Yep, the rules are different here than in Canada.

All wiring is subject to the approval of the electrical inspection. That said, in most areas, there is little if any attention paid to the low voltage. Mainly they look to see if it's fire caulked and that someone didn't drill through something they shouldn't have. But some areas are much stricter.

But, the original question is, if you remove the outer jacket, are the inner speaker wires rated for in wall use