How to wire up a RS-150BA-N Vacancy Sensor Switch with Nightlight and Manual On/Off

If you only have one black and one white, you won't be able to put your new sensor here.

The black is always on and is the power. The white is what is switched on and off and is the load. You're missing the needed neutral. You should also have a bare copper wire, which is ground.

This is because the switch comes AFTER the light in your circuit instead of before it.

Thank you Noozer for your volunteer help; I greatly appreciate the advice. I'm a bit confused. If a circuit is a complete loop, why would it matter if the switch is before or after the load?

Note: I do understand that the black wire in the wall is the hot (incoming

120vac) wire and that the white wires in the wall are the neutral (outgoing, supposedly near 0vac) wires which go into the ground at every fifth telephone pole or so. And I do understand that the bare wire (green on the switch) is grounded to my water pipes and does not carry current normally. But I have no idea what this red (load) wire is supposed to do.

In looking again, there is a bare copper wire inside the box as you noted, so you know your stuff. But there certainly isn't a red wire.

While I understand your basic premise that I can't use the switch because I don't have three wires in the box (black, white, red) to connect the three wires on the switch (black, white, red), I still don't understand why this circuit is different.

If it helps, I did put the switch on another wall outlet which did have a black, a set of whites crimped together, and a red ... and the Legrand "WattStopper RS-150BA-N Vacancy Sensor Switch with Nightlight and Manual on/off" wall switch worked fine.

Can you explain why some of my wall boxes have only a black and a white and ground while other boxes have a black, a set of whites crimped together, and a red wire?

It is not unusual for a switch to simply be connected to the "hot" and the "load" (the other side of the lamp from the neutral). So then you will only have the "hot" and the outgoing wire to the lamp fixture, thus there is no neutral to power your electronics in the sensor.

The actual feed 120 volt, for the circuit can be run to the switch, as it was where you found the two white wires crimped together, or the feed can be run to the light fixture. If it's run to the light fixture, the neutral wires don't need to be run down to the switch, so only the "hot" wire is run down and back from the switch. Not all occupancy sensor switches require a neutral to operate. Some will work with only the two wires, although I'm not sure they would work with a fluorescent fixture

If the switch was wired according to generally accepted practices, the white wire is probably the hot and the black wire is the load. A simple bulb and pigtail socket can confirm this. Check each wire to ground. You need a neutral to operate the WattStopper just like you need a neutral to operate the light fixture. You do not have a neutral so you cannot use the WattStopper to replace this switch. The alternative is to rewire the switch with a three wire cable from the ceiling light.

In this case the original installer found it easiest to just run a switch leg to the wall switch from the ceiling light to interrupt current going to the light fixture. If you were to remove the light fixture and look in the ceiling box you may see that the white wire from the switch is connected to a black hot wire and tucked into the back of the box. You should also see the black wire from the switch connected to the light fixture and a white neutral wire connected to the light fixture as well.

Other wall boxes may have more wires in them because the original installer chose to use them as junction boxes to make splices so that other outlets, switches, or lights can be fed from those particular locations. Either way is acceptable. Lately I have been running my feeds through the switch box because of instances such as yours when a neutral is required.

Going by the NEC, the white is the feed to the switch, and the black feeds the load. You are not allowed to use a white wire to carry the "hot" at the point of consumption.

Your new sensor switch needs a hot and a neutral to power the sensor circuitry in the switch. That takes 2 wires. In addition, it switches a load on/off, so you need an additional wire from the switch to the load. Finally, it needs a fourth wire if it is to be grounded, as it should be.

Ignoring ground, you have only 2 wires, so your switch cannot work in that location, unless you do some rewiring. Perhaps a diagram will make this clear:

EXISTING CIRCUIT

Load J-box Switch box ---------- ---------- Hot -----|----------|-------------|-----+ | | | | | | | | | |> | | | | | | | Neutral -|--+ +--|-------------|--------+ | | | | | | | ---------- ---------- | | Light Fixture

Note that there is no neutral wire inside the switch junction box. Therefore, your sensor switch does not get the power it needs. Here's a diagram of what the wiring would need to look like for your sensor switch to work:

Load J-box Switch box ---------- ------------- Hot -----|----------|-------------|-----+--+ | | | | | | | | +-------|-------------|-CKT-+ |> | | | | | | | | Neutral -|--+ +--|-------------|-----------+ | | | | | | | ---------- ------------- | | Light Fixture

With the wiring above, the sensor circuit (CKT in the diagram) gets the hot and neutral connections it needs to operate.

There is another way that wiring can run. It does not apply to your situation (because your power feed is to the junction box with the light fixture), but I'll diagram it for reference:

Load J-box Switch box ---------- ---------- | | | +--------|--- Hot | | | | | | | | |> | | | | | | | | +-------|-------------|----+ | | | | | | | | +--|-------------|----------|--- Neutral | | | | | | ---------- ---------- | | Light Fixture

Note that in the diagram above 2 cables, each containing a white wire, a black wire and a ground wire (ground wire not shown) run into the junction box where the switch is located. (In your case, you have only 1 cable.) Power feed is to the switch box in the diagram above, not to the fixture box as is the case with your existing wiring.

Ed

On my way to work today, I finally got through to WattStopper Legrand at

+1-888-817-0571. The support guy answered immediately. Twice (I lost the call when I moved from one cell to another).

The guy looked up the spec for the "RS-150BA-N Vacancy Sensor Switch with Nightlight and Manual 1. Generally when you have a white/black/bare in the wall box, the white is the HOT wire (not the black!).

1. The switch will work with two wires but the night light won't light.
2. It should work fine with flourescent or incandescent, even with just two of the four wires on the switch hooked up (white/black/red/green).

He specifically said to wire in this order:

1. Tie the ground (bare) wire in the wall to the green in the switch.
2. Tie the load (black) in the wall to the white wire in the switch
3. Tie the hot (white) in the wall to the black wire in the switch

I'll try it tonight when I get back from work. He said this isn't the optimal confuration but only the night-light LED won't work.

It's too hard to connect the green (ground) wire to the bare wire as the bare wire doesn't have any connection anywhere in the box. Do you think that will matter if I don't connect the green wire (I think it's optional)?

Thanks for all your wonderful volunteer help!

At an outlet box it is generally exactly the opposite. Neutral is white. Hot is black. Ground is green or bare. In a switch box the white is often the unswitched hot and the black is switched hot though some people reverse that.

That depends. In switches in my home the night light is wired across the switch. If the light is on the night light is off and vice versa. However, if the bulb goes out the night light doesn't work either because the circuit is open.

No doubt the switches you're using are of a different design.