A tamper resistant pin connection for use in a plasma arc cutting apparatus is provided that comprises a plurality of locking fingers within a hollow internal channel of a housing that secure a negative lead gas carrying pin within the housing. The pin comprises a first collar with a shoulder disposed thereon, and accordingly, the locking fingers engage the shoulder to secure the pin within the housing. The pin further comprises a second collar that blocks access to the locking fingers through a first portion of the hollow internal channel such that the locking fingers cannot be accessed to disengage the pin. Further, the pin is recessed within a second portion of the hollow internal channel to prevent further access to the pin for a tamper resistant pin connection.