(a) The electrical power system must have a power source and a separate emergency power source, so that failure of one source does not affect the capability of the other source. The system must meet NFPA 70 (incorporated by reference, see § 127.003).

(b) The emergency power source must provide enough power for the operation of the—

(1) Emergency shutdown system;

(2) Communications equipment;

(3) Firefighting equipment; and

(4) Emergency lighting.

(c) If an auxiliary generator is used as an emergency power source, it must meet Section 700.12 of NFPA 70 (incorporated by reference, see § 127.003).