Valdemar said:
Keep in mind that #6 NM cable is 60C and rated at 55A, considering you need to de-rate the breaker for continuous load 20% you are pretty much limited to a 40A breaker, or maybe 44A if they exist, hardly a future-proofing.
You derate the load, not the breaker. That is, a 32 amp continuous load requires a minimum 40 amp conductor and a minimum 40 amp breaker. The reason for this is that standard breakers may trip below their rating if used continuously, so you need a larger breaker to avoid this. Then because the breaker is larger, you need larger conductors to ensure the conductors are adequately protected by the breaker.
Valdemar said:
Running NM inside a conduit can be a code violation, or at least you need to use a larger than necessary diameter conduit to make it compliant.
Not a code violation in and of itself. For a complete conduit system, you need to take the largest width of the NM cable, treat the cable as a circle, calculate that circle's area, and proceed accordingly. If that's the only wiring in the conduit, I believe the allowed fill is 60% of cross-sectional area. The upshot is that the inner diameter of your conduit would need to be 130% of the width of the cable in that case (1 / sqrt(60%)). [Edit: should be 53% fill and 138%.]
However, no such requirement applies for incomplete runs of conduit used solely to protect the NM cable from physical damage. So if you are only using the conduit in the garage, have at it. The above sizing may still be a good idea, though. Also, where the cable enters the conduit, a bushing with a smooth surface is required to prevent damage to the cable.
Valdemar said:
You could strip the outer sheating of the NM and run individual conductors inside the conduit, this is not by code but some think it is acceptable.
This is code compliant if the individual conductors are marked with their type, e.g. THWN. If unmarked, it is not compliant.
Also, as for the connection to the OpenEVSE, if you use a cord gland, then you are using cord, and you can not hard wire the EVSE. You'll need to use a plug and receptacle. If you want to hard wire the EVSE, then ditch the cord gland and run your protective conduit and NM to that opening. No splicing outside the EVSE required.
The above is all per the NEC; the CEC may differ.
Cheers, Wayne