Hi! I'm at my whits end with this one so here goes...

I'm currently installing recessed fluorescent T8 2-lamp fixtures in my garage, one of which I want to have powered by a Leviton PR180 occupancy sensor. After my initial installation attempt, the fixture flickered and it was then that I noticed that the fixture uses an electronic ballast and the switch is rated solely for magnetic ballasts.

Ok, no problem. I went to RadioShack, got myself a heavy duty relay, and wired everything up such that the occupancy sensor merely operates a relay that, when closed, provides a clean hot lead directly to the fixture.

This fixed the flickering, but now the fixture does not turn off. As it turns out, this occupancy sensor, like most on the market, does not operate correctly unless there is a specific minimum load on it. In other words, the relay coil does not provide sufficient load to allow the occupancy sensor to function correctly. I verified this by splicing a incandescent light fixture on the occupancy sensor in parallel with the relay; when this was done, everything worked as intended.

So the million dollar question... what next? Is there a quick and simple solution for allowing me to use my current fixture as is with the PR180 occupancy sensor? Is there something I can splice onto the sensor to provide ample, yet minimal, load on the line to allow this setup to work? Or should I just bite the bullet and keep trying to hunt down a magnetic ballast? I'm handy with a soldering iron so if there is a special component I could splice onto the line, I'm willing to give it a shot.

Specs on the occupancy sensor:
- Load Rating: 40W/VA Min 500W 400VA Max (per Leviton website)

Specs on the relay:
- RadioShack cat. #: 275-217 DPDT
- Continuous coil voltage: 132VAC
- Power consumption: 1.10VA max
- Rated voltage: 110/120VAC
- Coil resistance: 4.430 ohms max
- Pull-in voltage: 9.6VAC
- Dropout voltage: 36VAC
- Nominal coil current 8.4/9.2mA
- Contact rating: 10A @ 110VAC or 24VDC
- Minimum load 100mA, 5VDC

Thanks in advance for any and all assistance!

-Dan

KISS will probably be able to tell you what size resistor to add to the seensor to make it work.

Well, I should add to this that I tried using a 100 ohm 10W wirewound resistor (RadioShack 271-135) and it worked, but the resistors got sizzling hot.

Resistors have different heat dissipation ratings but I've forgotten how to read them. PM KISS

Why use a resistor? They only make heat. Use a regular light bulb and find the lowest wattage that will work, at least you are getting some light (along with the heat) for your electric $. Assuming 60 watts would be enough load for your sensor, you will need a 220 ohm 100 watt resistor, The cost, compared to a light bulb will be outrageous. Besides, you will have to mount it in such a fashion that it stays cool. Sounds like a lot more work that a porcelain bulb socket or cheap ceiling can.

As to that 100 ohm 10 watt resistor, at 120 volts it was trying to dissipate 144 watts! Sizzling is a mild word. Amazing that it didn't fail after a few minutes.

Edit: I reread the specs on your sensor. A 40 watt bulb should work. Or a string of 10 4w christmas tree bulbs in the windows. :D

Well, I was hoping to avoid having any fixtures protruding from the ceiling, thus the recessed fixtures. Plus, if I attach a porcelain light fixture, then there's really no need have the fluorescent fixture attached to the occupancy sensor since the incandescent bulb will essentially provide sufficient light. I think I'm slowly I'm leaning that way, though.

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Originally Posted by dpdevil16

Well, I was hoping to avoid having any fixtures protruding from the ceiling, <snip>

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Get a cheap ceiling can with a 40w bulb and put it somewhere that you would want a little extra light. The fluorescent fixture will do well for general, larger area illumination. I agree, the bare-bulb porcelain fixtures don't look nice and the bulbs are easy to break.

You will still have to deal with the improper operation when the light bulb blows out however. Now you will need 2 ceiling cans. :D

EPM

Since the reason for installing the occupancy sensor in the first place is generally energy conservation, think about skipping the resistor or incandescent loads, they waste a lot of energy and could present a safety issue as well. Change the part to a Leviton ODS10-ID. You'll need a ground (neutral) in the box but the part doesn't require a load and will work with both ballasts.

I hate being the devils advocate... but.. How many fixtures are you using? Are you aware that all fluorescent lamps life are greatly affected by continual switching? And all flourescents require some warm up time to reach full brightness, is that a concern? I appreciate your desire to experiment, but is this just for fun or for function? I'd like more info, if you don't mind.

Quote:

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Originally Posted by Missouri Bound

I hate being the devils advocate.....but.. How many fixtures are you using? Are you aware that all flourescent lamps life are greatly affected by continual switching? And all flourescents require some warm up time to reach full brightness, is that a concern? I appreciate your desire to experiment, but is this just for fun or for function? I'd like more info, if you don't mind.

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I don't mean to sound defensive, but there's no reason to play devil's advocate here. I presented the scenario, and I'm simply trying to find an answer, even if it takes some experimenting and brainstorming to formulate a viable solution. My reasons for finding an answer, while entirely legitimate, should not determine whether this post should receive feedback from the helpful folks on this forum. Honestly, I don't see what so unplausible about a scenario such as this.

But since you asked, I'm using five fixtures in a low- to moderate-traffic area, yet it is an area that would benefit greatly from an occupancy sensor switch. The fixtures in place DO NOT require a warm-up period to achieve full brightness.

Thanks to all that have provided useful information and suggestions on this thread and not questioned its legitimacy.

I hope you didn't take my comments the wrong way. I've had a lot of experience with occupancy sensors. We have installed them mostly in public restrooms (bad idea) where there is sporatic movement at best. What we have found out is that the lamps burn out prematurely, which requires attention. We didn't have the flickering problem with our installation, but because the sensor was adjustable to time out, unfortunately we had occupants left in the dark because of stalling or just physical need on their part. Then we adjusted the time up to allow a 15 minute delay, which just about eliminated the need for the sensors, since traffic assured at least one visitor in 15 minutes. But at least they were turned off at night. I'm not sure who made the sensor we used, but it was purchased at Grainger. And it also controlled a fan in the restroom area. I think your relay idea is the way to go, if you can find a controller that can work with such a reduced load.
Good luck.

Leviton ODS15-IDW Occupancy Sensor Wall Switch - Line Voltage,

Just buy a new occupancy sensor that is designed to work with electronic ballasts. You will save electricity (sounds like this was the original goal) and magnetic ballasts are going the way of the dinosaur anyway. Sounds like you are a creative problem solver though.

Many new occupancy sensors also include infrared sensors that detect occupancy even if there is no motion. Don't discount all occupancy sensors just because your device was not right for your application.