Aviation Mechanic - General, Airframe, and Powerplant › II. Airframe › Task K. Aircraft Electrical Systems

AM.II.K.R6

Risk management

Selecting the size of wire in an electrical circuit.

Study note

Get a short, cited explanation of this element written from the FAA handbooks: the core idea, the numbers that matter, common test traps, and a quick self-check.

From the FAA library

Aviation Maintenance Technician Handbook - Airframe p. 9-74
Chapter 9: Aircraft Electrical System › Wire Size Selection › Allowable Voltage Drop
considered satisfactory. When checking a circuit, the input voltage should be maintained at a constant value. Figures 9-122 and 9-123 show formulas that may be used to determine electrical resistance in wires and some typical examples. Figure ... found in Figures 9-122 and 9-123 for the wire size. Calculated voltage drop (VD) = resistance/ft × length × current Electric Wire Chart Instructions To select the correct size of electrical wire, two major requirements must be met: 1. The wire…
Aviation Maintenance Technician Handbook - Powerplant p. 4-51
Chapter 4: Engine Ignition & Electrical Systems › Powerplant Electrical Systems › Voltage Drop in Aircraft Wire & Cable
Figure 4-83. Current-carrying capacity and resistance of copper wire. Figure…
Aviation Maintenance Technician Handbook - Airframe p. 9-98
Chapter 9: Aircraft Electrical System › Electrical System Components › Current Limiting Devices
power source bus. Normally, the manufacturer of the electrical equipment specifies the fuse or circuit breaker to be used when installing equipment. The circuit breaker or fuse should open the circuit before the conductor emits smoke. To accomplish this ... fall below that of the associated conductor. Circuit protector characteristics should be matched to obtain the maximum utilization of the connected equipment. Figure 9-171 shows a chart used in selecting the circuit breaker and fuse protection for copper conductors…