Erratic LED Lighting

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gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
170309-0817 EST

Jim M426:

Find a location where there is a good conductive path to the main panel neutral bus. This might be a copper or steel pipe in the kitchen sink, an EGC socket in a kitchen receptacle, or an extension cord or wire to the main panel. This is used as your reference for voltage measurements. I will call it a good ground point even though I don't like to call things a good ground because it is a poorly defined term.

Using a high input impedance meter, 10 megohms, and using the good ground reference as one meter input and with the LED not touching the can measure the voltage to the can, the LED neutral, and the LED HOT. Do this with and without power to the LED and under conditions which would cause your unwanted LED dim light.

The likely difference in voltage between neutral and the can EGC should be under 1 V. Not likely to be 0.1 V or less, and if it is 10 V there an obvious unexpected condition. As a suggestion with power off to the LED the LED hot voltage should be below 10 V.

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JFletcher

Senior Member
Location
Williamsburg, VA
I recently purchased an old Florida house that was in dire need of lighting (among other things). After replacing the 200A, 20 space panel with a 200A, 42 space panel I started doing electrical upgrades in the house. Thinking I'd save some electrical bill $$$ going with LEDs, I bought some LED can lights and dimmers that the lighting distributor approved as compatible. I settled on 3" and 4" cans with trims rated at 9 watts each.

For the kitchen and lanai lighting I ran a single 15A circuit fed by 14/2 NC cable. On that circuit are:
  • (6) 3" cans controlled by (1) Lutron Maestro MACL-153M and (1) Lutron Maestro MA-R (kitchen ceiling)
  • (4) 3" cans controlled by (1) Lutron Maestro MACL-153M and (1) Lutron Maestro MA-R (soffit)
  • (3) 3" cans controlled by (1) Lutron Maestro MACL-153M and (1) Lutron Maestro MA-R (island)
  • (6) 4" cans controlled by (1) Lutron Maestro MACL-153M (lanai)
  • (2) 3" cans controlled by (1) Lutron Maestro MACL-153M (above sink)
  • (2) 4" cans controlled by (1) Lutron Maestro MACL-153M (above bar)

When the lights in the lanai are on and I turn on the kitchen ceiling lights, the lanai lights brighten then dim back to where they were.

When the lanai lights are turned off (regardless of the state of other lights on the circuit) 5 of the 6 lights remain lit but very dim so you can only see it when it's dark. The only one that is completely out is the one first fed from the dimmer and through which the remainder are fed.

I did the installation a little at a time (I don't move so fast anymore) and the lanai & bar were the last sets of lights I installed. Everything seemed to work fine up to adding the bar & lanai lights.

Any thoughts on why the LEDs are acting up?

Thanks,
Jim
IBEW (retired)

Are the dimmers limited to 150W ea or the total circuit? You have 22 9W (198W) of LED bulbs on a dimmer(s) designed for 150W. wag.

re: saving money, 22 60-75W bulbs are burning up ~ 1.5kw-hr vs .2. Depending on how conscientious you are with turning off lights when not in use, that could make a significant difference in your power bill. Here, in this house, not using hot water unless necessary, limiting dryer/laundry loads, and only running the AC when needed/higher thermostat setpoint make much more difference in my power bill than the few lights I use.
 

Electric-Light

Senior Member
Are the dimmers limited to 150W ea or the total circuit? You have 22 9W (198W) of LED bulbs on a dimmer(s) designed for 150W. wag.
Per dimmer. He's got them spread across a whole bunch of them and he's well under the limit.

re: saving money, 22 60-75W bulbs are burning up ~ 1.5kw-hr vs .2. Depending on how conscientious you are with turning off lights when not in use, that could make a significant difference in your power bill. Here, in this house, not using hot water unless necessary, limiting dryer/laundry loads, and only running the AC when needed/higher thermostat setpoint make much more difference in my power bill than the few lights I use.
That assumes those lamps wouldn't be dimmed and left on at full power all the time. This is why manual-on, auto-off vacancy sensors are effective and minimally intrusive where lights do not have to stay on for a long time and not constantly occupied. Can be used together with a dimmer if you want. The duration of inactivity before shutting down is a balance between energy savings and comfort. It preserves all of the manual switch experience but takes care of turning off lights you forget to turn off. Minor inconvenience might be shutting off on you while seated out of view but many sensors have reactivate if it sees a motion within a short time of shut off.
 
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