There are panels available that are meant to have wire access on the inside of the structure with the breakers on the outside.
Alternatively you could nipple into a J Box in the crawl space, install barrier strips in the J box, and run your cable from there. Using the barrier strips makes it a neater job and avoids the rat's nest effect of using wire nuts. -- Tom Horne
Tom Horne
"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison