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My breaker box is installed flush with the drywall, however I need to run some 6/3 romex out of it to a charging box for a Tesla.

My thought was to come out the bottom of the breaker box, then a few inches down, come out of the drywall and run the wiring from there to my charging box.

Is there any sort of box to make the wiring coming out of the drywall not look like...a wire coming out of the drywall?

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  • Does it have to be romex? IMO, metal conduit would look much cleaner in this application (and may even be code required, depending on where in the world you are).
    – Nate S.
    Dec 16, 2020 at 23:33
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    Conduit is a much better solution to this (and you need "protection from physical damage" if you are out of the drywall, so conduit solves two problems.) Use THHN wires in conduit, NOT 6/3 Cable in conduit. Metal conduit (EMT for the least costly) will also serve as a code approved grounding conductor (no grounding wire needed.)
    – Ecnerwal
    Dec 16, 2020 at 23:40
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    Conduit would run through the drywall all the way to the panel - or you'd surface mount a box and have conduit from the back of it to the panel and from the side of it along the face of the wall. 3/4" EMT will fit your 3 6AWG THHN wires. You can't run wires in the wall without conduit (you can run cable in the wall without conduit.)
    – Ecnerwal
    Dec 16, 2020 at 23:45
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    I'm 95% sure the wire in that situation must be protected in conduit as it would be subject to damage otherwise. Dec 17, 2020 at 1:59
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    @Harper-ReinstateMonica -- nope, there's no hard %fill limit on surface raceways, only manufacturer data tables (386.22), and you can't extrapolate fill from those to conductors not tabled by the manufacturer (386.21) -- I suspect this is due to the irregular cross-sections of many (especially smaller) surface raceway products Dec 17, 2020 at 23:55

1 Answer 1

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As was mentioned in comments, you can't use Romex or other-brand NM cable stapled to the wall surface. Since conduit is required for protection you can save yourself some trouble (wrestling and conduit up-sizing) by using THHN or similar conductors instead.

An "old work box" can be installed in a finished wall. Cut a hole just the right size in the drywall and slide the box in. The old work box provides the path from in the wall to the face of the wall. Old work boxes are available in plastic, but because conduit and THHN are recommended here anyway, I'm showing a metal old work box. You can connect this up to the circuit breaker panel with a pre-threaded rigid conduit nipple or with a segment of conduit and appropriate connectors.

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So, with the old work box providing the pathway to the wall face, next you need to transition into conduit on the wall surface. An easy way to do that is to stack an extension box on the front of the old work box. Conduit exits one of the side walls of the extension box and a blank face plate goes on front.

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  • For ease of pulling cable through the conduit, be sure to use a "sweep" elbow to make the corner from going down the wall to going across the wall. Cheaper (probably) and an easier pull (if only 1 elbow) than using an LB pull box.
    – FreeMan
    Dec 17, 2020 at 16:49
  • Will an 'old work' box accommodate (3) 6 AWG wires?
    – ojait
    Dec 18, 2020 at 0:23
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    @ojait #6 wire requires 5 cu in. The two hot conductors passing through (not spliced and loops less than 12 inches) plus one grounding conductor make 3 units requiring 15 cu in total. Check the size of the actual box selected, but it should fit fine even in a single-gang old work box. The extension added to the front counts toward available box volume too. Even more room can be provided by using a two-gang box.
    – Greg Hill
    Dec 18, 2020 at 0:45
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    @GregHill -- if they're transitioning from NM to Conduit, they'll need to splice, but that puts them at 18.5in3 total since 6/2 NM has a 10AWG ground and they can use 8AWG THHN in the conduit. Note also that putting a KO faceplate on the old work box won't work for a transition to rigid conduit as that violates 314.29 due to the fact you can't get it apart later without destroying the lot :P Dec 18, 2020 at 1:31

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