I had some electrical work done but we were unable to test the lines and now the electrician is gone. To simplify the problem, we have two electrical boxes and two loads. One load (INSIDE LIGHT) will be controlled by the 3-way switches and the other (OUTSIDE LIGHT) by a separate switch. The problem I see, or am not understanding, is the box with the OUTSIDE LIGHT has no actively hot lines yet. Will the 3-way switch in that box have a line that is always hot once wired that I can use?


diagram for standard 3 way switch

UPDATED what I have note 3 wires between boxes

  • Are you OK with foreclosing the ability to have a 4-way switch for these lights, and how many wires are in the cable running between the two switch boxes? – ThreePhaseEel Mar 31 '19 at 20:08
  • Sorry, not sure I understand your question. The lines shown are single black or white lines. I only need to control the inside light by either the boxes. I purchased two 3 way switches for the inside light and one regular switch for the outside light. It appears I only have two lines (one black one white between the boxes) – Hell.Bent Mar 31 '19 at 20:21
  • I updated my image – Hell.Bent Mar 31 '19 at 20:26
  • oops my bad, I actually have 3 cables between boxes.. White, Black and Red. Updated image of what I have. – Hell.Bent Mar 31 '19 at 20:43
  • Is re-running the cable between the two switch-boxes an option? – ThreePhaseEel Mar 31 '19 at 20:59

When you're using old style steam switches, 3-way circuits look like this.

enter image description here

Yellow=travelers, red=switched-hot. Note in this switch position the light will be off.

Notice that there are 2 travelers, and the remote 3-way is lucky if the third wire is neutral. There's no question of bringing always-hot along with the travelers; there simply isn't a 4th conductor in the cable. (And you can't use ground).

Smart switches instead

In this setup, wires 9 and 7/2 are always-hot. Wires 10, 8/1, 6 and 5 are neutral. OK, we got hot and neutral to the far box.

To switch the outside light, you put a plain switch between always-hot 2 and switched-hot 4.

To switch the inside light, we get a 3-way "smart switch". It hooks up as follows:

  • Neutral to 1/5/6.
  • Always-hot (LINE) to 2.
  • Switched-hot (LOAD) to 3.
  • Traveler (if needed) to 11.

Oh wait, you wanted 3-way control. OK, we also put a smart switch "remote" in the other box. It gets:

  • Neutral to 10/8
  • always-hot to 9/7
  • If needed, traveler to 12.

All grounds get spiderwebbed to each other.

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  • Thank you!!! in your explaination doe Leviton 3 way switches qualify as smart switch "remote" ? A plain swtich has two terminals. My 3 ways swtiches have a copper lead on the left and copper lead on the right top and black lead on the right bottom. Sorry, but can you explain how to wire to switches? – Hell.Bent Apr 1 '19 at 13:24
  • You have specs/links to these "smart" switches? – Hell.Bent Apr 1 '19 at 13:31
  • search of Smart 3-way switch pulls up switches with Wifi,, Is that what you mean and what if wifi is down, do they still work? – Hell.Bent Apr 1 '19 at 14:25
  • @Hell.Bent the switch you describe is a plain old steam-era 3-way, and the brass screws are for the travelers as in the first diagram. Some smart switches are able to use a plain switch as a remote, using 1 traveler, which would suffice here. There is a universe of these products and we are not a shopping assistance site. Some use WiFi and others use proprietary protocols or use powerline signaling, Insteon is but one example. Others use 1 traveler, which you happen to have spare! – Harper - Reinstate Monica Apr 1 '19 at 15:31

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