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Is it considered acceptable practice to use two wirenuts in a situation where it is possible to use only one but may be easier to use two?

I have a three-gang box with six cables coming into it. The person who wired it previously (homeowner, I assume) pigtailed 5 of the 6 black hot wires using a red wire nut. Because he or she still needed to bring a hot to one of the switches, he put two hot wires on a single terminal of one switch (one went to the red wire nut, the other to the switch that didn't connect directly to the pigtail).

I assume this person did this because the wire nut wasn't big enough for all six wires. However, my understanding is that two wires on the same terminal is not a good idea. The best solution, clearly, is get a wire nut that holds all six. As an alternative, I thought of having two pigtails - two wire nuts, each of which would receive three of the six hot wires as well as a wire directly between the two wire nuts (total of four wires into each nut). I realize it makes sense to minimize the number of connections, but I am just curious to know if this is acceptable.

I am new to home wiring, but I hope you understand what I am asking and will let me know what you think of it.

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I assume you are talking about two wires wrapped around a screw on the outside of the device. –  Brad Gilbert Apr 3 '13 at 13:35
    
If the switch has a backstab terminal, you can use that for one of the wires, instead of using the side screw terminal for both. –  Tester101 Apr 3 '13 at 13:48
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3 Answers 3

up vote 4 down vote accepted

Use the right connector

Ideal Industries makes a few different varieties of twist-on wire connectors that can handle 6 conductors. After looking through the UL Listed Combinations (PDF) document, I was able to find 4 such connectors.

If you find yourself needing to connect more than 6 conductors, it's probably time to start looking for something other than a twist-on wire connector. As @Aaron pointed out, you can use a Push-In type connector for up to 8 conductors. You might also want to consider using a Crimp Connector, which can connect 4 to 10 #14 solid conductors (an insulated cover would be required when joining current carrying conductors).

Moving beyond crimp connections, you'll likely have to start looking at terminal blocks, bus bars, design changes, or alternative solutions.

All conductor combinations will vary from manufacturer to manufacturer, check the manufacturers documentation before using any electrical connector

Use devices as connectors

Another option, is to use unused terminals on devices as splice points. For example, you might have a switch with both side and back terminals. Using the back terminal as a splice point, is an acceptable way to extend the circuit. In fact, some industrial grade receptacles (like the Leviton 5252 Series) offer 8 clamp style terminals on the back of the device.

enter image description here

Reduce the number of pigtails

Where multiple devices share a single hot wire, you can reduce the number of wires in a twist-on type connector by using a single extra long pigtail. You'll use the extra long pigtail to connect all the devices, eliminating the need for a single pigtail per device. So you can take the number of required pigtails from 3, down to 1. If you leave the feed hot extra long when originally wiring the circuit, you may be able to eliminate pigtails altogether. To do this:

  1. Remove a bit of the insulation in the middle of the wire.
  2. Wrap the exposed wire around the terminal screw of the first device, and tighten the screw. enter image description here
  3. Remove a bit more insulation further down the wire.
  4. Wrap the exposed wire around the terminal screw of the next device, and tighten the screw. enter image description here
  5. Repeat until all devices are connected.

Once you have all the devices connected in this manner, you can use the end of the wire to feed through to other devices. Simply remove a bit of insulation at the end of the wire, and use a twist-on wire connector to connect this wire to the wires feeding the other devices.

Daisy chain

As for connecting bundles of wires with pigtails. There's no problem doing this, as long as you don't exceed individual connector conductor fill, or overcrowd the box.

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I've chosen this as accepted answer for thoroughness and for directly answering question at the very end in the daisy chain section (saying there's "no problem" with doing what I ask, though there are better options). Incidentally, I didn't realize it was okay to share a long pigtail among several devices. I've seen that done in my house and assumed it was a sketchy shortcut taken by the previous owner. –  susie derkins Apr 4 '13 at 19:31
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If-it-fits-it-ships may not comply with "box fill" section of the NEC. Each connection "consumes" a portion of the box capacity, as do devices. Larger gauge wire count more than smaller. We would need to know box volume and wire gauges, to properly comment. Internal clamps use up volume.

Box fill calculator

2011 NEC relevant section

In general, I think 2 pigtails are more secure and safe than daisy chaining on devices. Pigtails do not count against the volume usage if the wire neither enters or leaves the box.

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You could also use a 6-wire push in connector - the light blue one is the one to look at.

enter image description here

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Thanks for pointing this out as an option. Though I'd be curious to know what you think about the original question. Extending it to this type of connector - what about using two of the yellow connectors instead of one light blue (in a manner similar to what I describe in original question)? –  susie derkins Apr 3 '13 at 11:25
    
@cowguy All things being equal (which of course, they never are), I'd use the one large one instead of 2 smaller ones. But that's my opinion, and it holds as much weight as you want it to. –  Aaron Apr 3 '13 at 15:49
    
Thanks, @Aaron. I've upvoted your answer though wound up accepting tester101's. –  susie derkins Apr 4 '13 at 19:35
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