An electrical connector for connecting the bare end of an insulated conductor with an electrical contact, including a connector housing containing a chamber in which are mounted a bus bar connected with the contact, and a clamping spring normally biased toward the bus bar. A retaining device maintains the spring in a retained open condition spaced from said bus bar, thereby to permit the conductor bare end to be introduced into the chamber toward a clamping position adjacent the bus bar. An operating member is displaced in a controlled manner to release the spring from its retained condition, whereby the spring biases the conductor toward electrical engagement with the bus bar. To remove the conductor, the operating member is operated again to displace the spring toward its open condition.