If it has quality boat cable in it now, and
(and this is really the rub) it is properly installed with the correct terminations, I would not rush to rip it out. It's not to code, but it is not necessarily unsafe, either.
In the other thread, I was simply suggesting that any new wire you install, particularly high-current applications such as the 30-amp inverter circuit we were discussing, be done to code.
I have a copy of the current NEC (NFPA 70), and can answer any questions you have. If you want to give me a call, that's fine, too -- just keep it between 9am Pacific, 12n Eastern, and 3:30pm Pacific, 6:30pm Eastern.