The alternate source must carry the total load for the designed duration and never under 2 hours. Generators need on-site fuel for at least 2 hours, fuel transfer pumps are fed from the standby system, sources may not depend only on public gas or municipal water (unless the AHJ approves a low risk of both failing together, which also lifts the on-site fuel rule), batteries and UPS for standby lighting last at least 90 minutes without load voltage dropping below 87.5 percent, automotive batteries are banned, automatic charging is provided, and dual fuel systems switch fuel automatically.
This control maps to 2 controls across 2 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.
Every mapping shown was judged rather than inferred from wording similarity, and the ones that failed review are published too. See the coverage reports and what was rejected.
The graph holds this control, the 2 it maps to, and the evidence behind each claim, over MCP and REST.