an electrical interconnection system having a base unit with a cavity therein containing electrical terminals , an electrical connector adapted to be received within the cavity for mating with the terminals , a shorting clip having contact arms for shorting together at least two of the terminals within the cavity , the contact arms being displaceable therefrom in response to the insertion of the connector , and a retention system for positive retention of the connector to the base disposed along the side of the cavity ; characterized in that the shorting clip is disposed at the bottom of the cavity and the contact arms are collapsible out of engagement with the terminals in response to the insertion of the connector . the interconnection system advantageously having minimal effect on the structure of the base and plug connector where the collapsible aspect of the shorting clip enables incorporation of the retention system along the side of the cavity .