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I currently have a (completely miswired) TT30R in a metal box and metal conduit on the exterior wall:

enter image description here

The wiring is 2x6AWG for hot and 2x10AWG for neutral on a (currently) 40A breaker. So I have everything I need.

I would like to remove the TT30R and replace with a hardwired EVSE. If possible I would like to reuse the metal box (so that I do not need to patch and re-drill holes in the exterior stucco wall, which is hard). But at the very least I want to reuse the conduit.

Is this standardized in any way (similar to indoor 120V jboxes)? Can I fit EVSE without removing the box?

If not, what is the best (=easiest while staying safe and code compliant) way to replace this with an EVSE?

Note: My question is not about the wiring itself but the mechanical, hardwired install. (Wires are enough with sufficient gauge and they will be wired correctly at the panel as well)

PS: Please do not comment on the current wiring. I have no clue on which drugs the person was, who did this. I am just happy I always had this breaker off and never used this receptacle.

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    I believe most EVSEs do not use neutral, except for 120 volts. If it is wired correctly at the panel, you have two hots(240v) plus ground, plus the neutral. It should be easy to remove the receptacle, wire the hots and ground and capped the neutral and charged away into the sunset.
    – crip659
    Jan 15 at 23:12
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    Yeah... that's terrifying! I'd check other outlets/switches/everything electrical. Just to be sure...
    – FreeMan
    Jan 15 at 23:23
  • @crip659 To clarify, the question is not about the wiring but about the mechanical installation. Wiring itself will be done correctly.
    – divB
    Jan 16 at 0:36
  • At least it's taped. That's most important. :)
    – jay613
    Jan 17 at 12:49

1 Answer 1

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EVSE mounting plates are not standardized, but generally they're a lot larger than that box you've got. Even if you could attach an EVSE to the front of that box, it'd be pretty awkward.

The cleanest solution would be to remove the existing box and attach the conduit to the EVSE, if the EVSE supports attaching EMT.

The other option would be to keep the existing box as a junction box, mount the EVSE nearby, and run a short piece of new conduit from the existing box to the EVSE using one of the unused knockouts (possibly using flexible conduit - Liquid-Tight or LFNC - if you don't want to deal with bending solid metal conduit).

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  • Good answer - with one heads up being LFNC is often rated only for 60C in a wet location, so make sure to wire with conductors sized for that temperature rating.
    – KMJ
    Jan 16 at 3:04
  • Good call on reusing the box. OP might see value in having 120V outlets outside too, perhaps for vacuuming the electric car or other outside power tools.
    – Criggie
    Jan 16 at 21:46
  • Are you aware of any EVSE that supports attaching EMT? I have a hard time finding (I know buying recommendations are off topic but this is independent of the answer, which I already accepted)
    – divB
    Jan 17 at 8:01
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    @divB the Tesla wall connector has 3/4" knockouts at the top, bottom and back that can take EMT perfectly well. Have done it almost a dozen times.
    – peter
    Jan 20 at 20:35

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