Wiring – Help with wiring new dimmer switches

dimmer-switchwiring

I recently moved into a new house and am trying to replace a couple of dimmer switches but it's proving more complicated than I'd expected.

I have a fairly long living room which is sort of divided into into 2 sides, let's call them A and B.
Each side has 4 recessed pot lights (so 8 lights in total), and each side has a 2 gang box.
Each box has a 3-way switch on the left hand side, (can turn on/off all 8 lights), and a dimmer switch on the right hand side (can dim only the 4 lights on that side of the room)

My goal is to remove all existing switches and install a smart dimmer (Leviton DH6HD-1BZ) on one side of the room, and the matching remote (Leviton DD00R-DLZ) on the other side, and then finish each box with a 2-gang 1-hole plate.

Here are the wiring instructions for the smart dimmer:
http://www.homedepot.com/catalog/pdfImages/3e/3e474cd2-a567-4471-a400-3e21fd978b0b.pdf
(see step 4b for wiring with the matching remote)

My problem is that there are so many black wires in each box that I'm having trouble identifying which ones need connecting to the new dimmers, or which ones need connecting to each other in order to complete the circuit!

Here’s a crude diagram of how everything was wired up initially:

enter image description here

Am I right in thinking that I can just remove everything, then install the matching dimmer where the 3-way currently is on side ‘B’ of the room (using connections A1, B2, C3 in my diagram), and then install the smart dimmer where the 3-way is on side ‘A’ (using connections 10H, 12F, 13G) and then the fourth connection (traveler?) into the smart dimmer should be 16? and leave 14 and 18 together, right?

Any help/advise would be very appreciated! Thanks!

Best Answer

First off -- nice wiring diagram!

To answer your actual question, though:

Putting the dimmer in box A and the remote in box B is indeed your best plan -- it's possible to do it the other way around, although that is slightly outside the scope of this answer. To do that, you'll need to make the following connections (with the breaker off, of course!):

  • Dimmer BK pigtailed to the junction of 14 and 18
  • Dimmer YL/RD connected to 13
  • Wire 12 connected to the 11/17/15 junction, and dimmer WH pigtailed to that same junction (you may need to upsize the wire nut a bit here)
  • Dimmer RD pigtailed to 10 and 16 (which are joined together now)
  • Dimmer GND (green) pigtailed to all other grounds in box A -- if there aren't any bare or green wires in the box, do not connect anything to this terminal
  • Remote BK connected to 3
  • Remote YL/RD connected to 1
  • Remote WH connected to 2
  • Remote GND (greeen) pigtailed to all other grounds in box B -- if there aren't any bare or green wires in the box, do not connect anything to this terminal
  • The existing 5/6/8 junction must remain intact here (the 12 to 2 white wire provides neutral to the dimmer remote itself to avoid a NEC 300.3(B)/310.10(H) violation due to wayward neutral current from the remote)
  • 7 and 9 are nutted together to power the lamps on B side from the dimmer feed coming from the A side (the Leviton smart-dimmers need to be on the load side of a multi-way setup)
  • Finally, make sure 4 is capped off with a wirenut as we have no clue where it leads. Connecting it to the hot in box B would be a 300.3(B)/310.10(H) violation due to its power coming into the box on the 14 to 3 wire and its neutral returning back from the box on the wire that connects to 11 in box A, which is either 6 or 8. Connecting it to the dimmed hot in box B would also risk a Code violation if it leads to anything that's not a light fixture, as 404.14 prohibits connecting a dimmer to any load, other than a permanently installed incandescent fixture, that it's not rated for, and 406.15 prohibits dimming standard receptacles.
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