I have three receptacles boxes with burnt aluminum wiring. I,m going to use three port alumiconn conectors to repair outlet and join copper pigtail with two aluminum wires. I will be using one for hot,one for neutral, and one for ground. What number do I assign each connector for box cubic fill. Hopefully electrical boxes will be big enough after adding all numbers for wires and receptacle and connectors. I have incoming romex, traveling romex to next box down line,receptacle and three alumiconn connectors.

  • Are these plastic or metal boxes? Are you OK with receptacle boxes that protrude from the wall? Feb 23, 2018 at 4:41
  • they are fiber glass boxes I believe. thanks for the idea of box extenders Feb 23, 2018 at 4:59
  • Can you use CO-ALR receptacles? Is there a reason you cannot? Feb 23, 2018 at 9:43
  • Reason I ask is for the price of 9 Alumiconns, you could buy 3 CO-ALR receptacles and an AFCI breaker. The real problem is arcing. Improving wiring methods helps reduce arcing, but an AFCI stops it cold. Feb 24, 2018 at 4:11

1 Answer 1


Splicing devices don't have a box fill allowance, even though they may be chunky!

NEC 314.16(B) does not include wire-splicing or wire-connecting devices in its calculations; however, your concern is not misplaced, as the AlumiConn is indeed a chunky critter compared to a regular wirenut. Fortunately, I doubt most folks will complain if you whack a surface raceway extension (starter) box onto the existing receptacle box to provide extra space, though. If you have metal boxes, you can also use a standard single gang extension box or mud ring, but nonmetallic box extensions do not appear to be able to be stood off from the underlying wall surface, which is unfortunate when box volume is the reason for the extension.

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