Last winter, the administrative offices had repeated nuisance tripping of circuit breakers. The response from maintenance was to reset the tripped breaker and check the current draw with a clamp-on inductive ammeter. In every instance, things appeared normal after reset. The office manager, anticipating a repeat this year, wants a key to the electrical closet so he can reset the breaker(s) himself. The plant engineer wants you to determine the cause, so a showdown won’t be necessary.
Where do you start?
Since this happens in the winter, it’s likely that individuals are bringing in their own little space heaters and overloading the receptacle circuits. They probably haven’t brought those in yet. So now is the time to take baseline current readings on all breakers.
Next, you need predictive data. If you’re unable to put the affected distribution panel(s) on your power monitoring system, use a portable power analyzer that can log the time an event happens.
If you know the time of the first nuisance trip, you can predict when another will occur on the following day. Slightly before that time, have every available electrician do a “surprise inspection” of the cubicles to look for heaters, daisy-chained surge strips, and other problems. You will find your tripping cause(s).
