is on a dimmer knob. The new light fixture is also LED but motion activated. The instruction manual says do not install on dimmer circuit. Basically I want to know why not, and is it ok to disregard this warning if I don't care about the dimmer effect working?

This will be a temporary fixture until we get a contractor out to have some proper work done. I need to have motion lights as a security deterrent ASAP.

Basically can I install the fixture anyway? If not what do I need to do, would it be a simple wall switch replacement? Or the entire wiring needs to be redone?

2 Answers 2


The dimmer modifies the sine wave and the fixture may not work. many dimmers use silicone controlled rectifiers and only 1/2 of the energy wave is passed on even at full on. Only having half wave to work with can keep the fixture from working or may over heat and even damage components in the motion light.

Because the manufacturer states to not use this fixture with a dimmer it would be a code violation to do it.


No, you cannot.

It is a code violation to install a fixture contrary to the manufacturers instuctions.

It's also a dumb idea, but that's not why you can't do it. You might well destroy the fixture, for instance.

A simple switch replacement should solve the problem, and can be changed out later if you install a different fixture non-temporarily.

  • I see. So when it says "dimmer circuit" this means basically any circuit with a dimmer switch? And just replacing the dimmer switch with a standard on/off switch should work?
    – user123296
    Commented Sep 14, 2020 at 13:23
  • Correct on both points.
    – Ecnerwal
    Commented Sep 14, 2020 at 13:42

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