Hoping to get a concrete answer on this. I’m trying to wire a replacement motion light sensor (just the sensor element that is usually attached to a motion sensor light) into the existing circuit that powers my exterior lights. I’d like to wire it up like a switch (ie it senses light and opens the circuit). The replacement head has three leads coming out of it, white (neutral), black (hot) and red (a second hot, I assume). The question I have is how do I wire this thing like a switch? Do I have the inbound hot going to the black lead, while the red is the outbound hot? If this thing is, in fact, a simple switch, why the neutral wire? Also, is there a risk of burning the element out if I test different permutations (ie white is the outbound lead from the switch). Any help that you all could provide would be much appreciated!!!
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Listeners write in about haunted pipes and building-science tomes, and they ask questions about roof venting and roof leaks.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Combine all neutrals, black is incoming hot line. Red is hot for the load side. (Generally speaking, of course) The thing needs a neutral because it, in and of itself, is not a switch. it is an electrical device that requires current to operate. How is it going to sense someone there and turn the lights on unless it is itself drawing some power? hence the need for the neutral.
Thanks for the advice! It worked perfectly!
The second post is correct. Also, Don't try different combinations of wires. You'll probably break it. Black is hot. White is neutral. Red is output to light. My experience with those things is not good. They don't work well and don't last long. If anybody can recommend a really good brand of industrial-quality motion sensor, I'd love to hear about it. Something that lasts 5 years or more and really works. Summer and winter. No cheap plastic. I can't find anything around here except inexpensive stuff. Not worth the effort of putting it in. Happy to pay a fair price for something reliable.
It sounds like you are over your head here and maybe sould not be doing this.
"I'm trying to wire a replacement motion light sensor (just the sensor element that is usually attached to a motion sensor light)"
"I'd like to wire it up like a switch (ie it senses light and opens the circuit)."
A motion sensor senses motion by by detecting the movement of infra-red energy across the lense. It has nothing to do with light. (However, some units have a feature in them that inhibit there operations during the day).
Common motion sensors come in 2 types. Ones that are built into the light fixtures, ie a motion sensor light, and those are standalone and designed to operate ordinary light fixtures. You would not hook up a standalone motion sensor control to a motion sensor light.
"he replacement head has three leads coming out of it, white (neutral), black (hot) and red (a second hot, I assume)."
Not there is not "second hot". I have never seen one that does not have instructions with it and also eithe a lable on the back of the unit or tags on each lead.
No guarantees, but most likely black is hot, white is neutral, and red is LOAD or SWITCHED HOT.
"The question I have is how do I wire this thing like a switch? "
Some switches are wired with a switch leg and don't have a neutral connection in the box. In that case you can't use one of these.
If the switch is wired with power coming into the box and then to the load you need to identifiy which is the supply (hot) and which is the load connections.
You may run into the problem that the existing switch box (or wherever you're installing the sensor) has only two wires (other than ground). In that case you're sorta hosed.