LED support for wall switches

pete6032

Diamond Member
Dec 3, 2010
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3,442
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I recently purchased a timer wall switch for my bathroom ceiling fan, which has a light bulb in it. The ceiling fan has a standard bulb base and we put an LED bulb in the fan light. The timer switch I purchased says "INCANDESCENT" on the box, which I did not see before buying. I installed the switch and now the bulb in the ceiling fan is flickering ever so slightly, enough to be annoying. Sometimes I can get the bulb to not flicker by turning the switch on and off multiple times, but this isn't a long term solution. I can't seem to find anywhere on any bathroom timer switches whether they will support an LED bulb. Is there something I need to look for on the timer switch to indicate its compatibility with LED bulbs?
 

herm0016

Diamond Member
Feb 26, 2005
8,503
1,117
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the light or light /fan combo may have integrated LEDs.

that's like saying the permanent electrical system of your home should be made of the cheapest crap just like the light bulbs. no thanks.
 

Paperdoc

Platinum Member
Aug 17, 2006
2,440
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Perhaps you should check the fan / light fixture for loose wiring or a poor connection, even in the lamp socket. If the lamp receives a constant power supply, there is no reason for flickering. And no common switch or timer should do what you describe. But a loose connection in the fixture, constantly subject to vibrations of the fan motor, might cause very short disconnections. If that is happening, it would not make a regular incandescent bulb flicker because their hot filaments do not respond to very short power changes. But an LED can respond quickly.

Try these three tests.
1. Temporarily replace the LED with a regular incandescent bulb. If that does not flicker, then you have confirmed that the flicker is caused by very short power changes.
2. CAUTION! Be very careful with this, and maybe do NOT try this if you are no familiar with handing live electrical circuits. At the timer switch, rig a temporary bypass of the switch so that the fan / light gets power and turns on when the timer is OFF. See if that changes anything with the LED lamp. If the flicker still happens, the problem is in the fixture. If the bypass eliminates the flicker, the cause is in the timer.
3. AGAIN, CAUTION! IF it is possible, at the fixture disconnect the power lead to the fan motor so it can't run. Turn on via the timer switch. If the flicker disappears when the motor is stopped, but happens when the motor runs, then the motor vibrations may be contributing to the problem., as I suggested at first.

One last possibility to consider (relates also to that last test I suggested). The fan MOTOR is NOT an "incandescent lamp" device. That timer may not have been designed or rated for such a load. As a start, check the electrical rating of that timer - particularly, the Amps, maybe the Watts. If it is low (say, less that 5 Amps or 600 W), it may not be suitable for that application.