We are adding a soundproof wall over an existing wall. We have an electrical outlet that we want to extend. This will be about four inches or more as we are also adding residual channeling then half inch drywall. How do we extend the outlet to be secure and safe?

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    Where in the world are you, and what size is the box the outlet is mounted in? Also, is the outlet mounted in a metal or plastic box? – ThreePhaseEel Nov 24 '16 at 22:05
  • the outlet is a regular size with two plug ins. We live in the Vancouver area. Mounted in a metal box. We got a metal extension but it is not deep enough – Mary Joy Lovering Nov 24 '16 at 22:09
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    How far is it not deep enough by? – ThreePhaseEel Nov 24 '16 at 22:17
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    Not like this: imgur.com/gallery/45Fs1Cd – Grant Nov 24 '16 at 23:00
  • Keep in mind you are not allowed to bury ANY electrical box, even if you have other outlets you don't need. Every electrical box must be accessible without disassembling the building (i.e. no tools). I see many old Victorians with a cabinet door in a wall, it covers up the in-wall tub/shower plumbing. That would also satisfy this requirement. – Harper - Reinstate Monica Nov 25 '16 at 0:45

Extension boxes stack

You can use multiple extension boxes in this situation -- I'd go back to the hardware store and get an extra extension box as well as a couple of mud rings of different depths if I were in your shoes. You may need to move the box to get enough wire length sticking out, though -- you need a minimum of 6" of slack with 3" of that sticking out the face of the box.

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  • Unless the wires are long enough to reach several inches past the outer surface of the new wall extensions will do no good. Are the wires in this box a termination or does power come in on one cable and another go out on another cable? – Jim Stewart Nov 25 '16 at 1:44
  • @JimStewart good point. Perhaps you could attach pigtails to the ends of the wires before putting the extensions on? – ThreePhaseEel Nov 25 '16 at 1:47
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    But then the electrical splice would be so deep that one could not get to it. One possibility is that if the original wall is an interior wall, the box could be turned around to come out the other side of the wall. Then a short length of cable could be joined in the box and sent across the wall to a new box in the sound proof wall. Just put a cover plate on the box. – Jim Stewart Nov 25 '16 at 2:07
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    @JimStewart To free up some more length of wire, you could move the box some 6" higher on the wall. Presto, 6" more wire to work with. – Yehuda_NYC Jan 25 '17 at 14:28
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    The actual code rule for the length of wires coming out of the box is 6in of wire from where it enters the box and it needs to extend minimum 3 in out of the box opening. – Gregory Furmanek Oct 29 '17 at 15:19

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