Last edit: 03/03/2023
Branch circuit:it is the utility circuit; it is the part of the circuit that starts from the load (e.g. motor) and ends at the first short circuit protection (Branch Circuit Protection Device or BCPD).
Feeder circuit: indicates the supply circuit, i.e. all the elements upstream of the BCPD.
Power circuit: the power circuit (e.g. motor starter); it can be connected directly to the supply circuit or supplied by a power transformer.
Control circuit: it is the circuit that transmits the control signals for the machines or the system. Control circuits are generally limited to 15 A.
Power circuits and Control circuits require the appropriate protection devices (UL 508, UL 489 or UL 1077).
An example of Branch Circuit and Feeder Circuit taken from the Standard is shown in the figure here next.