Addressing nuisance tripping of instantaneous trip breakers in high efficiency motor applications

In reviewing the motor starting current phenomena of high-efficiency motors and the National Electrical Code requirements for instantaneous circuit breakers, the author has determined that there are conflicts. Nuisance tripping of the instantaneous circuit breakers has become more prevalent with the introduction of high-efficiency motors. To address this situation, the author proposes changes to the National Electrical Code and the addition of new test requirements for the qualification or listing of the coordinated protective combination starters. With this in place, new guidelines for setting the adjustment of instantaneous circuit breakers in high-efficiency motor applications could be established. The author maintains that the new method would be easier for the user to apply, permit higher trip settings, and provide improved coordination protection.<>