Code Q&A: Sizing an Optional Standby Generator

NEC rules for sizing an optional standby generator

Q. How do I size an optional standby generator when a manual or automatic transfer switch is installed? (Answer based on 2011 NEC.)

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A. The calculated load on the standby source must be in accordance with Art. 220 or by a method approved by the Authority Having Jurisdiction (AHJ) [702.4(B)].

When using manual transfer equipment, the optional standby power source must have adequate capacity

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