an electrical receptacle includes a receptacle housing , a movable element , an interlock mechanism , a release mechanism , and a blocking element . the receptacle housing has a receptacle opening having a longitudinal axis . the movable element is located within the receptacle opening and is designed to move along the longitudinal axis between an extended position and an inserted position . the interlock mechanism is connected to interlock with the movable element when the movable element is in the inserted position . the interlock mechanism also maintains the movable element in the inserted position . the release mechanism is coupled to the interlock mechanism , accessible from outside the receptacle housing , and operable to disengage the interlock mechanism from the movable element to permit the movable element to move to the extended position . the blocking element is located within the receptacle opening and is designed to move along the longitudinal axis with the movable element , to fixedly block a portion of the receptacle opening when the movable element is in the inserted position , and not to fixedly block the receptacle opening when the movable element is in the extended position .