Occupancy sensor switch with CFL bulb light fixture

[BetaB4]

I want to put in an occupancy sensor wall switch to control a new ceiling light that uses a CFL bulb. The switch I want to get is a Leviton PR-150-1L.

When I read the product specs online, it says it can be used to turn on "incandescent and Rapid Start Magnetic fluorescent ballast lighting loads". Here's the link to the product info:

Is a CFL bulb a "Rapid Start Magnetic fluorescent ballast lighting load"? Nothing in the specs mentions CFL lighting fixtures, just "Rapid Start Magnetic fluorescent ballast lighting loads" -- whatever that is.

Also, this light fixture is at the end of a wiring circuit. The existing fixture is just a bulb holder with a pull chain to turn it on and off. I'm going to eliminate that fixture, replace it with a CFL-bulb ceiling light fixture (with no pull chain), and run a new wire from the light fixture to the new occupancy sensor switch. I was thinking that to do that, the new wire to the switch would be a "switch loop" since the power is at the light. I think that means that the switch loop will have a black wire at the switch and a white wire that is coded black -- in other words, essentially just two "black" wires at the switch and no neutral white wire. Is that correct? Will I be able to wire the occupancy sensor light switch with just these two "black" wires coming to the switch?

[RBM]

The CFL does not have a magnetic ballast, so most likely that motion sensor won't work. Your wiring scheme is correct however, I would run a three conductor cable to the switch location, as some motion sensors do require a neutral. I'm not sure if anything is currently on the market that will control a CFL, but in all likelyhood, it won't be long before something becomes available. My guess is that anything that will control a load as small as a CFL will probably require a neutral to operate, so be prepared if you're doing the wiring ahead of time

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[RBM]

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[HeyBub]

Considerably less trouble is a gizmo that screws into the existing socket with a motion detector built in. I've got one in the laundry pantry. Works swell. I open the doors, the light comes on.

I have to remember to close the doors, else someone putzing around in the adjacent breakfast room will trigger the light.

[DerbyDad03]

What's different about a motion sensor that would prevent it from operating any bulb screwed into a standard socket?

Doesn't it just close contacts that pass power to the fixture? How would it know what's screwed into it?

(It's late and I haven't learned anything new today, so hurry up with an answer!)

[RBM]

What's different about a motion sensor that would prevent it from operating any bulb screwed into a standard socket?

Doesn't it just close contacts that pass power to the fixture? How would it know what's screwed into it?

(It's late and I haven't learned anything new today, so hurry up with an answer!)

I think the manufacturers try to build devices like this to replace existing switches. They get their power by allowing a small amount of current to flow through the lamps that are being controlled, or some use a leak to ground system. If the load being controlled is to light, not enough current can pass through to operate the control without lighting the light. The devices like this that use a neutral are much more versatile, but are limited to locations where a neutral exists

[gfretwell]

I have several of these "2 wire" occupancy sensors and a single CFL is not enough load to make them work right. They are powered through the load. A 25w incandescent bulb is plenty tho, then you can have the CFL too. In my garage I have a couple CFLs and one small incandescent, it works fine.

[Don Klipstein]

CFLs are not such loads, and are not recommended except for CFLs rated specifically to be usable with dimmers and electronic switching devices.

CFLs rated to be usable with dimmers will probably be OK even if not overtly rated for electronic switching devices, but my warranty against damage to the CFL or the switching device or the building/contents/occupants shall be limited to what I got paid to post this... :) :)

As I hear it, that is correct - black tape wrapped around both ends of the "switched hot" white wire.

Those I don't know too well - though I doubt you need any cable to have both two hots and a neutral, though fair to good chance you need ground for every cable. According to that, to extent I know such well enough, ordinary "romex" should be OK.

If you have a cable with two "black wires", one of them switched, it sounds to me that you need a junction box somewhere, though many lighting fixtures have some enclosure allowable to use as a junction box (provided proper fittings around all cables such as "1/2 inch connectors" or the like is provided for and used). Also, ground wires of every cable must connect to every junction box that the cables enter. Anything used as a junction box, as well as every light fixture housing having a green grounding screw whether or not the light fixture is used as a junction box, needs every cable entering such to have a "grounding conductor" (as opposed to "grounded conductor", which is "white wire") connected to the "green screw" or otherwise connected to the metal housing.

- Don Klipstein ( [e-mail])

[Don Klipstein]

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Most CFLs with magnetic ballasts integral within the "bulbs" (rare nowadays) and most CFL desk lamps with "wallwart ballasts" (also not very common) have low power factor. It appears to me that the switching device in question requires high power factor, meaning incompatibility with even many to most magnetic-ballasted CFLs. This also means incompatibility with most fluorescent fixtures for "bulbs" rated 22 watts or less (with exception for at least some rated specifically for 17 watts), especially not good with most to nearly all fluorescent fixtures with starters - regardless of wattage, though most of those are 22 watts or less and other than 27 watts, but a few "low power factor ones" may be among the few with starters and wattages of 26, 28, 30 and 40 watts, 1 bulb per ballast, maybe whatever 32 watt one with a starter that I have low expectation to find existing.

- Don Klipstein ( [e-mail])

[BetaB4]

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That's interesting that Hubbell has a model that is made for CFL's. I'll have to try to figure out where I can buy them -- I'm not sure who carries their brand.

[BetaB4]

I am amazed that the Leviton switch doesn't mention anything about this -- especially now that more and more people are using CFL's. And, it seems strange that there isn't a way to use the Leviton with a CFL at least in situations where there is a neutral already at the switch.

[BetaB4]

A good idea, but I don't know if that will work with a CFL bulb (based on what others have written here about how these motion sensors work).

[ransley]

I wonder, I use x10 with cfls and it said not to, I replaced a photocell that said its not for flourescent and I have 20 connected to it.

[Don Klipstein]

Many electronic switching devices use triacs. If a switching device using a triac and not designed to handle CFLs is used with a CFL not rated for use with such devices (or at least with dimmers), then either of 2 things may happen:

1. The CFL may not let through current at the time of each half-cycle of the line fequency that the triac is triggered. The triac's triggering mail fail to take hold, causing the triac to not conduct.
2. The triac may begin conducting at a time in each half-cycle when the voltage across the filter capacitor in the CFL is less than the instantaneous line voltage. This is more of a problem with dimmers. The problem here is that the filter capacitor would draw a spike of current to quickly charge up to the instantaneous line voltage. Repeating such spikes every half cycle may overheat the triac, copper traces on the circuit board that the triac is mounted on, or the filter capacitor or circuit board traces in the CFL.

- Don Klipstein ( [e-mail])

[bob haller]

couldnt the triac controller justt be fed to a standard relay?

[gfretwell]

The problem I see with CFLs on two wire OS is they don't turn off.

[Wayne Boatwright]

On Sun 19 Apr 2009 06:43:55a, BetaB4 told us...

Not knowing any better, I installed a Leviton motion sensor switch in our laundry room/pantry to control a ceiling light that has 3 13watt CFLs. Never had a problem with it working. Never occurred to me that it wouldn't. I don't know the brand, the these are just common CFLs from Lowes.

[Tony Hwang]

Hi, I use a dimmable CFL on motion sensor. It works fine.

[BetaB4]

Amazing. I just saw one of those at Home Depot and it plainly and specifically says that it works with CFL bulbs.

I should have done that from the get-go.