I need to install a 14-50 outlet in my garage to charge my car. I have a 200 amp breaker panel on the back of the house. It is approximately a 40' run on the outside of the house to where it would turn into the garage and then another 20' inside the garage to the outlet location. I would prefer to have both the outlet and all of the wire surface mounted and in conduit as it would be very difficult to run inside the wall of the garage.

Do I need to use 2 different wire types for the outdoor and indoor sections? What type of 6/3 wire would I need and what size conduit?


Put it in conduit, use THWN, done. Most THHN is also marked THWN or THWN-2 (and MTW, and perhaps a few other listings.)

Because part of the conduit is outside, the wire used must be wet rated (W) but there's no need to change wire type where it goes inside the building.

Using 6/3 cable in conduit is a right royal pain in the behind you don't need or want. Use individual wires when using conduit - they pull easier and they typically allow you to use smaller conduit per the way the fill rules treat cables .vs. wires.

If you use continuous metallic conduit, that is your ground, you don't need a grounding wire, and you can use 3/4" conduit (minimum.) If you use PVC conduit you need a grounding wire and you'll need 1 inch schedule 80 minimum (which most "home centers" will not stock, but any electrical supply will have tons of) because it sounds like most of the run is going to be below 8 feet and thus considered "subject to damage" so it needs the additional protection of the heavier wall of schedule 80. Don't use Sch 40 becasue it's all you can find at the home center. Go find the electrical supply. The wire may cost less there too...

  • ok but I don't need to "pull" the cable through an existing mounted conduit. I was planning on sliding the loose pieces of conduit onto the cable and then piecing it together and mounting on the wall with the cable already in it. My local home depot does carry schedule 80 which the guy working there did mention I would need for exterior but do I need that for the interior run also since its below 8'?
    – Chris L
    Aug 21 '20 at 14:50
  • So buy the wire like this?
    – Chris L
    Aug 21 '20 at 15:05
  • 4
    @ChrisL yes you do need to pull the wires. You can't assemble the conduit around the wires. I know that sounds clever, but it is specifically prohibited. Aug 21 '20 at 15:09
  • can the ground (bare copper wire) be less than 6 awg?
    – Chris L
    Aug 21 '20 at 15:23
  • 3
    @chrisl yes, for #6 THWN use a #8 ground. For #8 THWN use a #10 ground. Aug 22 '20 at 2:09

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