I'm trying to replace a light switch with a new light switch (zwave lightswitch) that requires a 3 wire set up. When I took the old light switch off it was connected with two wires, a black wire and a red wire. There were also two white wires that were just connected to each-other (is that the 3rd wire I need?). This light switch junction seems to be powering an electrical outlet in my room because it is no longer working after I disconnected the light switch. (Could those white wires be what was connecting the outlet?) Does anyone have any ideas as to what I did wrong?

box innards back o' switch instructions

  • Does your Z-wave switch have leads or screw terminals? Jan 16 '17 at 23:24
  • Screw terminals
    – gertzerroz
    Jan 16 '17 at 23:28
  • Are you sure this thing was made for the North American market? Where on this planet are you? Jan 16 '17 at 23:30
  • Is there continuity between the two N terminals on your switch, for that matter? Jan 16 '17 at 23:31
  • This is the wiring setup it requires imgur.com/Pu3nCm6
    – gertzerroz
    Jan 16 '17 at 23:37

Oh, dear. Who did that?

First off, the last person who worked in this box left you a mess to straighten out. You're going to need some 12AWG THHN for pigtailing and a couple of wire nuts to fix this.

  1. Turn the power off to this abomination at the electrical panel.
  2. Use a pair of wire cutters to cut off the splice between the two hot (black) wires and strip the wires back enough for a good junction.
  3. Strip both ends of the pigtail -- one black and one white is best here.
  4. Put one pigtail with the two black wires and wire-nut them together, leaving the other end of this hot pigtail free.
  5. Undo the tape on the white wires and free them up (this may require cutting off the existing junction if it's soldered together)
  6. Put the other pigtail with the two white wires and wire-nut those together.
  7. Wire the black pigtail to the AC Power L terminal, the white pigtail to the AC Power N terminal, and the red wire to the Load L terminal on your switch.
  8. Button things back up and turn the power back on

P.S. this switch doesn't need to be grounded as it has a fixed, nonmetallic faceplate. See NEC 404.9(B) Exception 2 for details.

  • Okay about to head to the hardware store for some 12awg thhn and some wirenuts. Will keep you updated.
    – gertzerroz
    Jan 16 '17 at 23:57
  • Okay I have two pig tails now. So in total I have three free wires.
    – gertzerroz
    Jan 17 '17 at 1:21
  • Right. See Step 7 as to where the pigtails go (assuming the pigtails are color coded to match what they're pigtailed to) Jan 17 '17 at 1:22

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