MtnDon wrote:That does not seem logical.
You're right, hence my disclaimer. I was going by memory, and it's been a number of years since I dug into an NEC manual. There could have been any number of changes to it since then.
MtnDon wrote: You can hook an incoming 200 amp sized set of wires (such as #2/0 AWG copper) to a 15 amp breaker box. It is the breaker size or the designed maximum load of the box that will limit the amps coming into and going out of the box circuits.
Well, actually, you can't. The lugs in the 15 amp box won't physically accept the size of 2/0 wire. I think the best one could do is about 8 gauge.
MtnDon wrote:But if you connect 30 amp sized wire (#10 AWG) to a panel that is rated for 200 amps you cannot draw more than 30 amps without danger of overheating the 30 amp wires.
Again, I doubt you could actually tighten down the lug screws to grip that 10g wire tight enough. But that's why you fuse/breaker upstream for the 30 amp wiring and panel/box. Remember, the NEC ampacity tables are about
minimum sizes of wire to carry a known maximum current in certain conditions. You can legally run larger wiring.....it's just economically foolish to do so.
MtnDon wrote:Make sense? NEC is about safety.
What you're saying does make a certain amount of sense, and does suggest one consult the latest NEC manual for guidance.
MtnDon wrote:And NEC does not directly apply to RV's. There is a different association that sets the RV rules but they will be similar to NEC residential and commercial rules.
I remember a section pertaining to mobile homes. (Granted, a different animal, to a certain degree.) As I recall, there was discussion as to whether it applied to motor homes or campers. Again, I'd have to consult an NEC on that.
Either way, the NEC is part of the NFPA's rules and guidelines, which is a set of governmental agencies that will surely apply their authority as they see fit.
Roger