What number of short circuits or faults are Square D breakers rated to interrupt?
UL489 listed circuit breakers
This is a summary of what breakers do for UL489. Requirements vary, so please refer to the UL489 for complete details.
At Rated Current (handle rating):
|Frame Size Amperes
||Full Load Operations
||No Load Operations
The circuit breaker is operated making and breaking 600% of its continuous current rating, but not less than 150 ampere.
For circuit breakers through 1600 ampere, the number of 600% operations is 50
For larger circuit breakers through 4000 ampere, the number of operations is 25
For circuit breakers rated 240 Vac and higher, two 10 kA short circuit tests per pole and one test with all poles connected in series is performed. For example, a 3-pole circuit breaker receives seven short circuit tests.
High Available Fault Current Tests (twice at interrupting rating):
After qualifying a set of circuit breakers to the standard tests, a manufacturer can have additional circuit breaker samples tested on higher than standard available fault currents.