I have a great crawl space under the house and was planning on running all my ICF (exterior walls) electrical straight down and under the house into the crawl space. Am I crazy to staple romex under the house and run it up through 3/4 conduit to the wall sockets when necessary. No horizontal romex cramed in foam for horizontal runs. Seeems it gives me access and adaptability yet doesn't require so much conduit? thanks K52

That sounds very similar to what we used to do in log homes. And it worked fine there.
As long as your electrical inspector is OK with the plan, I see no problems with your ideas.

I think you have to limit the length of your conduit to 8 or 12" to be considered a nipple. have to check the code book for the exact length. if you go longer than the nipple length then romex may not be rated for use in conduit. There are exceptions for exposed locations like an unfinished basement for instance.

Other than that, this exactly how I would run the receptacles, especially if your planning to place them within the base.

thanks guys I'll check with my iinspector. k52

I believe you have to put a conector on the end of the conduit and strip the outer jacket from the romex where it goes thru the conduit.

Cheers,
Joey

Nope on both counts. The NEC allows you to run Romex thru conduit up to 5', I think, maybe 8'. I'd have to check but the length limit is reasonably generous. No clamp is required but the romex will have to be fastened within 6" of the end of the conduit. You're not permitted to strip the outer sheath off the romex, nor can you use wired stripped from romex cable as regular conduit wire. The reason is identification. The individual wires in a romex cable do not carry size, type, etc., info on them. It's all on the outer sheath. All wires must have visible identifying info on them, which individual strands made for conduit use have.