Sizing Conductors

[ESolar]

EV charging
~45 ft run in existing 3/4" EMT
Will get hot because it's routed between the ceiling and roof (I assume 123 - 131 F).
What is the largest conductor and continuous load?
Here is my answer.

6 Gauge 90 degree C THHN (three conductors and a smaller #10 ground)
75 degree C termination

310.15(B): 65 amp conductor (based on the 75 degree C termination)
310.15(B)(2)(a): I derate the conductor for temp by 0.76

65 amps x 0.76 = 49.4 amps; Not quite 50 amps, but very close.
So I assume that am relegated to a max 45 amp OCPD (versus 50 amp) breaker and a max continuous load of 36 amps.

But then I find that this online calulator gives a different answer: http://www.electrician2.com/calculators/wireocpd_ver_1_reverse.html

Here they rate the conductor at 57 amps (75 amps for the 90 C wire) x 0.76 = 57 amps and a recommended 60 amp OCPD for a continuous load of 48 amps.
They also recommend a #10 ground.

What's the right answer? Can I put in a 50 or 60 amp OCPD, or am I limited to the 45 amp?

 

[Little Bill]

Duplicate to this.............

Electric Vehicle Wiring

The Tesla wall charger is single phase 200 - 240 AC. It operates with up to a 60 amp OCPD for 48 anp continuous. For conductors they spec the following: "If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors. NOTE: Upsize conductors if...

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