309 

Federal Aviation Administration, DOT 

§ 23.1367 

§ 23.1359

Electrical system fire protec-

tion. 

(a) Each component of the electrical 

system must meet the applicable fire 
protection requirements of §§ 23.863 and 
23.1182. 

(b) Electrical cables, terminals, and 

equipment in designated fire zones that 
are used during emergency procedures 
must be fire-resistant. 

(c) Insulation on electrical wire and 

electrical cable must be self-extin-
guishing when tested at an angle of 60 
degrees in accordance with the applica-
ble portions of appendix F of this part, 
or other approved equivalent methods. 
The average burn length must not ex-
ceed 3 inches (76 mm) and the average 
flame time after removal of the flame 
source must not exceed 30 seconds. 
Drippings from the test specimen must 
not continue to flame for more than an 
average of 3 seconds after falling. 

[Doc. No. 27806, 61 FR 5169, Feb. 9, 1996] 

§ 23.1361

Master switch arrangement. 

(a) There must be a master switch ar-

rangement to allow ready disconnec-
tion of each electric power source from 
power distribution systems, except as 
provided in paragraph (b) of this sec-
tion. The point of disconnection must 
be adjacent to the sources controlled 
by the switch arrangement. If separate 
switches are incorporated into the 
master switch arrangement, a means 
must be provided for the switch ar-
rangement to be operated by one hand 
with a single movement. 

(b) Load circuits may be connected so 

that they remain energized when the 
master switch is open, if the circuits 
are isolated, or physically shielded, to 
prevent their igniting flammable fluids 
or vapors that might be liberated by 
the leakage or rupture of any flam-
mable fluid system; and 

(1) The circuits are required for con-

tinued operation of the engine; or 

(2) The circuits are protected by cir-

cuit protective devices with a rating of 
five amperes or less adjacent to the 
electric power source. 

(3) In addition, two or more circuits 

installed in accordance with the re-
quirements of paragraph (b)(2) of this 
section must not be used to supply a 
load of more than five amperes. 

(c) The master switch or its controls 

must be so installed that the switch is 
easily discernible and accessible to a 
crewmember. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 
FR 258, Jan. 9, 1965, as amended by Amdt. 23– 
20, 42 FR 36969, July 18, 1977; Amdt. 23–43, 58 
FR 18977, Apr. 9, 1993; Amdt. 23–49, 61 FR 5169, 
Feb. 9, 1996] 

§ 23.1365

Electric cables and equip-

ment. 

(a) Each electric connecting cable 

must be of adequate capacity. 

(b) Any equipment that is associated 

with any electrical cable installation 
and that would overheat in the event of 
circuit overload or fault must be flame 
resistant. That equipment and the elec-
trical cables must not emit dangerous 
quantities of toxic fumes. 

(c) Main power cables (including gen-

erator cables) in the fuselage must be 
designed to allow a reasonable degree 
of deformation and stretching without 
failure and must— 

(1) Be separated from flammable fluid 

lines; or 

(2) Be shrouded by means of elec-

trically insulated flexible conduit, or 
equivalent, which is in addition to the 
normal cable insulation. 

(d) Means of identification must be 

provided for electrical cables, termi-
nals, and connectors. 

(e) Electrical cables must be in-

stalled such that the risk of mechan-
ical damage and/or damage cased by 
fluids vapors, or sources of heat, is 
minimized. 

(f) Where a cable cannot be protected 

by a circuit protection device or other 
overload protection, it must not cause 
a fire hazard under fault conditions. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as 
amended by Amdt. 23–14, 38 FR 31824, Nov. 19, 
1973; Amdt. 23–43, 58 FR 18977, Apr. 9, 1993; 
Amdt. 23–49, 61 FR 5169, Feb. 9, 1996] 

§ 23.1367

Switches. 

Each switch must be— 
(a) Able to carry its rated current; 
(b) Constructed with enough distance 

or insulating material between current 
carrying parts and the housing so that 
vibration in flight will not cause short-
ing; 

(c) Accessible to appropriate flight 

crewmembers; and 

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