Bypass Motion Sensor - Add Switch to Lights?

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Old 05-21-20, 12:43 AM
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Bypass Motion Sensor - Add Switch to Lights?

Hi. Apologies in advance to anyone double-reading this post, which I also shared on another site.

I'm looking to add motion sensors to 2 or 3 floodlights. I want to be able to use a switch to bypass the sensors and leave the lights on. (Please note that I'm not interested in the ON-OFF-ON type of action.) As the attached diagram shows, I believe I'll have to run a black wire directly from the outlet (source) to the sensors' live terminals (to always keep them powered), and then a separate black wire from the switch to the floodlights themselves. (I left out ground to keep things simple.) Could you please let me know if this will work?

My concern is that there will be 2 live wires connected to the floodlights (black from the switch, red from the sensor). I don't know if this "double charging" the light is bad, and also how it would affect the sensor's SL terminal. Thanks for the help.

 
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Old 05-21-20, 10:05 AM
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The majority of light sensors are relay controlled so what you want to do is ok.
Just keep in mind that either sensor will now trigger both lights at the same time.

You would have to use a two pole switch to keep the sensors isolated.
 
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Old 05-22-20, 04:30 PM
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PJmax, thank you for the reply.

I would actually like for one sensor to automatically activate both lights, so thanks for letting me know it'll work this way. However, I just realized that this would happen because I assume the black (L) from the light is feeding down and up to the second light? If that's the case, isn't there "excess" current also going back to the light switch and wouldn't that be a problem?

Also, any issue with blue wire being used instead of the black (going from the light switch)? Dumb question but I've wondered why white wires are taped (to indicate hot) when there are other wire colors to choose from (like red, yellow).
 
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Old 05-22-20, 04:39 PM
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When using cable there are basically two choices....
#XX-2 w/ground which is white and black.
#xx-3 w/ground which uses white, black and and red.
#xx-4 w/ground is not easily found but would be white, black, red and blue.

Any time the white is used as a hot for a switch loop it gets taped a color.

You're mentioning colors that are not found in a cable which means you have conduit.
In conduit.... white is neutral and almost every other color can be hot. (except green is always ground)

There is no problem with one sensor tripping two lights. Most sensors are rated for at least 300 ,watts.
 
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Old 05-24-20, 02:13 PM
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PJmax, thanks again for the response. I have one more question: if I were to use a security light -- with the motion sensor built in -- how would the wiring go in my diagram? I imagine the security light would only have the standard 3 wires (black, white, green), so I'm not sure how I'd connect the black from the light switch, since the live terminal for the security light already has the direct black feed from the outlet (for the constant power)?
 
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Old 05-24-20, 02:15 PM
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The black from your bypass switch would have to go to the red wire wire of the sensor.
 
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Old 05-25-20, 10:57 AM
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PJmax, I'm not sure if lights with a built-in sensor would allow easy access to the red, but I haven't checked it out yet. I see what you're saying, though.

Thanks again...again
 
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Old 05-25-20, 11:31 AM
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Access to the wiring between the sensor and the lamp is different on every fixture but if there is a white and black wire for power...... then you could add a red one too. Usually the motion sensors are designed to be replaceable.
 
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Old 05-27-20, 01:14 AM
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Thank you, PJmax. Appreciate the help.
 
 

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