Under cabinet dimmable LED woes

[username5000]

I recently installed 24 (total) under and above cabinet lights in a customers home. They are Patriot lighting 16" and 12" slim (model# 0033-0011). They are 120v 10w dimmable and in the specs it says "internal driver-no external driver needed." The dimmer switch is a Lutron Ariadni 250w led dimmer. No matter what... they flicker. But just barely and for only 3-5 seconds at a time then go back to "normal". Its very subtle but its enough that the customer doesn't like it.


So..the setting

Neutral is in the switch box so I have 120v in switch box.
leaving switch box out to first light is 12-2 romex w/ ground. It comes out a little hole just below the cabinet.
Another 12-2 w/ ground goes from 1st cabinet to the second cabinet. Daisy chained from cabinet to cabinet to cabinet.
There is a thin junction box below each cabinet to catch the daisy chain and the lamp cord that plugs in to the light.
Some cabinets require a 12" and a 16" light to be installed. In these cases only one light is hardwired in the box. The other is fed from a linking cord allowing one light to output 120v to the other. Specs say a max of 20 can be linked together. In this installation no more than two are ever linked.

What I have tried

First I removed the switch and just wire nutted the hot and switch leg. Still flickered.
I turned off every breaker in the house except for the circuit in question and turned off each under cabinet light with the little switch on the light itself. (on/off type not hi/lo/off)
Every light, individually, still flickers. With the switch bypassed.


Has anyone ever come across something like this before? I know it says no driver needed but would adding one help? I ran the two extra wires just in case but since the product says none needed....

Any help or insight would be appreciated
Thank you all

 

[username5000]

Also..

Also..

The house has a security system. When I turned all the breakers off the security system went into backup mode and beeped the whole time so it wasn't "off". Can security systems cause interference?

The home also has a 400a service. 2 200a 54 space cutler hammer with the brown breaker switches. Maybe a ground loop or improper grounding?

anyway...just thinking

 

[LarryFine]

First I removed the switch and just wire nutted the hot and switch leg. Still flickered.

That's all you need to know. There is an issue with the lights themselves, or the power itself.

If every light does it, I would try one somewhere else, like your own house.

 

[LarryFine]

Can security systems cause interference?

Extremely unlikely.

Maybe a ground loop or improper grounding?

Also extremely unlikely.


Troubleshooting is a process of elimination. If you can not get the lights to be steady on another power source, it's the lights themselves.

 

[Dennis Alwon]

I agree with Larry. Although I think the lights are the likely problem. I say this because the problem goes away. If it was bad power then I would think the issue would be there more often. Some led's have a delay in coming on so if it is just for a brief second I would either try another brand or convince the home owner to live with it.

 

[winnie]

The internal driver circuitry in the led units may be picking up noise. I agree with the above...Try a led unit someplace else.

-Jon

 

[kwired]

I know it says no driver needed but would adding one help?

It says no driver needed because there already is an internal driver. Where do you propose to add one?? All the driver is is a conversion item from supply voltage to whatever the LED('s) needs for supply.

 

[username5000]

It says no driver needed because there already is an internal driver. Where do you propose to add one?? All the driver is is a conversion item from supply voltage to whatever the LED('s) needs for supply.

Right, like a ballast. I know. What I meant to say was ...Is there anything I can put, say line side of the switch, that would maybe "clean up" the power or filter out any interference?

Thanks for the responses by the way.

 

[PetrosA]

If the lights are all flickering together (in unison) with all the other circuits in the house shut off I would suspect a driver issue, bad shielding perhaps, or picking up some radio interference via the LED tape/PCB in the unit. I would definitely try the lights in another building to see if that makes any difference. I had a similar issue a few years ago with WAC LED track heads with integrated drivers (not the external kind that sit against the track) and it took two visits by a manufacturer's rep to witness the issue and trials with other heads to prove that it actually was the LED track head at fault. Even then, they tried to get out of refunding me for the 40 track heads but had to once we proved it was an issue with that head.

 

[brantmacga]

The only other thing I could recommend is to check all the connections upstream of the switch.

I had to troubleshoot someone else’s install that was doing the same thing not long ago, and I found the issue was a poor neutral connection in an attic junction box.


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[kwired]

The only other thing I could recommend is to check all the connections upstream of the switch.

I had to troubleshoot someone else’s install that was doing the same thing not long ago, and I found the issue was a poor neutral connection in an attic junction box.


Sent from my iPhone using Tapatalk

Temporary supply conductor bypassing unknown connections you may be a place to start. If problem goes away, start investigating the original circuit or even abandon it.

 

[username5000]

Thanks for all the replies everyone. I was able to prove it was the lights themselves. I bought a different brand light and put it into the system. While all the others flickered it remained steady. We decided the lights would be returned. The customer will then buy new lights and I will install them free of charge. Thanks again everyone.

 

[jeremy.zinkofsky]

Thanks for all the replies everyone. I was able to prove it was the lights themselves. I bought a different brand light and put it into the system. While all the others flickered it remained steady. We decided the lights would be returned. The customer will then buy new lights and I will install them free of charge. Thanks again everyone.

Glad you figured it out. For future reference, LED lights need a constant current supplied to them. The driver is supposed to supply the LED with a current source that has little + or - variation. This variation is what causes the flicker. So, flickering almost always is either an incompatible dimmer switch or a bad driver.

After looking at the product cut sheet, I believe what you experienced was cheap or insufficient drivers. Typically you don't want to mess with any LED lights that come in a blister pack.