Why won't this timer work with CFLs?

[aka Larry]

We like to have our outside garage lights on for safety as do all of our neighbors on the street. Back when we bought our house I replaced the light switch with a programmable hard-wired in-wall timer like this one:

For some reason CFLs will not work when using this timer. I don't really understand since all the timer does is switch the 120V on/off at the programmed times.

The timer works fine with the halogen post lights, but they ain't cheap (good light output though) and they don't last anywhere near their advertised 2 years+. The CFLs inside the house were installed 4 years ago and everyone is still going strong so I'd like to use them outside also.

Thoughts?

 

[Elite130]

I would like to know as well why switches specify incadesant vs CFL and (I assume to be soon) LED.

 

[nine4gmc]

CFLs have built in ballasts

 

[eljefino]

Usually when you run into this problem it's because the switch bleeds a little load through the incandescent filament to run its own stuff. I see enough wires that shouldn't be an issue: eg there's a neutral hook up.

What if you have a bunch of CFLs and one 15-25 watt incandescent?

 

[Falcon67]

Lots of timers and motion sensors do not work with CFLs or don't work well. Halogen is more like a regular bulb.

Here's one that claims to work with electronic ballasts:
http://www.leviton.com/OA_HTML/ProductDetail.jsp?partnumber=6124H-W&section=44955&minisite=10251

 

[ddawg16]

A bit more on the subject....

Older wiring setups did not include a neut in the switch box. Hence, a lot of the occupancy sensors, timers, etc use leakage current to power them.

When your using an incand bulb (halogen is an incandescent with halogen gas in it), you have a full 120vac across the timer even though the light is off....this powers the switch/timer. When it turns on the light, it has a bypass resistor that gives the switch/timer enough power to keep it going.

CFL's and LED's don't have this low resistance path....until you reach a certain voltage to turn on the AC/DC switcher in it, they look like a high impeadance.

 

[Gary S]

Florescent lights require a clean on-or-off switch to operate. Electronic switches are sloppy and never turn fully off. You need a mechanical switch to get a clean OFF switch. Electronic switches leak power in the off position and confuse low current drain lights like florescent and LED.
If you want to use an electronic switch to do this job, you need a mechanical relay between it and the lights so you get a 100% OFF switch.

 

[GpzGuy]

Depending on where you live and your outside temperatures, you may want to rethink using CFLs outdoors if it gets really cold there.

 

[dimarcelli]

I use intermatic KM2 mechanical timers. I've never had a problem with one. You can get them for $25.

KM2ST-1G is the part number for a single gang.

 

[theoldwizard1]

I use intermatic KM2 mechanical timers. I've never had a problem with one. You can get them for $25.

KM2ST-1G is the part number for a single gang.

Yep !

I will bet that digital timer uses a TRIAC to drive the load. Cheap ones are known to have "issues" when they turn off/turn on every half cycle.

 

[pop pop]

I didn't think CFL's were supposed to work. Saves electricity when it's dark.

 

[aandpdan]

Use the Intermatic ST01 series. It uses a relay to switch the lights and does NOT require a neutral.

It's battery operated.