Originally Posted by craneservice
If you come up through the floor you will need to change from pvc conduit to rigid conduit and put in a seal off at each end of the conduit as the garage is a hazardous locations. If you penetrate the wall from outside at least 3' up you need not install a seal off. The panel in the garage will nee to be set up as a sub panel with a separate ground bar. Install a ground rod at the garage and also tie to the ground in the main house. Using wire rated for 100 amps and fuseing it at 50 amps is ok and not a code violation. Are you running the wire above the ground or in a trench? If in a trench I would install a 2" PVC conduit and pull THHN or XHHW wire instead of triplex. I would also use copper if you can afford it.
How do you know this is considered a hazardous location. The OP makes no mention of it even possibly being classified. Unless I missed something in the original post.
OP. You have a good opportunity now to save some time and money later. Since the floor is not poured, get as much installed as possible under the new slab NOW.
Run PVC on the ground and stub up for all switches and receptacles. You may have to dig some as the PVC must be covered with 4" of concrete. (I think)?? Secure the PVC where it will stub up. Like inside wall studs ect.... If using rebar, tie it to the rebar with tie wire.
Then after you have decided what size sub panel you will install, you can bury the conduit entering the garage and stub up for the panel. You do not have to run the whole feeder conduit. Just come out under the structure a few feet and mark the spot with a stake ect... Tape up the end real good unless you are going to run it all at one time. In fact, tape up all stub ends to keep concrete from entering. The concrete will then be poured over all the PVC conduit in the garage. Since you do not have any concerns as to how to route the conduit (it will be covered in concrete) you save conduit and wire.
I recommend PVC for the feeder and the garage branch circuits because of your circumstance. Of course you can transition to NM or EMT once inside the structure, but since most all the conduits will be available from the floor, little conduit will be needed. This is actually a good situation, not a problem.