Federal Aviation Administration, DOT

Section 25.1360

(4) No corrosive fluids or gases that
may escape from the battery may damage surrounding airplane structures or
adjacent essential equipment.
(5) Each nickel cadmium battery installation must have provisions to prevent any hazardous effect on structure
or essential systems that may be
caused by the maximum amount of
heat the battery can generate during a
short circuit of the battery or of individual cells.
(6) Nickel cadmium battery installations must have - 
(i) A system to control the charging
rate of the battery automatically so as
to prevent battery overheating;
(ii) A battery temperature sensing
and over-temperature warning system
with a means for disconnecting the
battery from its charging source in the
event of an over-temperature condition; or
(iii) A battery failure sensing and
warning system with a means for disconnecting the battery from its charging source in the event of battery failure.
(c) Electrical bonding must provide
an adequate electrical return path
under both normal and fault conditions, on airplanes having grounded
electrical systems.
[Amdt. 25-123, 72 FR 63405, Nov. 8, 2007]

Section 25.1355

Distribution system.

(a) The distribution system includes
the distribution busses, their associated feeders, and each control and protective device.
(b) [Reserved]
(c) If two independent sources of electrical power for particular equipment
or systems are required by this chapter, in the event of the failure of one
power source for such equipment or
system, another power source (including its separate feeder) must be automatically provided or be manually selectable to maintain equipment or system operation.

spaschal on DSK3GDR082PROD with CFR

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-23, 35 FR 5679, Apr. 8,
1970; Amdt. 25-38, 41 FR 55468, Dec. 20, 1976]

Section 25.1357 Circuit protective devices.
(a) Automatic protective devices
must be used to minimize distress to

the electrical system and hazard to the
airplane in the event of wiring faults or
serious malfunction of the system or
connected equipment.
(b) The protective and control devices in the generating system must be
designed to de-energize and disconnect
faulty power sources and power transmission equipment from their associated busses with sufficient rapidity to
provide protection from hazardous
over-voltage and other malfunctioning.
(c) Each resettable circuit protective
device must be designed so that, when
an overload or circuit fault exists, it
will open the circuit irrespective of the
position of the operating control.
(d) If the ability to reset a circuit
breaker or replace a fuse is essential to
safety in flight, that circuit breaker or
fuse must be located and identified so
that it can be readily reset or replaced
in flight. Where fuses are used, there
must be spare fuses for use in flight
equal to at least 50% of the number of
fuses of each rating required for complete circuit protection.
(e) Each circuit for essential loads
must have individual circuit protection. However, individual protection
for each circuit in an essential load
system (such as each position light circuit in a system) is not required.
(f) For airplane systems for which
the ability to remove or reset power
during normal operations is necessary,
the system must be designed so that
circuit breakers are not the primary
means to remove or reset system power
unless specifically designed for use as a
switch.
(g) Automatic reset circuit breakers
may be used as integral protectors for
electrical equipment (such as thermal
cut-outs) if there is circuit protection
to protect the cable to the equipment.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-123, 72 FR 63405, Nov. 8,
2007]

Section 25.1360

Precautions against injury.

(a) Shock. The electrical system
must be designed to minimize risk of
electric shock to crew, passengers, and
servicing personnel and to maintenance personnel using normal precautions.

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