In off-grid systems, a 120 VAC inverter commonly provides power to equipment that is designed for connection to 120/240 VAC, split-phase utility power. This is accomplished by using a jumper to connect both busbars in the service equipment to the same single 120 VAC phase from the inverter. However, to reduce wire expense, multiwire branch circuits-in which a single neutral conductor is used with two "hot" conductors on separate phases-are commonly installed in new construction. With split-phase 120/240 VAC, the neutral conductor never carries the sum of the current from the two circuits, since they are out of phase with each other. However, if the two hot conductors are on the same phase-for example, being supplied by a single 120 VAC inverter-then the currents will be additive on the neutral conductor, possibly overloading it. Allowing standard wiring of the house is one reason for the popularity of the new inverters that provide 120/240 split-phase.
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