View Full Version : photoelectric eyes and CFL bulbs

09-19-2007, 01:53 PM
I want to add electric eyes to my driveway's lamp post and the light over the garage door. In reading the packaging for the eyes, I find that they are to be used with incandescent bulbs only.


09-19-2007, 02:15 PM

Seriously, it is because they have not been tested by UL for such use. It may also be because you were looking at two-wire photocells and these draw a small amount of electricity through the filament of an ordinary incandescent bulb to operate, even when the light is off during the daytime.

I have a three-wire photocell on my outside lights and it works just fine with CF lamps. The three-wire photocells have both hot and neutral leads along with a switched lead for the lamp.

Ian Gills
09-19-2007, 02:38 PM
Yep, two-wired photocells are useless for CF bulbs. They will work but the CF bulb will flicker at dusk and dawn and you will go through CFs every few weeks.

09-19-2007, 03:56 PM
Note depending on where you live, many of the cf bulbs don't work well if at all at very cold temperatures. Now, if you live in Hawaii, you probably don't have to worry - it will probably corrode the base before the buld dies.

09-19-2007, 08:07 PM
The electric eye device that I wanted to buy was a socket adapter. I have no idea how many wires it has. I just wondered why it would make any difference at all.

Yes, I'm in a very cold clime where sub-zero temps in the winter are not uncommon. I've had my lamp post fluorescent light that is about to see its fifth winter, so that's not a problem. When first turned on, it gives off a pinkish glow for the first couple of minutes (winter OR summer), then illuminates in a very normal manner the rest of the time it's on. The light over the garage door is new this year and I don't know how long it will last, but it's been on more than it's been off for the last six months without any problems. Winter may tell a different story for it later.

09-19-2007, 08:21 PM
Most likely that socket adapter photocell is a simple one, which would fall in the category of a "2-wire". They operate by "stealing" electricity, meaning they allow a tiny amount of current to flow when the bulb is off. This current powers the device so it can switch the lights on at dusk. A regular bulb never notices a few milliamps, and does not light up or even glow. Because a CFL is an electronic device, this attemp to feed a small current through it causes flickering, and is bad for the bulb.

With modern bulbs, you have to be very careful with any type of dimmer, photocell, or motion sensor. Some controls say "no flourescent", some say "magnetic ballast" only, some say "electronic ballast" only. You have to know what you have, or as Clint Eastwood would say, a man has to know his limitations!

09-20-2007, 12:01 AM
Socket adapter = 2 wire....no worky.

Spaceman Spiff
09-20-2007, 07:04 AM
I just bought some CFLs that say min starting temp is -20F! I'm going to put them in a bunch of my outdoor fixtures now...

09-21-2007, 09:27 AM
I just bought some CFLs that say min starting temp is -20F! I'm going to put them in a bunch of my outdoor fixtures now...

They really are fantastic. I was using these wherever I could long before Al Gore became a movie star. Since then, I've found that the big box stores are displaying a bountiful selection for almost every application. It's really great.

By the way, for any of you who have Christmas shopping headaches for Grandma, these bulbs actually make nice gifts - much more appreciated than that bathrobe and slippers that will just sit in a closet with fifteen others that she doesn't use! They're also nice for those grab-bag exchanges. Who doesn't want to cut that electric bill down a little?