Abstract: The invention provides a safety electrical connector construction in the form of electrical receptacles carried by a weatherproof housing on a front panel. The receptacles are of insulating material, with attached contactor pins having exposed exterior faces adapted for engagement by cooperable spring-loaded pins of a line plug from a liquid transfer facility that receives electrical information for monitoring tank filling operations. The receptacles have collars which interlock with the line plugs whereby the latter must be manually released prior to the vehicle being driven off after termination of the filling. The mounting of the receptacles includes unique simplified detent means which are arranged to yield under excessive forces experienced thereby, and to release the receptacles from their supporting panels in the case of an emergency, such as if the driver of a vehicle would forget to uncouple the line plug and would drive the vehicle off with the line still connected.