Electrical connector assembly and cap connector

An electrical connector assembly provided with a plug connector and a cap connector. The plug connector includes an insulative plug housing with an engagement protrusion and a plurality of elastic first contacts. The cap connector includes an insulative cap housing with an engagement recess for receiving the engagement protrusion. Planar second contacts are arranged within the engagement recess. Each of the second contacts has a pair of contact portions that maintains an interval therebetween. One of the pair of contact portions contacts the first contacts and the other of the pair of contact portions contacts the engagement protrusion to support a biasing force caused by the contact of the first and second contacts when the plug connector and the cap connector are engaged.