3

I have a 4 switch box that I would like to change the order of. Imagine left to right the switches are in order: ABCD. I'd like them in order: DABC.

When I've worked on a box with multiple switches before, its been 3 wire wiring and I've tied the hot wires together and pig tailed to each switch, like in this video. But when I opened this box, it was a little strange. It 4 wire wiring, and seems to be coming from a double break (240V?) split between the red and black hot wires. Switches A and B (dining room outlet and lights) are on the red wire, and C and D (kitchen lights, basement stairwell light) are on the black wire.

Light switch circuit (red wires at the top are cut off in the box... I'd add wire nuts or tape to those):
Reordering switches is 4 switch box

The breaker:
Reordering switches is 4 switch box

A couple of questions:

  • What's the best way to reorder these switches?

    • I was thinking of just extending the "daisy chain" wires between receptacles so I'd be able to change the order, but otherwise keep this wiring pretty much as-is. My brain just can't handle the switch closest to the kitchen actually controlling the basement stairwell.
  • Are there any safety concerns with this wiring?

  • Why might it have been done like this?

    • My guess was that it might been intended to run these lights and maybe an electric stove (don't have one, and current gas stove is on a separate circuit) on the same 240V circuit, but I'm not sure if having lights and a electric stove on the same circuit is safe anyway?
6
  • 2
    They connected it up as a MWBC circuit. Two hots sharing the neutral instead of the common one hot, one neutral. It saves using an extra neutral wire. Usually used for receptacles/outlets so two will be on separate circuits and can use more power before tripping the breaker.
    – crip659
    Feb 11 at 21:33
  • 1
    If that is an actual diagram of how they are wired up, three way switches used as single switches, then just moving the top black wires over should work. You might need to pigtail/add extra wire if too short. Do not touch if they have three wires(not counting ground) on one switch. Add pictures for the experts.
    – crip659
    Feb 11 at 21:55
  • Be careful not to connect a red wire to black wire. If this is a MWBC then the red and black have 240 V across them. Do you have a VOM meter? Feb 11 at 23:33
  • 2
    @crip659 The switches in the picture are just regular 2-way on/off switches (3-way switches don’t have “off” and “on” markings). The “extra” screw is just the ground terminal.
    – nobody
    Feb 12 at 16:34
  • 2
    Except, @nobody, that this is a drawing and not what's actually there. There is a non-zero chance that the OP grabbed the first nice drawing of a switch he saw and may not have paid attention to that detail. Of course, his post hasn't indicated anything about them being 3-way switches, and the wiring diagram provided indicates they're not, but, it's not proof...
    – FreeMan
    Feb 12 at 17:40

3 Answers 3

6

Are there any safety concerns with this wiring?
Why might it have been done like this?

You have a Multi-Wire Branch Circuit (MWBC). It allows you to run one /3 cable (with one neutral (white), two hots (red & black) and a ground) to simplify wiring. It is, effectively, two circuits in a single cable, saving an extra neutral wire. It requires 2 breakers that must be handle tied so that they're both turned off at the same time to protect workers. Your breakers are properly handle tied, so all is good - this is a perfectly safe wiring set up.

There is absolutely zero intent to run an electric oven/range off of these circuits. Most electric stoves require at least a 30A breaker, not the 15A breaker there, and a 30+A breaker requires much larger wiring than a 15A breaker. Unless you've got at least #10 wire in the wall (that would have an orange or black cable jacket if it was installed in the last 20 or so years), then no, there's no intention of putting a range on this circuit. And yes, putting lighting and an oven on one circuit would be a code violation.

What's the best way to reorder these switches?

To move switch D from the right side of the box to the left:

  • Unscrew the switch from the box.
  • Remove and label the two black wires from it.
  • Unscrew switches A, B & C from the box, leaving them attached to all their wiring and hanging out into the room.
  • Put a small wire nut onto each of the 4 unused red wires leading out of the top of the box. They do not have any power fed into them from this end, but there's no guarantee what someone might do at the other end at some point in the future, so add safety now.
    • If your drawing of the length of these cut wires is remotely accurate, curse the person who cut them that short. There should always be about 6" of wire accessible inside the box so you can wire it. If you can't fit all that wire in, you need a bigger box, not shorter wires.
  • Carefully feed the two black wires from switch D over to the left side of the box where they can connect back to the relocated switch.
    • If there is not enough wire length to reach where they need to go, cut new lengths of wire (14AWG is acceptable since this is a 15A breaker, but you can use 12AWG if you have it handy), wire nut one length to each of the short stubs, and run these new pieces to the left side of the box.
    • If you need to purchase some wire to do this, you might consider picking up a small spool of stranded #14 THHN wire at your local store. Stranded wire is more flexible and will be a bit easier to weave through the box to get to the relocated switch.
  • Connect the wires back to switch D, now relocated to the left side of the box.
  • Carefully feed all the wiring back into the box and attach all 4 switches into the box in their new locations.

NOTE: Your drawing shows 2 wired attached to one screw for switches A & C. Some switches will safely allow this, others won't. If there is a single screw with two wires wrapped around it, this is likely a non-code compliant installation. These wires should be removed from the screw and attached to each other and a third wire with a single wire nut. The other end of that third wire should then be attached to the switch's screw.

