Interrupting Capacity

Interrupting Capacity (IC) is the maximum fault current that can be interrupted by a circuit breaker without failure of the circuit breaker. In order to select the proper circuit breaker for your application, you should know what the maximum short circuit current is, at rated voltage,that the circuit breaker would be required to interrupt.

Carling Technologies' circuit breaker product lines offer interrupting capacities that range from 500 to 50,000 amps. The interrupting capacity (IC) for a specific circuit breaker is based on the combination of circuit configuration, current coil rating, maximum voltage rating, frequency, number of poles (or phase), if back up series fusing will be present, and the applicable regulatory agency requirements.

Electrical Tables Available

For each Carling Technologies' circuit breaker product series we offer on-line PDF files that provide electrical tables that detail the relationship between all of these elements. Below is an example of such an electrical table. In this case, the table represents the A-Series Handle circuit breaker as a component supplementary protector.

Using this table the following can be calculated:

  • The interrupting capacity for a circuit breaker with 1) Series Trip circuit 2) maximum voltage rating of 80 Volt DC 3) 25 amp current rating 4) UL/CSA agency approval 5) without back up fuse would be 3000 amps

The PDF files that contain the electrical tables, along with other specifications can be found on the specific series' product page within this web site.