An electrical connector assembly includes a terminal block having a plurality of spaced contact pins mounted thereon and oriented in a first direction. A plurality of openings are formed in the terminal block and each is aligned with one of the contact pins. A plurality of sockets are each mounted at the end of a lead wire and are constructed and arranged to be received in any one of the openings for electrically engaging the contact pin aligned therewith. A locking bar has a plurality of locking portions and is pivotally mounted on the terminal block for movement between an unlocking position and a locking position wherein the locking portions are respectively aligned with one of the openings. A biasing spring engages the locking bar for biasing the locking bar toward its locking position. An end portion of the socket is constructed to engage the locking bar upon being inserted into one of the openings and to move the bar against the biasing spring and away from its locked position until the socket is fully engaged with the contact pin. Each of the sockets has a groove positioned to be engaged by the respective locking portion on the locking bar when the socket is in electrical engagement with said contact pin and a cylindrical portion is formed on the socket for frictionally engaging the margins of the openings as the socket is being inserted or removed from the terminal block for frictionally resisting movement of the socket through the opening.
