CFR > Title 14 - Aeronautics and Space > CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION > SUBCHAPTER C—AIRCRAFT (parts 21 to 50) > PART 25—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES > SUBPART H—Electrical Wiring Interconnection Systems (EWIS) (§25.1701 to §25.1733) > 25.1731—Powerplant and APU fire detector system: EWIS.

25.1731—Powerplant and APU fire detector system: EWIS.

(a) EWIS that are part of each fire or overheat detector system in a fire zone must be fire-resistant.
(b) No EWIS component of any fire or overheat detector system for any fire zone may pass through another fire zone, unless:
(1) It is protected against the possibility of false warnings resulting from fires in zones through which it passes; or
(2) Each zone involved is simultaneously protected by the same detector and extinguishing system.
(c) EWIS that are part of each fire or overheat detector system in a fire zone must meet the requirements of § 25.1203.