So, we have a circuit that runs from the panel to junction box A, then to junction box B, and then onwards to a load. Can the fixed Chapter 3 wiring between junction box A and B be replaced by a flexible cord "pigtail" emanating from junction box B and plugged into a single receptacle in junction box A, to provide for the interchange of the equipment providing the power source to the circuit? (Say, to a generator if this configuration was mounted outdoors and made of outdoor-rated parts, or to an inverter powered by some DC source, or even simply to a different circuit for some bizarro reason.)
It seems to me that while this isn't quite the situation in 400.7(A)(11) as this is field fabricated -- 400.7(A)(6) would hold, as we are connecting some load to facilitate interchange -- just not of the load, but the source powering the load. Or does 400.7(A)(6) not apply, rendering this arrangement a 400.8 violation as it'd be substituting for permanent wiring?