jar546
Forum Coordinator
Here is some more information on MWBCs.
210.4 Multiwire Branch Circuits.
(A) General.
Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire circuit shall be permitted to be considered as multiple circuits. Except as permitted in 300.3(B)(4), all conductors of a multiwire branch circuit shall originate from the equipment containing the branch-circuit overcurrent protective device or protective devices.
Informational Note No. 1:
A 3-phase, 4-wire, wye-connected power system used to supply power to nonlinear loads might necessitate that the power system design allow for the possibility of high harmonic currents on the neutral conductor.
Informational Note No. 2:
See 300.13(B) for continuity of grounded conductors on multiwire circuits.
So, essentially, using a multiwire branch circuit as multiple circuits satisfies the requirement for providing two small appliance branch circuits for countertop receptacle outlets in a dwelling unit kitchen. Power supplies for equipment such as computers, printers, electric-discharge lighting systems, and adjustable-speed motor drives can introduce harmonic currents in the system neutral conductor. The resulting total harmonic distortion current could exceed the load current of the device itself.
See also 310.15(E) and its enhanced content for information on neutral conductor ampacity.
210.4 Multiwire Branch Circuits.
(A) General.
Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire circuit shall be permitted to be considered as multiple circuits. Except as permitted in 300.3(B)(4), all conductors of a multiwire branch circuit shall originate from the equipment containing the branch-circuit overcurrent protective device or protective devices.
Informational Note No. 1:
A 3-phase, 4-wire, wye-connected power system used to supply power to nonlinear loads might necessitate that the power system design allow for the possibility of high harmonic currents on the neutral conductor.
Informational Note No. 2:
See 300.13(B) for continuity of grounded conductors on multiwire circuits.
So, essentially, using a multiwire branch circuit as multiple circuits satisfies the requirement for providing two small appliance branch circuits for countertop receptacle outlets in a dwelling unit kitchen. Power supplies for equipment such as computers, printers, electric-discharge lighting systems, and adjustable-speed motor drives can introduce harmonic currents in the system neutral conductor. The resulting total harmonic distortion current could exceed the load current of the device itself.
See also 310.15(E) and its enhanced content for information on neutral conductor ampacity.
