Emergency lighting branch circuits are supplied from a 700.12 source and are either independent of normal lighting with automatic transfer, or two or more circuits from separate complete systems with independent sources, one on the emergency system, kept lit or switched on automatically if either fails. Branch circuits for equipment classed as emergency transfer to the emergency source automatically on failure of normal power.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.