Wiring two motion sensors in parallel

Old 10-06-15, 12:36 PM
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Wiring two motion sensors in parallel

I have a walkway around my house that leads from my driveway, around the house to a basement entrance. I would like to have one set of lights illuminating the walkway that will turn on when someone walks from the driveway towards the back, as well as when someone walks from the back to the driveway (i.e. NOT a 3-way switch set-up). This means I would need 2 motion sensors wired in parallel (1 at the front and 1 at the back), that switch on the same set of lights.

My question is how do I wire these correctly? I've found this page that outlines how to do it and it seems pretty simple, but I want to confirm that it's correct:

How To Wire 2 Or More Motion Sensors To The Same Lights

I could be making this more complicated in my head than it is, but my concern is when someone walks around the house, one switch will turn on the lights and as they walk past the other switch it will also turn on, meaning that both switches will be active and supplying power to the string of lights. I'm no electrician, but seems like that could cause problems??? Or is that just an issue if you wire the switches at each end of the string of lights, as oppose to at the beginning of the string as shown on the webpage?

Any input would be appreciated!


Last edited by cappyriz; 10-06-15 at 12:51 PM.
Old 10-06-15, 02:23 PM
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In order to use a second motion sensor....... you would need to run a piece of three wire cable between them so that you had them both connected in parallel. You must connect red to red, white to white and black to black.
Old 10-06-15, 02:27 PM
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As long as you wire it as shown, with the same power source circuit feeding all the motion sensors, it will be ok. Do not try to use two different circuits to supply the power for the two sensors.
Old 10-13-15, 03:04 PM
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I have been doing this since 1994. As long as the motion sensors have relays in them (they click when they turn on or off), they can be interconnected.

I ran a 3-wire cable between the two 2-lamp motion detector fixtures, with power coming in to one of the boxes. I connected the live and neutral wires normally to the white and black wiring. Done this way, the motion detectors work independently. Now undo the wire nut connecting the motion detector to the light (but not to power) at each end, and add the red wire to these connections. Now either motion detector works both lights.

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