A Masterpact NW or Powerpact P or R frame circuit breaker has gotten wet and is nuisance tripping; what should be done?
Masterpact and Powerpact circuit breakers
Circuit breakers may become wet for a variety of reasons including spray, rain, snow, condensation in outdoor enclosure, and begin nuisance tripping
Masterpact and Powerpact P and R breakers which have gotten wet are prone to nuisance tripping. Water will interfere with normal operation of the current sensors, reporting more current to the trip unit than actually exists, resulting in tripping with Ir, Ii, Ig, Ap indication, or no indication. Which function trips depends on the magnitude of phantom current reported to the trip unit.
It is also possible for water to compromise the trip unit causing nuisance tripping.
Once a circuit breaker has become wet enough to nuisance trip, it cannot be restored to reliable operation and the recommendation of NEMA and of Schneider Electric is to replace the breaker.