SIGforum
LED ceiling light stays dim when off

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https://sigforum.com/eve/forums/a/tpc/f/320601935/m/7610032915

January 25, 2026, 11:38 AM
Hamden106
LED ceiling light stays dim when off
Other lights on circuit do not.
Been that way long time. I finally got my dumb kid (a doctor BTW) to see if wires are black to black.
I will go to Portland tomorrow.
My question is what can be on a circuit to keep an off light showing dim like a brown out?
I believe the fixture is a flat pancake LED. No bulb type



SIGnature
NRA Benefactor CMP Pistol Distinguished
January 25, 2026, 12:09 PM
Fly-Sig
Dumb question: Are there any possible UV sources nearby? We have a few plug-in flying insect traps that have a low power UV led in them to attract the insects to the sticky card. I notice the ceiling LED lights look like they're very dimly on, but it is the UV black light effect.
January 25, 2026, 12:27 PM
eyrich
Is it on any kind of smart switch or dimmer - basically anything but a dumb paddle or rocker switch?

Some smart and electronic dimmer switches, especially ones without a neutral, pull a small amount of current through the light to power their electronics. For incandescent and most florescent this isn't enough power to cause any light. But for LEDs this is enough to dimly light them.




January 25, 2026, 01:59 PM
400m
If your dumb kid is a doctor I want to know what your smart kids do. Big Grin
January 25, 2026, 02:09 PM
nshumway
Exactly what I was thinking. I have some smart switches that have a neutral and still pass a small current. Since other lights do not, are they different brand led bulb?

quote:
Originally posted by eyrich:
Is it on any kind of smart switch or dimmer - basically anything but a dumb paddle or rocker switch?

Some smart and electronic dimmer switches, especially ones without a neutral, pull a small amount of current through the light to power their electronics. For incandescent and most florescent this isn't enough power to cause any light. But for LEDs this is enough to dimly light them.

January 25, 2026, 02:27 PM
Pipe Smoker
I have an LED light in my bathroom that sometimes flickers at an intermediate brightness setting. My electrician told me that a more expensive triac dimmer would fix that problem.

That might fix your problem too.



Serious about crackers.
January 25, 2026, 02:53 PM
SW_Sig
I have a LED floodlight outside that is dim when off. It has been that way since I installed it 4 years ago. It is still n a paddle switch, no dimmer.
January 25, 2026, 08:32 PM
Lineman101
This guy does a lot of electrical stuff

https://www.youtube.com/watch?v=_bgUy6zA0ts

Might be the answer?
January 26, 2026, 11:08 AM
gpbst3
I just read something about this the other day. Basically some switches can "leak" current and the super high efficiency of the LED requires so little power.


January 26, 2026, 07:28 PM
jimmy123x
Your switch is leaking power through the circuit.
January 27, 2026, 11:36 AM
sreding
Maybe they switched the neutral and the leak is from the still hot line to ground through the fixture?

If you have a clamp on multimeter you could do some testing to see where the power may be coming from.




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