I've been using 3/4" schedule 40 PVC for three 6-gauge THWN wires coming from the main house panel, exiting the house to the outside and into an 18-ft. deep trench, and leading to an EVSE (electric car charger) near a chain link fence about 30-ft. away from the house.
Do you think it's necessary to convert to schedule 80 for the vertical section coming out of the house down to the trench, and up from the ground to the EVSE at the end of the run? (I’m not sure if either location is subject to “physical damage.”) The only thing I can think of is possibly dinging it with my lawnmower.
I'd prefer, of course, to just continue with schedule 40 if I can.
And if I should use schedule 80, would it be wise to transition to 1” instead of 3/4” conduit for those vertical sections for wire pulling reasons?