I had three regular wall switches which operate appliances in this order:

1 Ceiling can lights (replaced with z-wave dimmer switch).

2 Fan lighting

3 Fan on/off (replaced with z-wave fan controller)

At the gang box, there are two incoming (line) wire sets from the breaker and three outbound (load) wire sets. All 5 of the neutrals (white) were twisted and capped. Switch one had two wires connected at the line terminal (one from the breaker and the other jumpered to switch 2 (line). Whats odd is that switch 2 had three wires connected to the line terminal (jumper from switch 1, the other line from the breaker, and another jumper to switch 3).

The two new switches (at position 1 and 3) require neutrals to be connected, so I jumpered each neutral terminal to the other 5 (7 total). Other than that, I kept the same config and things seems to work but I'd like some validation I did it correctly.

It seems redundant that switches 2 and 3 are powered of two lines. Would this cause my ceiling lights (operated by new dimmer switch) to get less current or would everything still draw exactly the current it needs regardless?

  • 2
    You should be able to verify that these switches are connected to two breakers: do you have to turn off both breakers to turn off these lights? If so, you have a dangerous mis-wiring that should be corrected ASAP. If not, then you are mis-understanding the wiring. Either way, I'd recommend that you get a professional electrician in to look at it.
    – DoxyLover
    Feb 15, 2016 at 7:01
  • Are you sure the second "line" is coming from a breaker, and not feeding to another branch of the circuit?
    – Tester101
    Feb 15, 2016 at 13:53
  • One switch on the circuit breaker actually turns off all lights and fan plus another branch (the adjacent hallway).
    – Q-Dawg
    Feb 15, 2016 at 18:34
  • Yes but does the circuit breaker turn off anything else? Like, outlets in the room? Or outlets in the hallway? Feb 16, 2016 at 2:17
  • Yes one breaker kills all lights/outlets in that room and adjacent hallway.
    – Q-Dawg
    Feb 16, 2016 at 16:27

2 Answers 2


If your house was wired by a human electrician then I seriously doubt that your gang box has two supply cables with their neutrals connected together. Surely what you think are two supply cables are actually one supply cable and one unswitched load branch leading to at least some of the outlets. All that jumper wire between the switches is how the hot node ultimately reaches the outlets.

If you are intensely curious you could experiment by disconnecting everything and using a contact meter to find which cable supplies power to the gang box. This is probably the only way you will ever obtain true faith in the fact that you don't have two power cables entering the box.

As for validation, you obviously have the box wired at least as correctly as the original electrician did.

Many electricians recommend using "pigtails" to connect the hot node to all the switches and loads, because then a single connection failure will cause only one load to lose power. However, unless you want to use your house as a laboratory to learn the electrician trade, there's no need to change something that's already working.

  • I think this is the most sane answer. I'll check both inbound to see if they're hot with my contact meter. Provided only one is hot, then I'm good with combining with all the neutrals, correct?
    – Q-Dawg
    Feb 18, 2016 at 2:07
  • @bodhgaya: Yes. Also, additional evidence that all the neutrals should be connected is that that's how it was wired when you found it, and the power to the loads was affected by only one breaker. Feb 18, 2016 at 2:54
  • @bodhgaya: Also, while you have the two unswitched cables separated for testing, check all the outlets. At least some of them should be dead. Feb 18, 2016 at 2:59

If your gang-box is fed from two separate radial circuits, my understanding is that the neutrals should not be combined but should be kept separate.

  • You don't want the possibility that the current from two 20A hots can return via one 20A neutral when there is a fault in the other neutral.

  • You don't want a path by which a circuit can become energised even when the breaker for that circuit is off.

  • You don't want to trip a future GFCI (or equivalent) installed upstream.

  • There's one switch on the circuit breaker that kills all electricity in the room plus an adjacent hallway.
    – Q-Dawg
    Feb 15, 2016 at 18:36
  • The part that I don't understand is the two incoming lines which come into the bottom on the gang box. Are these branches of the same circuit? Why are wall switches 2 and 3 fed from two hots in parallel and would this reduce the power available to switch 1's load? ** On the load side of the gang-box, there are three circuits exiting the top. One of those is the ceiling lights and the other is the fan (since it's the only one with a red). It seems highly likely that the third is the adjacent hallway. Is it essentially needing to be jumpered from one of the other hots?
    – Q-Dawg
    Feb 15, 2016 at 18:51

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