I have a single on/off switch controlling a single light. I’ve checked carefully, and have ONLY one 3-wire Romex with black, white, and bare copper ground. (No white neutral wire hidden in box.) Am I correct (as the box says) that I CANNOT install an Insteon 2477S? Is there a different Insteon switch that would work? (Calif. house built in 1988.)

  • Black is the power, white is the neutral and bare is the ground. Why do you think there should be another white?
    – Alaska Man
    Feb 24 '19 at 18:51
  • Have answered own question. No, it will not work, but Insteon 2-wire dimmer should, or can use Insteon bulb, leaving switch always on.
    – Derek
    Feb 24 '19 at 19:12
  • Alaska man: Thanks. Smarthome says “While it is true that the ground wire and the neutral wires connect to the same place in your circuit panel, it is NOT acceptable by building and electrical codes to use the ground wire in this manner.” the switch says it requires a neutral.
    – Derek
    Feb 24 '19 at 19:15
  • If there is an answer to your question then you should post is as an answer and choose as correct so the question does not stay open and keep getting bumped up. Give a detailed answer so others will understand.
    – Alaska Man
    Feb 24 '19 at 19:16
  • @Harper I did not think enough before posting. Not the first time.
    – Alaska Man
    Feb 24 '19 at 19:27

You can't. Neutral is not available in that box.

This is a switch loop, and currently white and black are always-hot and switched-hot. The proper method is to use white as always-hot, to make it more apparent that it is not a neutral (i.e. it's always hot).

Your best bet is to go up into the lamp box and re-task the black and white wires to be always-hot and neutral (white must become the neutral, so make black always-hot). The switch's red wire goes to nothing at all. Then, obtain an Insteon inline module and place that up in the ceiling rose of the lamp. It will connect to always-hot, neutral and switched-hot to the lamp. (the lamp's other wire goes to neutral, of course). Then you pair the module to the switch.

It may also be possible to obtain LED bulbs with the module built into the bulb.

  • Thank you. Very clear explanation. I’ve learned that an Insteon 2-wire dimmer switch will also work, which is cheaper than the three leds I would need to relapse the fixture, and also cheaper than an online module, though either of those solutions would also work.
    – Derek
    Feb 24 '19 at 21:22
  • I have to admit that I would need a detailed explanation on these new switches. If one would repurpose the white wire of the switch loop to a neutral to connect some smart switch that requires a neutral, then that switch would have to wirelessly communicate with a module in the ceiling box, right? So one needs two devices a sender and a receiver/switch. But how would an "Insteon 2-wire switch" work? I am aware of smart switches that are powered without a neutral by a trickle current through the load, so low that the light is not perceptibly lit. Is that the "2-wire switch"? Feb 24 '19 at 23:45

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