With AHJ approval an additional service may be the standby source, using separate service conductors from the utility installed electrically and physically remote from the others. Also with AHJ approval, a connection ahead of the service disconnecting means, but never inside the cabinet, enclosure or vertical section that holds it, may be the standby source, kept far enough from the main service disconnect that one event is unlikely to take out both.
This control maps to 1 controls across 1 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 1 it maps to, and the evidence behind each claim, over MCP and REST.