Lesson 4/Learning Event 1
Connectors are designed specifically for high- or low-voltage applications. The various connector
receptacles that are available for vehicle usage are classified as in-line or cable, box, wall, or
The in-line type has no means of supporting itself, is used on a cable end, and is joined to a mating
element that also is cable connected. These in-line receptacles permit the interconnection of power
distribution systems using two or more cable or harness assemblies to facilitate maintenance.
The difference between box- and wall-mounted receptacles is related to the environmental
protection of the conductor connections. The box-mounted style has exposed conductor
connections, and is intended to be mounted on a box or component that is sealed and thereby
provides the conductor connections with protection from the environment. A wall-mounted
receptacle is intended to be mounted on an exposed or unprotected enclosure; therefore, the
connections to the conductors are sealed.
The bulkhead receptacle is used to penetrate a panel while maintaining a seal between the
compartments established by the panel. The unique feature of the bulkhead receptacle is that it
allows the connection on both sides of the panel to be removed easily. This is a significant
difference from box- or wall-mounted receptacles, which have only one easily removable
There is also a variety of connector plug assemblies used on vehicles, and the primary physical
difference between them is the backshell configuration. This backshell is used to direct the
connecting wire or cable either axially or in angles up to 90 from the axis of the connector, as well
as to provide a water seal and strain relief for the cable or wire.
Electrical connectors must be capable of withstanding the effects of the military environment.
Protection against damage due to temperature extremes, water, oil, and physical abuse is mandatory.