What does the CAT:A or CAT:B indication on a circuit breaker indicate?

Category A. Circuit breakers not specifically designed for discrimination applications.
Utilization category A: Without an intentional short-time delay for selectivity under short-circuit condition and therefore without a short-time withstand current rating. This category of circuit breaker has no deliberate delay in the operation of the “instantaneous” short-circuit magnetic tripping device Usually molded-case type circuit breakers or modular circuit breaker are category A These circuit breakers may provide selectivity under short-circuit conditions by other means. But manufacturer will not provide the Icw value.

• Miniature Circuit Breakers often relate to Cat:A

• Compact MCCB series (Molded Case Circuit Breakers) often relate to Cat:A

Utilization Category B: With an intentional short-time delay (which may be adjustable) provided for selectivity under short-circuit conditions. Such circuit-breakers have a short-time withstand current rating. Category B. Circuit breakers specifically designed for discrimination, which requires a short time-delay (which may be adjustable) and a rated short-time withstand current in compliance with the standard. In exception the Compact NSX100 to 630 circuit breakers are category A, however, by design, they provide discrimination with downstream devices (see the Complementary technical information guide)

• Masterpact  ACB Series (Air Circuit Breakers) relate to Cat: B

Industrial Grade Circuit Breakers have the Category indication available on the product

Our Complementary Technical Information Guide will provide you exact (Validated) information on Selectivity and Cascading with Schneider Electric Circuit Breakers. This validation can only be given for tested combinations, so is not available for combined Schneider together with non-Schneider protection devices.

Complementary Technical Information Guide

Gepubliceerd voor: Schneider Electric Netherlands