Backshell

A backshell is a connector accessory — removable mechanical hardware — that threads onto the rear accessory threads of a plug or receptacle connector. Its core function is to mechanically protect the individual harness wires entering the back of the connector and to provide strain relief for the wire terminations. Most backshell designs include an integral clamping device that secures the cable or wire harness to the connector, and some incorporate a tang: a tapering metal projection that accommodates cable-tie attachments to grip and hold the wires exiting the connector.

Beyond mechanical protection, many backshells serve environmental and electrical functions — sealing the connector against dirt and moisture and providing EMI/RFI shielding. Conductive (grounded) backshells are used to terminate cable shields, which are bonded 360° around the circumference to establish a low-impedance ground path. During assembly, backshells are torqued to the values specified by the design or connector manufacturer, and they are sized to accommodate the bends and offsets of the wire harness behind the connector.