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Application of new technologies in power circuit breakers with higher interrupting capacity and short time ratings

A new low voltage power circuit breaker (LVPCB) has been introduced which has higher interrupting capacity and higher short delay current ratings than previously available in LVPCBs. The entire new power circuit breaker including operating mechanism and contacts has been designed and tested to meet or exceed the stringent requirements of ANSI standard C37.16 "Low-Voltage Power Circuit Breakers and AC Power Circuit Protectors-Preferred ratings, Related Requirements, and Application Recommendations", ANSI C37.50 "Low-Voltage AC Power Circuit Breakers Used in Enclosures-Test Procedures" and ANSI standard C37.17 "Trip Devices for AC Low Voltage PCBs". This paper discusses the evolution of technology in materials and electronics, which has enabled improved performance, as well as provide examples of specific applications in the industry where the new PCB higher interrupting capacity and short time ratings are beneficial to the user. A need to review both short delay time as well as short delay current ratings of equipment is discussed. Zone selective interlocking functions to reduce damage to protected equipment while still maintaining coordination is also reviewed.