I'm currently planning on replacing a 3-way switch for the lights in my room with a motion-sensing one.

Currently, the setup is as follows (refer to photos below):

  1. On the switch with incoming power, there is a hot wire (wire "Ch" in the photo below) and two traveller wires (Ct1 and Ct2).
  2. On the second switch, there are the two traveller wires (Mt1 and Mt2), as well as a hot wire that's white for some reason (wire "Mh" in the photo below)

Old Companion Switch 1

Old Companion Switch 2

Old Main Switch 1

I want to replace the switches above with a new motion-sensing switch and it's related companion switch.

Would it be correct for me to do the following:

New Companion Switch (Lutron MA-AS)

  1. Add the live wire ("Ch") and the two traveller wires ("Ct1", "Ct2") to the respective screws based on the instructions provided by the companion switch (Ch --> black screw; Ct1 and Ct2 to brass and blue screws);
  2. Remove the green cover from the green ground wire and connect it directly to the metal box;

New Main Motion Sensing Switch (Lutron MS-OPS5MH)

  1. Pigtail the red and the black wires to the appropriate traveller wires based on the instructions from the new switch (the two wires to the first black wire and to the blue wire);
  2. Pigtail the white hot wire (wire "Mh" above) to the "hot wire" based on the instructions from the new switch (this white hot wire to the second black wire on the new switch);
  3. Pigtail the switch's white wire to the bundle of neutral wires already in the electrical box;
  4. Connect the bare copper ground wire to the metal box

New Companion Switch

New Main Motion Switch

I wanted to run it by y'all before potentially setting my house on fire and killing myself and my family.


  • Please indicate the make/model of the new switches. You might even want to include a link to the installation instructions so people don't have to look them up.
    – FreeMan
    Oct 25, 2021 at 18:18
  • Hi @FreeMan - added the model #s and the link to installation instructions - sorry for the confusion!
    – leer317
    Oct 25, 2021 at 18:54
  • It looks a lot to me like the white wire is a pigtail to a wire nut inside the same box. If so, they chose white because it was just the first piece of scrap wire they laid hands on. Can you confirm? Oct 25, 2021 at 23:31
  • Yeah - the white wire was pigtailed to the yellow wire nut in the same box!
    – leer317
    Oct 25, 2021 at 23:45

1 Answer 1


Self-answer: I installed it as per above and it seems to be working properly! Per “Harper - Reinstate Monica”, it appears that the white wire was indeed a scrap wire instead of a neutral wire.

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