The NEC, in general, applies only to the "house" wiring, and not to the insides of equipment. After the disconnect, you're on your own.
This is not always as simple as it sounds. Take the example of an assembly line - many machines wired to act as one. One might argue that the NEC stops at the main control panel; yet, one would also be foolish to ignore the NEC for the power feeds to the sundry motors.
One NEC provision, in particular, can be tricky to follow: the ban on conductors passing through motor starters. Complex machines are often so interconnected that it's impossible not to have control wires going everywhere. At some point that collection of equipment has to become a single "appliance."
In short, there's still a role for professional judgment.
