Electrical Question: Using Motion Sensor from One Fixture to Turn on Additional Fixture
Let me clarify this question:
I replaced an outdoor motion-sensing fixture with a new identical one. I wired it identically to the previous one that worked for several years. The previous motion-sensing fixture had a splice at one of the lights. The spliced hot wire, then fed a second fixture. The idea for the setup (not by me) is to have the motion-sensing fixture turn on and then turn on a second fixture. When I tested it a few times, it worked – the motion sensing fixture would light, and then the second fixture would turn on. As I buttoned everything up and tested one final time, there was some flashing at the motion-sensing fixture, then the lights would not work, including the lights at the second fixture. I can hear clicking at the motion sensor, but nothing lights. It appears that the motion sensor is burned out.
What is wrong with this setup? I did not originally wire this, but it seemed to work for a few years.
Thanks in advance.
Replies
I think you are correct.
Sounds like the motion sensor has cooked itself, but maybe not.
Things to check:
1) Did you pinch / cut / short / disconnect a wire when you buttoned up the box?
2) What is the wattage rating of the sensor (switch)? Some are pretty low and that may have contributed to its demise.
Sounds like it is connected approriately, fairly common set up.
Although you say the Hot wire is connected at "one of the lights". Clarified below:
Wiring should be: wall switched hot to 1 of the motion sensor leads, 2nd lead coming out of motion sensor connects to all other hots in the box (light(s) in the same box + hot feed to second fixture. All neutrals present are just nutted together - line in + all light fixture leads + neutral to second fixture.
The fact that it worked properly before you closed the box leads me to believe option # 1 above. The flashing was probably caused by arcing as the wire nut fell off.
Jim
Thanks for your response.
1. I opened the box back up and all connections were still tight, and there is no apparent pinching or anything which would cause a short.
2. The wattage rating of the fixture is 150 watts. I had two 45-watt CFLs at the motion sensored fixture. The second fixture had 2-20 watt CFLs.
The apparent failure when it "flashed" was several flickers at the lightbulb - not the box. I could hear some faint popping. I checked the bulbs after they still work fine in another fixture.
"Wiring should be: wall switched hot to 1 of the motion sensor leads, 2nd lead coming out of motion sensor connects to all other hots in the box (light(s) in the same box + hot feed to second fixture. All neutrals present are just nutted together - line in + all light fixture leads + neutral to second fixture. " Yes, this was the way it is wired.
I can hear clicking of the motion sensor, but nothing lights up. This is the same kind of failure that happened to the old fixture. I can hear the sensor click when I flip the switch on, but the lights do not light.
I've attached a picture showing the wiring at the motion-sensored box.
I don't want to fry another fixture. What is wrong?
I suspect the CFLs are the problem -- the photocell is designed for incandescent. Installing one incandescent lamp alongside the CFLs might prevent failure of the next unit. Or might not.
Actually, the fixture packaging says CFLs are ok...
I'm pretty sure the fixture packaging says I can use PAR38 CFLs, which is what I had in there.
Ok, I drew it out
OK, I drew it out and the only thing I see which is odd is a seemingly redundant set of connections in the red side and neutral side of the circuit.
This is how I understand your configuration:
1) Entering the box for fixture #1 (shown in photo) is a 14/3 cable. Black is hot line in, white is neutral, red is line out to fixture #2, which is also controlled by the motion detector in fixture #1.
Question: Where does fixture # 2 obtain its neutral? It is not being supplied from this box. Perhaps at a wall switch which upplies both this fixture and fixture #2?
2) White neutral from line in is wire-nutted to a factory-made connection which connects line neutral to the motion detector and both lampholdrs in this box. (4 white wires total in this factory-made connection). OK.
3) Red wire from motion detector connects in a wire-nutted connection to the rear lampholder plus a pigtail (3 wires total in this connection). The pigtail connects to a second wire nut which also contains 3 wires - all red - one to the near lampholder, one to the 1st wire nut, one to the 14/3 which continues to the second light fixture.
4) I see the ground wires and they seem to be fine.
Please comment on the accuracy of my photo analysis.
What is present in the photo seems to be fine -- just redundant -- all of the red wires present could be connected in a single wire nut thus eliminating 1 pigtail and 1 wire nut in the box -- but the net effect is the same electrically.
Jim
First open up the fixture (after cutting power) and see if any connections have come loose and see if anything looks burned.
By "flashing" do you mean that the light flashed, or there was arcing inside the fixture or what?
Did you read ALL the directions?
Plenty of CFL's are marked 'don't use on photocells or motion sensors.'
Plenty of motion sensors say 'don't use with CFL's"
It was probably the CFLs....
The packaging said it is ok for PAR38 CFLs, but I think it said 30 watts max. I had CFLs in both fixtures. At the motion sensor fixture, the CFLs were 23 watts, but the ones downstream were 15 watts. Would the combined wattage of 38 watts fry the motion sensor?
With two CFLs you've got two ballasts. The ballasts are an "unpleasant' load for the photocell circuitry -- they tend to produce switching surges. Having two ballasts on a single photocell could indeed be the "straw that broke the camel's back".
Faulty Relay in Motion Sensor
Just concluding this thread:
After talking with the manufacturer of the fixture, they believe it is a faulty relay. They suggested banging on the motion sensor to see if it frees up the relay, or returning the fixture. The fixture has the relay, so CFLs are acceptable to use and the packaging said CFLs are ok. However, I have researched this a little, and CFLs are not really made to turn off/on through a lot of cycles and it is probably better to use a different bulb. I'll probably just get a new fixture and use the recommended bulb for the light which is a PAR38 halogen.