Under-cabinet lights only bright when other device plugged into socket.


  #1  
Old 10-20-17, 05:03 AM
J
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Question Under-cabinet lights only bright when other device plugged into socket.

Hi! I have an issue where I have a switched outlet which has the transformer for my under-cabinet lights plugged in. The lights are very dim, unless I plug something else into the other plug of the same outlet (also switched). I've tested this with my LED strip lights which run above my cabinet (they use a transformer as well), and also a standard desk lamp. Both cause the under-cabinet lights to illuminate brighter than they would if nothing was plugged in along with them. The desk lamp causes just a little additional illumination, while the LED strip causes the under-cabinet lights to glow multiple times brighter.

I don't understand how/why this would be -- here's a video which shows what's happening.

https://photos.app.goo.gl/UcGJ1CXALI3qZMyB3
 
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Old 10-20-17, 05:21 AM
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Does that outlet work normally when only a desk lamp or other appliance is plugged in ?
Geo
 
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Old 10-20-17, 05:25 AM
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I would start by replacing the outlet. I wonder if there is a poor connection inside your outlet. Plugging another device in may be helping complete the circuit.
 
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Old 10-20-17, 05:59 AM
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Videos do not play on my computer (or at least take hours to load) so these questions are based on not haveing seen your video.

When you plug in the desk lamp and then switch it on and off do the undercounter lights change?

If you exchange the plugs of the undercounter lights and the desk lamp, is the behavior different?

Does anything change when you flip the switches that control the receptacles (outlets)

Pull a plug out a little ways, not enough for the light in question to extinguish completely and measure the voltage at the two power prongs. What voltage do you get for each plug?

An analog meter (with a needle in the meter dial) works best. A digital meter (with a numeric readout) may give unreliable readings if there is nothing plugged in and turned on at the point being tested.

If you are about to ask, what should be plugged in where when I flip the switch?, the answer is, try it for all combinations.
 
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Old 10-20-17, 06:18 AM
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I will mess with the outlet/plug configuration more when I get home.

Turning the desk lamp on/off toggles the brightness of the under-cabinet lights. I should test with a higher wattage bulb and see if my theory that the more power device #2 consumes, the brighter the under-cabinet lights will glow!

I think I tried both plugs but will confirm later tonight.

Both receptacle are on the same switch so I cannot turn them on/off independently.

I will try to measure the voltage when I get home.

Thanks!
 
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Old 10-20-17, 06:35 AM
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First off, although it is likely not the cause of your issue, you should not be using Romex as a cord.

The cause is likely you have something wired in series instead of parallel.
 
 

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