If you'll update your original question with a picture of the actual wiring on these two switches, we can help you determine if they're OK as is or need to be rewired.

Please ask a whole new question about the safety/correctness of the wiring on these two switches and include a clear, focused, well-lit picture of the screws on each of the two switches.

2
  • Good observation re two wires. It's common to daisy-chain things in boxes by removing enough insulation along the middle of a wire to make a horseshoe wrap around each screw except the last one. Possibly that's what OP has. Whether that counts as one wire or two for the purpose of complying with the switch's instructions can get a bit metaphysical.
    – jay613
    Feb 12 at 15:24
  • Fair point, @jay613. That's why I asked (twice, even, see comment on OP) for pics of the actual wiring. The OP provided an excellent drawing, but pics are always good, too.
    – FreeMan
    Feb 12 at 15:25
2

Your panel looks full! If the only outlets on both breakers are in the dining room, take the opportunity of working inside this box to free up space by combining underused circuits. You don't need two breakers for dining room outlets and LED lighting for 3 rooms.

Make sure all bulbs served by these switches are LED. Total use will be 0.5 to 2 amps, but you can do the math. Connect all four switches to the black feed wire. Disconnect and cap the red one at both ends. Remove the handle tie. Now you have a spare breaker. Some time in the future, when you need one, it won't be this easy to find.

Now rearrange the switches any way you want.

To answer the "why" question, I can illustrate, you can apply your actual facts: If the kitchen has 8 cans with 100W PARs in them and the dining room has a chandelier with 12 x 40W bulbs, that alone is about enough for a 15A breaker. So the two rooms were fed with two circuits in an efficient way with an MWBC circuit. It saves a wire. With LED lights the equation changes.

2
  • Good idea, great outside the box thinking! (Or is that, inside the box? I'm not sure...)
    – FreeMan
    Feb 12 at 15:43
  • 1
    Disconnect and cap and label the red one at both ends. Mystery cables are no fun.
    – CactusCake
    Feb 12 at 16:05
-1

There's one item that nobody has brought up that concerns me. As shown in your description and picture of your breaker panel, Switch D controls the Basement Light, and it has its own breaker. Switches A, B, and C are the rest of the lights (and a switched receptacle?) which are on a tied two-pole breaker.

That leads me to believe that two separate disconnects (one single pole breaker and one tied-pole breaker) are feeding that box. I can easily envision that the Black wire is on the Basement Lights breaker, the Red wire is on the top tied breaker, and the bottom tied breaker is not connected to anything.

A picture of the wires entering those three breakers would be helpful, in addition to the already requested picture of the switch wiring.

If that's the case, I suggest adding up all of the lights and other outlets being controlled by the circuits that feed that box. If that adds up to less than 12A, I would put them all on a single pole using the black wire on a single (non-tied) 15 amp breaker and use small wire-nuts to cap off both ends of the red wire.

If the NMC cable feeding this box is 12AWG, that changes the above to being less than 16A total and a 20A single pole breaker

If they add up to more than 12A on 14AWG wire (or 16A on 12AWG wire), I would use the tied-breaker, Black on the top pole, Red on the bottom pole. Then each conductor can handle 12A (or 16A). Use this capacity however you see fit in the box. You don't need to split the switches 2+2. You could put 3 switches on Black and 1 switch on Red, for example. With that in mind, as long as you aren't overloading any circuit, you can just wire switch D to the same feed as switch A. I agree with other answers that pigtails should probably be used, instead of the loop through as shown in the diagram. Otherwise, If you purchase a higher grade switch such as https://www.leviton.com/en/products/rs115-2 this model from Leviton, you can use the clamps to safely secure two wires on the Line side.

No matter what you do, you need to confirm that only one breaker (or one TIED breaker) is supplying that box. My understanding of the NEC is that a single disconnect/breaker should de-energize all sources of electricity in a box.

Also, you should use a fill calculator to determine if your box is big enough, though if you're not getting a permit, you won't need to worry about passing an inspection.

YMMV, I am not a lawyer, inspector, or licensed electrician.

3
  • As drawn, both switches C & D are both supplied by the same breaker (note the black wire "jumping" from C to D). All 4 switches are supplied from the same cable which runs back to the handle-tied pair (according to the OP). Since flipping one part of a handle-tied pair will turn off both breakers, there isn't a possibility of turning off one breaker leaving power in the box. In general, this is a valid concern, but not in the OP's case.
    – FreeMan
    Feb 14 at 16:49
  • 2
    My understanding is that a single yoke (or device) must have a single shutoff - that is the basic "MWBC must be handle-tied" rule. But a box can easily have multiple devices with multiple circuits. In fact, I am 100% certain I have that in my house - for example, two of my bathrooms have boxes that originally had a single circuit (actually, one might have had two - not sure...) and electrician added a new circuit for heat/vent/light (which due to the heat needed a dedicated circuit), replacing the single gang box with a double gang. Feb 14 at 17:02
  • 1
    @manassehkatz-Moving2Codidact You're right. I was thinking of the instance like a dishwasher/disposal recepticle.
    – Pants
    Feb 28 at 21:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.