I have an outlet box in garage that contains two No. 6 wires that was used for an electric heater. Would like to covert it to a NEMA 14-50 outlet to be used to charge an electric vehicle.

The No. 6 wires come into the box through a 3/4" metal conduit. Do I need another No. 6 for common? And can another No. 6 be pulled through the conduit with the other two 6s already there? The distance of the pull would be about 45 feet with two 90 degree bends.

Thank you very much.

  • What make and model is your car charger? Does it actually use the neutral for anything at all? (My understanding is that most don't.) – ThreePhaseEel Aug 15 '19 at 2:25
  • Alternately can you get a different car charger that doesn't need neutral? That is a pretty stupid requirement... Of course if the circuit is run all the way to the panel in conduit it is certainly easy enough to retrofit neutral... – Harper - Reinstate Monica Aug 15 '19 at 2:43
  • I can attest that there are car chargers that use 14-50 outlets but don’t use the neutral. – DoxyLover Aug 15 '19 at 6:34

You need to determine first as asked in the comments, do you NEED a neutral? That would depend on the car requirements. Refer to the car manufacturer's manual. The power supply is just dumb power. All the fancy charging logic circuitry is in the car.

NEC chapter 625 has specs for the charging system. Note it has to be GFCI, possibly AFCI too, depending on where it's installed. Free code lookup here- https://www.nfpa.org/NEC/About-the-NEC/Explore-the-2017-NEC?openpage=106&access=open (free registration required) unfortunately without search function- Chapter 9, tables 4 and 5 have your answers about conduit fill.

Chatty explanation here- http://www.codebookcity.com/codearticles/nec/conduitfill.htm

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