a pre - insertion resistor mechanism for a circuit interrupting device of the type which has a pair of normally - engaged contacts . one of the contacts is movable relative to the other contact in an arc - extinguishing environment to selectively separate the contacts to open a gap therebetween to effect circuit interruption . the contacts are continuously , electrically connected to respective , opposed circuit - connectable terminals on the device . the pre - insertion resistor mechanism includes a pre - insertion resistor electrically connected at one end to one of the terminals . the other end of the resistor carries a stationary electrode . a movable electrode assembly which is electrically connected to the other terminal is mechanically coupled to the movable contact so that upon movement thereof to open the gap , the movable electrode simultaneously separates from the stationary electrode . after a predetermined amount of the movement of the electrode has taken place , a latch assembly uncouples the movable electrode assembly from the movable contact permitting the movable electrode assembly to move back toward the stationary electrode . in this way , when the contacts are subsequently re - engaged , the movable electrode assembly leads the main movable contact so that the movable electrode assembly re - engages the stationary electrode prior to the engagement of the contacts . thus , the circuit is first made between the electrodes , whereat some arcing occurs , with the resistor in parallel with the gap between the main electrodes . when the contacts re - engage , they again carry most of the current through the interrupting device .