Learning Objective: Recognize the difference types of common electrical hardware used on naval aircraft.

An important part of aircraft electrical mainte-nance is determining the correct type of electrical hardware for a given job. These maintenance functions normally require a joint effort on the part of the AM and the AE/AT personnel. You must become familiar with wire and cable, connectors, terminals, and bonding and bonding devices.

For purposes of electrical installations, a wire is described as a stranded conductor covered with an insulating material. The term cable, as used in aircraft electrical installations, includes the following:

. Two or more insulated conductors contained in the same jacket (multiconductor cable)

. Two or more insulated conductors twisted together (twisted pair)

. One or more insulated conductors covered with a metallic braided shield (shielded cable)

. A single insulated conductor with a metallic braided outer conductor (RF cable)

For wire replacement work, the aircraft maintenance instruction manual (MIM) should be consulted first. The manual normally lists the wire used in a given aircraft.

Connectors are devices attached to the ends of cables and sets of wires to make them easier to connect and disconnect. Each connector consists of a plug assembly and a receptacle assembly. The two assemblies are coupled by means of a coupling nut. Each consists of an aluminum shell containing an insulating insert that holds the current-carrying contacts. The plug is usually attached to the cable end, and is the part of the connector on which the coupling nut is mounted. The receptacle is the half of the connector to which the plug is connected. It is usually mounted on a part of the equipment. One type of connector commonly used in aircraft electrical systems is shown in figure 2-53.

Since most aircraft wires are stranded, it is necessary to use terminal lugs to hold the strands together. This allows a means of fastening the wires

Figure 2-53.Connector assembly.

to terminal studs. The terminals used in electrical wiring are either of the soldered or crimped type. Terminals used in repair work must be of the size and type specified in the applicable maintenance instruction manual. The crimped-type terminals are generally recommended for use on naval aircraft. Soldered-type terminals are usually used in emergencies only.

The basic types of solderless terminals are shown in figure 2-54. They are the straight, right angle, flag, and splice types. There are variations of these types.

An aircraft can become highly charged with static electricity while in flight. If the aircraft is improperly bonded, all metal parts do not have the same amount of static charge. A difference of potential exists between the various metal surfaces. If the resistance between insulated metal surfaces is great enough, charges can accumulate. The potential difference could become high enough to cause a spark. This constitutes a fire hazard and also causes radio interference. If lighting strikes an aircraft, a good conducting path for heavy current is necessary to minimize severe arcing and sparks.

When you connect all the metal parts of an aircraft to complete an electrical unit, it is called

Figure 2-54.-Basic types of solderless terminals.

bonding. Bonding connections are made of screws, nuts, washers, clamps, and bonding jumpers. Figure 2-55 shows a typical bonding link installation. Bonding also provides the necessary low-resistance return path for single-wire electrical systems. This low-resistance path provides a means of bringing the entire aircraft to the earths potential when it is grounded.

Whenever you perform an inspection, both bonding connections and safetying devices must be inspected with great care.