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Trying to rig up a motion detector switch in the shop so the lights come on no matter which of three doors I come in from and stay on as long as I move around in the shop every five minutes. The existing (and only) switch was on the wall next to one door and cut the live lead to the lights when in the off position. I extended the wires from that box to a handi box near the ceiling centered on the longest wall and installed a residential motion switch. It works, sort of, but one door is out of range so you have to take three or four steps into the shop before it turns on. The switch is also too far away from part of the grinding bench so I can be grinding or polishing in that area and the lights go off even though I have direct line of sight to the detector.

Picked up a replacement motion sensor for outdoor security lights because it has 270 degree rather than 180 degree detection radius and reaches out to 100 feet, but wiring it has me stumped. The outdoor motion sensor has four wires; black, white, red and ground. The wiring diagram shows a standard hot/neutral/ground box on which the switch black is wired to black from the box, switch white to box white to light white, switch red to light black, and switch ground to box ground and light ground. Since all I have in my box are two blacks and a ground I'm stumped. Tried capping the switch white, hooking the switch black to one box black, the switch red to the other black, and ground to ground, but no joy.

Am I just out of luck or is there a way to jump one of the leads from the switch to make the detector act like a normal on/off switch?
 

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You need the neutral (white wire ) hooked up on the new motion switch or it won't work.
If you only have 2 wires in the switch box plus the ground then the neutral wire is up in a j-box behind the light. Is it wired in conduit of flex?
Can you pull another wire down to the switch box?
GW
 

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White (neutral) and the ground (bare wire or green) will both run to the same grounding block in the service panel if that helps you at all.
Can you post a picture of the wiring schematic for the motion detector?
CaptMax
 

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Is power routed to the switch, or directly to the light with a switch leg down to the switch? If the switch has only a switch leg to it it is using both the black and white wires to break the power flow to the light.

And yes you need the white neutral wire connected properly. Think of electricity as flowing through a garden hose, if you only have the black (hot) connected and not the neutral (white) then the electricity cannot flow allowing the light to work.

I would suspect on you motion sensor your red and black are your switch wires so you need to run the black hot to the black on the motion detector then the red out to the black feeding your light.

I reread your post if the light switch box has the 2 blacks then you have a switch leg there, power is to the light the switch leg allows you to break the flow. If you have 2 blacks in the light box you have old wiring from the 1940s, there might be a small bare ground hidden in the wrapped part of the wire, it was suppossed to be screwed connecting the metal outlet/switch boxes but lots of guys would just cut those off and not bother. You need to figure in that case which is the neutral. You have a 50/50 chance of getting it right. Wire one as if it the hot and the other as the neutral. If it doesnt work then reverse it and try again. Even on 1940s wire there were indications which was neutral but age and grime, electrical tape goo can make it hard to see. You might consider pulling a fresh wire and bringing it up to code. Sent you a PM.
 

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Discussion Starter #5
As near as I can tell power goes directly to the lights with one switch leg. I was hoping to avoid it, but it looks like the best option is to cut out the switch leg and route power for the lights to the box for the motion sensor, then on through the sensor to the lights. Then I can follow the installation schematic for the sensor exactly. The lights are on their own circuit and breaker and all the old wiring is buried in drywall and insulation, so I will just cut the old feed then tap in at the breaker box and run surface conduit to the sensor box. Then surface conduit on to the first light (of five). Fortunately I know which one that is.

Funny how a twenty dollar "fix" can turn into a two hundred dollar job. :confused:

Thanks for all the help, guys. And thanks for the PM from GGG. I'll keep you in mind if I get stumped again.
 

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Yikes.
It would help to know a few more things.

First off .
What type of electrical wiring is in your building?
Specifically from the switch box to the light fixture.
is that wire ( 2 blacks and a green) run in conduit or flex ? that's about the only way your going to have 2 blacks and a green in a box without a white wire.
If it's run in Romex ( normally yellow or white plastic jacket over a black and white wire and bare copper wire)
or MC or BX Normally a black and white and green wire inside a metal jacket.
If it's in flex or conduit you can pull an extra wire down to the sensor/ switch.

The black wire from the new sensor needs to be connected to a non switched hot wire.
The red wire from the sensor needs to connect to the black wire on the light fixture/ fixtures you are trying to operate.
The white wire from the sensor needs to connect to the white wire on the light fixture as well as a white neutral wire from the panel board.

Neutral and ground are two separate things you should never connect them together except at the main electrical service feeding your house.
Any other panel boards fed from the main electrical service are called sub panels and they require the neutrals and grounds be isolated from each other.

A ground wire should never carry any current or electricity on it it is for your safety.
A neutral wire (white wire ) is the return path for the hot wire yes , it eventually goes to ground but back at the main panel.
GW
 

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Discussion Starter #8
ok looks like you got it figured out.

GW

That's the hope. Picked up the materials this morning. Will work on it Monday. If you see a flash of bright light on the western horizon sometime Monday morning you'll know things didn't go as planned. :D
 

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Hah! All else fails, rip out the old stuff and do it to code. I now can turn on the shop lights simply by opening any of the three entry doors. Had to turn down the gain on the sensor a bit when I walked past outside the door that has a half window on my way from the lawn shed to the house and the lights in the shop came on. Pretty impressive, but we have deer, skunks and the neighbors' dogs that wander through the yard and past that same door. No way am I jumping out of bed, grabbing a .45 and clearing the shop two or three times a night because the lights came on - again.

Speaking of deer, we seem to have been adopted by a small group of six. Have seem them on or near the property four of the last seven mornings. When The Frau got up one morning last week and opened the levelor blinds in the laundry room she found herself face to face with a doe that had wandered up on the porch and was about a foot from the window. The deer didn't scream like a little girl but they both bolted opposite directions at high rates of speed. I was standing at the kitchen window when a screech rocked the laundry room and a doe rocketed by outside on her way to the back fence. The funny part was that the deer all stood in a group on a hillside just past the fence looking back at the house, then at each other. I swear that doe was telling her companions all about it. I know I got the story two or three times. :D
 

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Hmmm, no sparky sparky? Nice job. When dealing with wiring that old sometimes its worth the effort to put in new. Insurance likes it, and makes selling a property easier with new stuff.
 
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