An electrical connector assembly 1 comprising: a terminal holder 18, and a fastening assembly 20, accommodated within the terminal holder 18, for clamping a plurality of terminals 3, 4 in the direction of a longitudinal axis L for an electrical connection between said terminals 3, 4, said fastening assembly 20 including a first fastening member 23 made of a metal material and a second fastening member 29 which first and second fastening members 23, 29 are connected to each other for clamping said terminals 3, 4 and which define a terminal receiving area 37, wherein the electrical connector further comprises an insulation arrangement 30 which is arranged between said first fastening member 23 and the terminal receiving area 37.