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NEMA Publishes NEMA AB 3 Molded Case Circuit Breakers and Their Application

The National Electrical Manufacturers Association (NEMA) has recently published NEMA AB 3, "Molded Case Circuit Breakers and Their Application." This application guide covers molded case circuit breakers and molded case switches, single-pole and multi-pole, fused and unfused, and their accessories. These circuit breakers and switches are assembled as integral units in supporting housings of insulating material and have rated voltages up to and including 1000V, 50/60Hz, ac or ac/dc, and have rated interrupting current ratings of 5000A or more.

Updates to this publication include the addition of photovoltiac circuit breakers, National Electrical Code (NEC) references, and diagrams. NEMA AB 3 may be downloaded at no cost at A hard copy may be purchased for $92 by visiting, or contacting IHS by phone at (800) 854-7179 (U.S. only) or (303) 397-7956 (international).

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