Abstract: A fastener for a reverse fed panelboard circuit breaker is taught. Briefly stated, a resilently deformable pivoting member is disposed between side barrier fins in a two pole panelboard breaker. A pin at one end of the fastener is placed through a screw hole which is contained in the panelboard and disposed between the side barriers of the panelboard breaker, with the fastener rotatably urged towards the breaker so as to, when fully rotated causes the breaker retention tab to be urged against the panelboard retention hook and also for the fastener to lay against and come in contact with the edge of the panelboard breaker thereby preventing removal of the breaker without first removing the fastener.