MASTER YOUR CASTLE with your new build or reno project
Enter competition

How many faults can a breaker interrupt?



What number of short circuits or faults are Square D breakers rated to interrupt?

Product line:  
Circuit breakers

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
0-100 6,000 4,000
101-225 4,000 4,000
226-600 1,000 5,000
601-800 500 3,000
801-2500 500 2,000
2501-4000 400 1,000

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.

Short Circuit: 
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.