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Tech Forum

February 2017

LED Compatibility?

I replaced some outside 60W bulbs with CREE dimmable LED replacements. The lamps are  controlled and dimmed using X10 switches. When switched off, the lamps still glow at about 20% and will not shut off completely unless I use the disable feature of the switch. However, this prevents the timer from automatically controlling the lights. What causes this and is there a fix, or are LED replacements not compatible with X10?

Christoffer Mortensen
Piscataway, NJ


They're compatible; what you're seeing is the leakage current on the output of the X10, which is still enough to cause the LEDs to light up barely (and which isn't visible on incandescents.) If you truly want the LEDs to go out, though, you'll have to look for something better than the old X10 designs.

Ralph Phillips
Shreveport, LA

LED's use much less current than incandescent bulbs. Even just a few milliamps of leakage current through the X-10 modules can be enough to keep them glowing quite a bit. As a workaround, I've gotten around this problem by putting a low wattage (like 15 watts) incandescent bulb into a second socket.

William Barnett
West Haven, CT

Conventional x10 switches require a small current to run through the load (i.e. an incandescent light) in order to work correctly. For non incandescent loads such as CFL or LED lights you need a x10 switch specifically made for them. I currently use a WS13A x10 wall switch and also an XPFM x10 fixture module to switch LED lights (and CFLs). These x10 switches are not dimmable though. In general, LED lights need a dimmer specifically made for LED lights. I have had a good success with Lutron CL digital dimmer (e.g. MACL-153MH) as a manual dimmer but I do not know of an x10 compatible dimmer designed for LED lights. Perhaps someone else knows of one that will work.

Dan Koellen
Roseville, CA

I go through this problem whenever I use x10 in a small project. x10 appliance modules need some kind of load resistor, but due to the 110VAC appearing when it turns on, I do not advise it. Instead, a batter way to solve it is to connect a 110VAC relay parallel to the LED bulb. If you want to use a resistor 33K 1W will be OK (I tested up to 42K that works), BUT be very careful about insulating the wire leads. I tested both methods (resistor turn on only a second in on state), they work perfectly.

Ankur M Bhakta
Tulsa, OK