OT: under cabinet LED lighting delayed power on

[Veloo]

Question for the electricians/ electrically inclined.
We had under cabinet lighting installed with our kitchen renovation. 8 lights in total, LED, puck shaped.
They worked fine for a week or so then started to go on and off. Took a few minutes before the flickering would begin but the intervals were about 25 seconds on then 25 seconds off.
The electrician came over to "fix" it by changing the transformer. Fixed 4 of them but the other 4 were still going on and off.
He came by yesterday and changed the transformer again. No more flickering but there is a 5 second delay before the lights come on. Here's his reply:

"The time delay is normal, Sometimes a little bit longer sometimes a little bit shorter. When the AC is turned on to the transformer via the switch...
transformer windings get excited and convert the voltage from 120 VAC to 12 VDC and then it sends the CONVERTED voltage a long the wires and lights the LED that's the time delay.

That is perfectly fine ....there will be no more issues with the undercabinet lights we installed the larger VA transformer."

I'm not understanding why they worked for a week with no delay and now a delay is totally normal. Appreciate your input.

[parris]

I may be naive but just by what you're saying it sounds like the contractor's trying to cover his backside. We've got LED lights in various places and they don't have a delay like what you're experiencing. Maybe find the manufacturers site and see what it says for operation and such?

[wallymann]

Question for the electricians/ electrically inclined.
We had under cabinet lighting installed with our kitchen renovation. 8 lights in total, LED, puck shaped.
They worked fine for a week or so then started to go on and off. Took a few minutes before the flickering would begin but the intervals were about 25 seconds on then 25 seconds off.
The electrician came over to "fix" it by changing the transformer. Fixed 4 of them but the other 4 were still going on and off.
He came by yesterday and changed the transformer again. No more flickering but there is a 5 second delay before the lights come on. Here's his reply:

"The time delay is normal, Sometimes a little bit longer sometimes a little bit shorter. When the AC is turned on to the transformer via the switch...
transformer windings get excited and convert the voltage from 120 VAC to 12 VDC and then it sends the CONVERTED voltage a long the wires and lights the LED that's the time delay.

That is perfectly fine ....there will be no more issues with the undercabinet lights we installed the larger VA transformer."

I'm not understanding why they worked for a week with no delay and now a delay is totally normal. Appreciate your input.

a slight pause seems fair. we have LED flood-lights installed where we used to have R40 incandescent, they're just screw-in replacements that work with the existing in-ceiling cans. flick the switch and *all* of the lights delay by a second or 2. there's quite a bit of in-bulb circuitry associated with the voltage transformation going from 120VAC to 12VDC, and it takes time for the electrons to do their thing.

[Veloo]

I can live with a one second delay but I've timed the delay MANY times yesterday and minimum delay is 3.3 seconds and so far max is just over 5 seconds. This just seems high to me.

[rwsaunders]

Write/call the transformer manufacturer and ask their opinion. Perhaps try calling a local electrical or lighting supplier...The Home Depot too...and ask the same question as well.

[eippo1]

Not an electrician, but do specification work as an architect. LED's are still relatively new and as such many people are coupling the wrong drivers with the lights, causing problems with turn on, dimming, etc.

The fact that he is using a transformer vs a driver in the first place makes me think he doesn't know much about LED lights. Get a new guy to look at it that knows LED lights and can talk to the manufacturer to get the correct drivers.

See links below:
http://www.ehow.com/info_12179587_differences-between-led-drivers-low-voltage-transformers.html

http://www.pegasuslighting.com/led-drivers.html

[old fat man]

We just renovated our kitchen/family room, and I notice that the LEDs in the family room (further from the electrical panel and controlled by multiple switches) take longer (maybe a second) to turn on when using the switch in the kitchen as opposed to the switch in the family room itself. I think it has to do with how they wired the setup. I bet there is room for improvement in the wiring setup.

[c77barlage]

It sounds to me like a lighting control and/or power supply compatibility issue.

Are these lights controlled by a wall switch, wall dimmer or some sort of integral switch? If controlled by a dimmer, the dimmer needs to be compatible with LED lighting loads. Also, if dimmed, certain dimmers need a minimum amount of electrical load to perform optimally.

[BSUdude]

Not an electrician, but do specification work as an architect. LED's are still relatively new and as such many people are coupling the wrong drivers with the lights, causing problems with turn on, dimming, etc.

The fact that he is using a transformer vs a driver in the first place makes me think he doesn't know much about LED lights. Get a new guy to look at it that knows LED lights and can talk to the manufacturer to get the correct drivers.

See links below:
http://www.ehow.com/info_12179587_differences-between-led-drivers-low-voltage-transformers.html

http://www.pegasuslighting.com/led-drivers.html

Yea. I would try getting ahold of a manufacturer's rep for your system and see what they say. The best case would be if you could get the manufacturer's rep, electrician, and yourself in the same conversation. That would make it readily apparent if the electrician knows what he's doing or not. What you're experiencing is not normal or acceptable operation.

[DreaminJohn]

Yea. I would try getting ahold of a manufacturer's rep for your system and see what they say. The best case would be if you could get the manufacturer's rep, electrician, and yourself in the same conversation. That would make it readily apparent if the electrician knows what he's doing or not. What you're experiencing is not normal or acceptable operation.


I agree with this, and your best chance to realize it is to call or visit the electrical supply house. Hopefully your guy didn't buy this stuff from Home Depot and can point you to where he obtained the components.

If you go there you may be lucky enough to find the in-house expert but at the very least they should be willing to direct you or even make the call for you.

Please don't take this as a lecture, but I've found a supply house to be one of those places where kissing butt will take you a looooong way and anything else will likely result in a, "sorry, can't help you". Remember these folks don't typically deal with the end user; they're used to contractors.

Good luck.

[fogrider]

I converted the lights in our living room to LEDs. this is 12 four foot tubes. when I installed the first two the light pretty much came right on, there was very slight delay, maybe 1/3 a second. I didn't think much of it.

I am replacing fluorescent tubes and had to pull out the ballast and there were no transformers. so the lamps are connected directly to AC power.

As I connected up the other lamps, the delay got longer and longer. With all the lamps in place, there is about a 3 second delay but it all works fine.

[Veloo]

Thanks for all the feedback.
I'm not using a dimmer for these lights. The same lights are used for in-cabinet lighting as well. There are 3 of these and they have worked fine but these are direct connect - not hooked up to a transformer.

I found some specs on the lights and transformer. Hopefully I can get some feedback from them.

Liteline UCP-LED3
12V DC 165 mA
Use class 2transformer only
Maximum 10 puck lights per transformer

Transformer
Brand: P ADAPTOR
LYD1206000
INPUT100-240V~, 2.5A 50/60Hz
OUTPUT: 12V - 6A

Scary thing is when I try to find the transformer manufacturer, I get a bunch of Alibaba hits.
Logo is the same as this: http://sz-lyd.en.alibaba.com/product/485051535-213035058/12V_6A_AC_DC_adapter.html

[Louis]

I have two screw-in sockets in my garage ceiling, both on the same switch. In one of them I have an incandescent bulb, in the other an LED. When turning on the LED lags the incandescent by a fraction of a second.

IMO if nothing else in the area is providing light, then a lag of more than 1 sec is too long to be acceptable.