CS 25.1353 Electrical equipment and installations

(See AMC 25.1353)

(a)Electrical equipment and controls, must be installed so that operation of any one unit or system of units will not adversely affect the simultaneous operation of any other electrical unit or system essential to the safe operation. Any electrical interference likely to be present in the aeroplane must not result in hazardous effects upon the aeroplane or its systems except under extremely remote conditions. (See AMC 25.1353(a).)

(b)Electrical Wiring Interconnection System components must meet the requirements of 25.1703, 25.1707, 25.1711 and 25.1717.

(c)Storage batteries must be designed and installed as follows:

(1)Safe cell temperatures and pressures must be maintained during any probable charging or discharging condition. No uncontrolled increase in cell temperature may result when the battery is recharged (after previous complete discharge) –

(i)At maximum regulated voltage or power;

(ii)During a flight of maximum duration; and

(iii)Under the most adverse cooling condition likely to occur in service.

(2)Compliance with sub-paragraph (1) of this paragraph must be shown by test unless experience with similar batteries and installations has shown that maintaining safe cell temperatures and pressures presents no problem.

(3)No explosive or toxic gases emitted by any battery in normal operation, or as the result of any probable malfunction in the charging system or battery installation, may accumulate in hazardous quantities within the aeroplane.

(4)No corrosive fluids or gases that may escape from the battery may damage surrounding aeroplane 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 or;

(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 overtemperature 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. (See AMC 25.1353(c)(6)(ii) and (iii).)

(d)Reserved

(e)Electrical bonding must provide an adequate electrical return path under both normal and fault conditions, on aeroplanes having earthed electrical systems (see CS 25.899).

[Amdt 25/5]

[Amdt 25/18]