photocell + CFL don't play well with DSL

Outside the front door of our house is a wall lantern controlled by an indoor switch. Last year, I replaced the incandescent bulb in the lantern with a CFL. The lantern had a 20-year-old photoelectric cell, the type that screws into the socket, which I left in place when I installed the CFL. (Bad idea, I know. But I didn't know any better at the time.)

Subsequently I began experiencing mysterious interruptions and slowdowns with my home's DSL connection at night. Eventually I figured out that whenever the wall lantern circuit was switched on, the DSL petered out. Upon turning off the switch to the lantern, the DSL returned to normal operation.

Then I learned here that certain photocells are incompatible with CFLs. So I removed the photocell, leaving the CFL installed, and the DSL issues ceased. Apparently, the photocell + CFL combination produced interference that the DSL couldn't handle.

I suppose I could install a CFL-compatible photocell in the lantern, but we don't use that light often (we have a post light in our yard that illuminates the front door somewhat), so for now I've decided to leave the lantern without a photocell and just control it by the switch.

Can anyone recommend a photocell that works well with non-dimmable CFLs? I prefer one that can be retrofitted to an existing fixture, although based on what I've read, it seems that the screw-in type doesn't pass muster.

It definitely won't be the screw in type. Check out http://intermatic.com/

I have DSL. l I have a lot of CFL. I have one porch light on a motion sensor, but it is an incandescent bulb. I have no trouble with the DSL, so you might be right about that specific photocell/cfl combo causing trouble.

First, I would shield the photocell so you are absolutely sure that it gets no reflections or direct light from the bulb. You should be aware that you can get enough reflection off clear glass to operate a photocell. The photocell should be "looking" outside with no glass or metal in a position to obstruct or reflect on the photocell.

If the photocess can see the light from the bulb it will create a chaotic situation on the circuit.

If that doesn't work you could try connecting the photocell to operate a miniature electro-mechanical relay with 120 Volt coil, and let the photocell operate the relay. You should try to find a relay small enough to tuck in into the area where the fixture is connected to the house wiring.

It may work, and it may not.

Thanks for the replies. Here are some of the possibilities I uncovered.

At my local Home Depot I saw light controls made by Westek (parent company: AmerTac). One model, the SLC6CBC, is a screw-in that reportedly works with CFLs. At $10, it's a few bucks more expensive than the incandescent-only type, but still reasonable. It can be programmed to keep the light on for 2, 5, or 8 hrs., or until dawn.

Intermatic makes a couple of screw-in photo controls designed to accept CFLs: the NE200C, which is designed for flood lights and looks like it might be too tall to fit in a wall lantern with a CFL and its ballast; and the NE3BC, which shuts off automatically after 6 hours -- apparently the duration is not programmable. Not sure which, if any, retailer near me stocks these.

Heath Zenith, a brand stocked at my local Lowe's, offers motion sensor add-ons, but none seem to accept CFLs. The site that contains information on their products appears to have been hacked, and Heath Zenith doesn't have a great reputation for quality based on what I've read online.

RAB Lighting makes a Smart Lantern motion sensor with built-in photocell, but it's costly (about $50), and I'm not sure I need motion-sensing capability for this particular lamp, especially at that price.

So it looks like Westek may be the best bet right now.