HELP Cant Figure Out Why High Bay Lights Flickering

[3oFElectric]

I'm troubleshooting some UFO high Bay lights in a shop. There are 6 lights. They're rated AC85 -277V. They're plugged into a 120v outlets in the ceiling.

They're flickering in unison.

When I unplug one light at the outlet box that powers the rest of the lighting plugs down the line, and plug in another exact same type of light into the outlet, they all stop flickering.

When I disconnect that light from the outlet, they all start flickering again.

I'd like to understand why this is happening.

Voltage to the 1st outlet box is fine and steady. All connections are tight.

The lights are 300 watt each on a 20 amp circuit.

Here's a link to a short video showing what I'm talking about -

Thanks!

 

[gwild]

I'm troubleshooting some UFO high Bay lights in a shop. There are 6 lights. They're rated AC85 -277V. They're plugged into a 120v outlets in the ceiling.

They're flickering in unison.

When I unplug one light at the outlet box that powers the rest of the lighting plugs down the line, and plug in another exact same type of light into the outlet, they all stop flickering.

When I disconnect that light from the outlet, they all start flickering again.

I'd like to understand why this is happening.

Voltage to the 1st outlet box is fine and steady. All connections are tight.

The lights are 300 watt each on a 20 amp circuit.

Here's a link to a short video showing what I'm talking about -

Thanks!

I was wondering if you were able to resolve your issue with flickering lights. I am having the exact same issue and have tried everything I can think of to fix this issue. This has been really frustrating as I have spent a couple of days trying to figure it out. I look forward to your replay. Thank you in advance.

 

[3oFElectric]

I was wondering if you were able to resolve your issue with flickering lights. I am having the exact same issue and have tried everything I can think of to fix this issue. This has been really frustrating as I have spent a couple of days trying to figure it out. I look forward to your replay. Thank you in advance.

Unfortunately I never did find out exactly what the issue was.

But by replacing the 1st light on the circuit, it stopped the flickering on all the lights. Not sure if somehow that 1st light was causing fluctuating voltage. But in the end that 1 replacement got all the lights to stop strobing.

Sorry I can't give you a more definite reason as to what was causing the issue.

 

[OldSparks]

We all know that LED lights are on and off at the frequency of the incoming power. I'm GUESSING that something in the circuitry of that "suspect" fixture is different. Something is, I think, causing the "off" portion of the usual 60 HZ flicker to maybe double, making it visible. Just spit balling here. I'd place an isolation transformer in series with the "suspect" fixture to determine if the power to the other lights is being affected, or if (a long shot) some kind of RF emission is involved.

 

[ramsy]

having the exact same issue and have tried everything.. This has been really frustrating

What is your lighting rep doing?

 

[J2H]

We all know that LED lights are on and off at the frequency of the incoming power. I'm GUESSING that something in the circuitry of that "suspect" fixture is different. Something is, I think, causing the "off" portion of the usual 60 HZ flicker to maybe double, making it visible. Just spit balling here. I'd place an isolation transformer in series with the "suspect" fixture to determine if the power to the other lights is being affected, or if (a long shot) some kind of RF emission is involved.

I’m certain that most LEDs are supplied from switch mode supplies and are not directly affected by the “off” portion of incoming power.

Perhaps there was a failed component of a harmonic filter in the power supply of the offending fixture, which is introducing harmonics and affecting the other fixture.

 

[Fred B]

Did you put the offending light in a different location and still replicate the flicker?
But if you put a different fixture in the location of the offending fixture and all flicker stopped would suspect that the fixture is bad from factory.