Three-Way Switch Wiring
 

The instructions (Chinglish) for installing my new motion-sensing switch in a three-way circuit suggest "Determine which electrical box as a LOAD connection". The box where I would prefer to install this motion-sensing switch has two blacks, a red and a ground. Can anybody determine, from that wiring, whether this is the LOAD or the LINE box in a three-way circuit? (I realize I could call a qualified electrician, so please don't suggest the obvious.) I was unaware there was a difference, but this switch, in Chinglish, seems to say that it can apparently only be installed in the LOAD side and that box is blocked by our dryer so it would be ineffective if installed there. Thanks for the help.

3 way
 

Disconnect the red wire & if it is not hot it is the load wire.
Please turnoff the breaker first and then turn it back on for the test.

Try youtube for installation help.

:bigbow:

I would say the red being Hot (coming from panel) or Load (coming to light) and the other two black wires as travelers (jumping from switch to switch). I can do a drawing and post it here if you like?

As an electrician in a former life, I can guarantee that your motion-sensing switch will not work in a 3-way circuit, unless it says on the box it's designed for a 3-way circuit.

Two of the three wires you are seeing are called "travelers". The red one is probably one of them. A good electrician will have twisted them together. Either one or the other will carry current, depending on the setting of the two switches in the circuit.

The other wire is either a "hot" (line) or a "switch-leg" (load). If you look at the 3-way switch you removed, you will see that two of the screws are silver and the other is brass. The brass screw is attached to the hot or switchleg, depending on which end of the circuit the switch is on. The travelers are attached to the silver screws.

If your motion-detecting switch doesn't have three screws like that (or three wires with appropriate labels), it is not a three-way switch, and will not work in the circuit.

The only way to determine the hot wire is with a circuit tester, with the power on, which is not something I would recommend for a non-electrician.

Get an electrician. If you do it wrong, or have the wrong type of connection, what if you have a fire? If it were me, I wouldn’t chance it.

Installing a switch and you have no idea about the wiring. Yet you won't call an electrician. Fill in the blank: There's never a shortage of "blank" in The Villages.

3 way
 

An easier way is to turn the light off by one of the switches and then the red wire that is not hot is the switch leg and not the feed

A bit of clarification would be in order- Is this a motion detector for perhaps an outdoor spotlight?
or is this a passive (no contact) light switch?


I agree with Shadywood.
Motion detectors only get used on circuits with only one switch, not 3-way circuits.
I have one out back, turn the switch on, the detector is working. Switch off - detector is offline.

Almost as much fun as installing a 4-way switch in an existing circuit in a hot attic.

The online description of the switch specifically says it is for a 3-way circuit (I'm not quite that dense) BUT it doesn't say that it can only be installed in the "LOAD" box and therein lies my confusion. Your post mentions which "end" of the circuit the box is on and that's what I am trying to clarify. Apparently one end is considered the "Line" end and the other is considered the "Load" end. From what I've read, it appears to me that the box I would like to install it in is a "LINE" box (in their language). This is based on its proximity to the breaker panel plus I don't see enough wires for this box to feed the light being controlled. I have ordered a three-way motion-sensing switch from a different manufacturer to see if it has such a restriction. I understand single pole, double throw switches but it is the definitions (by the switch maker) that confused me. Thanks to all who posted helpful replies.

Hire someone who knows what they are doing. So you don’t get dead!!!!

Hire an electrician. Power kills.

Ditto, hire an electrician.