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A receptacle in the garage was falling apart and was not holding plugs firmly. Upon opening the box I noticed the receptacle had 3 whites, 3 blacks and 1 bare ground all from 3 separate cables.

2 whites were connected to 1 screw terminal, same with the black. I've read here that this is against code. I'm in Canada.

Questions before replacing with new receptacle:

  1. If I add a 4th wire to pigtail the whites and blacks thereby connecting only the new 4th white and 4th black under a unique screw each, will the receptacle be compliant?
  2. There is very little length for the whites and blacks, is it OK if I re-use them after cleaning them? I can possibly remove some darkened areas with sand paper or blade.
  3. Is there a limit to the number of wires I can tighten in a wire-nut? I have seen 4 in use in other areas and I have spare wire-nuts the same size.
  4. The receptacle had a single ground wire that was in a wire-nut with 2 more grounds, not 3. The grounds were screwed into the metal box. I expected to see 3 grounds under the wire-nut. Is this OK? I think if the metal box is grounded correctly then subsequent ground wires connected to it will be too.

enter image description here

x---x---x

Here is the end result

I cleaned the old wires till they were shiny and added a 4th wire. The old wires wouldn't extend more than 2" from the metal box so I gently gripped all 4 from their insulation and used a plier to twist the bare ends twice. Then I twisted a wire-nut firmly and covered the opening with electrical tape. I did my best to make sure that no bare wire was exposed but varying lengths made it tricky.

The wire-nut packaging stated MAX: #14×4 so it worked out perfectly.

I did not mess with the grounds, just cleaned the end connected to the old receptacle and reconnected it.

Here is a pic from inside. I connected an outlet tester and it signaled correct wiring. enter image description here

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    Don't put tape on your wire nuts, for goodness sake. If you don't trust your ability to install them correctly, just hire a professional. Nothing says "I'm afraid I did it wrong" like tape inside a device box - and if you don't trust the work, why would you leave it in your house waiting to fail?
    – J...
    May 6, 2022 at 13:19
  • @J... The purpose of the tape is not to secure the wire-nut, its a layer of OCD conductor contact prevention due to varying lengths of wires. 3 of the 4 bare wires were thoroughly tucked under the nut but 1 bare wire was visible (a mm or 2) upon turning the nut over but still within the nut's length. Had I wanted to secure the nut, I would have taped over it. Of the 3 cables, 2 are far back in a recessed box allowing only 2" to cross the metal box. It made it tricky to grab all 4 but I was still able to pre-twist all 4 twice before securing the nut and its not going anywhere.
    – eszed
    May 6, 2022 at 16:54
  • If one wire is too long the correct thing to do is to cut it to an appropriate length before making the splice. Tape is not an acceptable solution. If you don't feel confident using wire nuts, consider using Wagos instead.
    – J...
    May 6, 2022 at 17:33

2 Answers 2

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  1. Yes, pigtailing is fine, and may actually be a requirement since the wires need at least 6" of length and to come at least 3" beyond the face of the box. You're not allowed to do oblige the installer to do finger gymnastics trying to fit all wires onto the receptacle.

  2. Because your wires are so short already, DO NOT CUT THEM. (often, novices cut wires because it's easier, because they do not understand the above rule. They think they have 7" to spare, they actually have 1" to spare.) Straighten and clean them a bit so they're somewhat shiny, steel wool should do nicely, or a Scotchbrite pad (the chef will not want it back lol).

  3. The exact number of wires allowed on a nut is stated in its UL approved documents, and loosely described on the package. Wire nuts are approved for as many as 6 wires. It's best to work in middle of range: if you have four #14 wires to attach, get a nut rated for 2-6 #14 wires, not the one rated for 1-4.

  4. The metal box will automagically carry ground to the receptacle so there is no need for a ground wire to it. Because it has hard flush metal contact with the box, it doesn't even need to be a self-grounding receptacle. But yes, the lack of 3 ground wires for 3 apparent cables deserves investigating further. Keep in mind that "via the shell of non-flexible metal conduit" is a perfectly valid grounding path. And in some cases, flexible conduit.

I am concerned that the cable exiting the top of the box has no physical protection from damage. It needs that up to about 7' high. One way to do that is to extend EMT steel conduit out of the steel box using a standard EMT connector, and sleeve the cable into that. Normally one doesn't sleeve EMT over wires, but in this case it's OK as a damage shield. The wire can just exit the EMT at the top, carefully de-burr that. (don't use a tubing cutter!)

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  • Thanks for the clear responses. I am in the process of getting my tools and the hardware together to get this done in the next hour. I see your concern on the cable being exposed - its supplying a garage opener and is tucked behind a peg board which isn't ideal. We moved into this property 3 months ago and its full of surprises. Every outlet here is backstabbed (i.e. speed wired) AND side wired (under screw terminal) at the same time. One receptacle at a time!
    – eszed
    May 5, 2022 at 20:59
  • @ezsed the peg board should provide physical protection if the cable can freely move back 1.5" beyond the wall surface (i.e can't be pinned by a nail or hook)... I'm concerned with the part outside the peg board. Double using backstabs and screws is "legal"... but backstabs are not particularly reliable. That said, recent science has shown side screws are worse if not properly torqued... torque screwdrivers are now required NEC 110.14. So I am now at sixes and sevens about recommending backstabs. May 5, 2022 at 21:47
  • I've edited my question to add the end result. The peg board does allow that level of freedom. With the outlet replaced, I intend to place a workbench thereby comfortably covering a large area around the unprotected cable. This will have to do for now till I learn more till I stabilize things. Torque screwdrivers, wow. "Screw tightened an additional half-turn or to 12 lb-in". I've always gone by gut and experience - especially when swapping tires. But this is a perfect reason to buy a new tool.
    – eszed
    May 5, 2022 at 23:50
  • @eszed so has everyone else... and fwiw a 1/4" beam-type torque wrench + a bit holder isn't so expensive, and gives the right torque ranges. May 6, 2022 at 1:27
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    Yikes @eszed! While loads of people go by gut instinct on tightening lug nuts, that's how tires fall off. I had a shop put new tires on my van and the gorillas there went by gut. I don't know if they over tightened or under tightened, but I had 3 lugs shear and a front wheel depart company at > 70MPH on the interstate. Not a fun experience. Friends found the wheel 1/4 mile down the road on the other side of the concrete barrier. It's time for a new toy, er tool!
    – FreeMan
    May 6, 2022 at 12:13
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I have to assume you also have these heavy duty outlets available in Canada. They have four holes on the back for wiring which would be a legal, direct replacement for what you have.HD outlet

I think this would be the best option since you're working in a small handy box. Trying to get pigtails and wirenuts all in that small box would be a chore.

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    In the US also, they are called "spec-grade" outlets. This appears to be an "extension box" with another flush-mount box underneath it, so the cubic inches (millimeters?) are indeed available. May 5, 2022 at 19:27
  • Ah, just noticed the hole in the back of the box... Yea, pigtails would be an option if they want to save a trip to buy a better outlet.
    – JPhi1618
    May 5, 2022 at 19:31
  • Yes, these are available and would be an ideal substitute. However, last month I bought a box of Leviton receptacles - the standard TR duplex kind. So I'll use those provided I can work comfortably w/o compromising quality.
    – eszed
    May 5, 2022 at 21:28
  • @Harper-ReinstateUkraine They're also called "spec-grade" in Canada.
    – J...
    May 6, 2022 at 13:17

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