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NEMA Publishes AB 4-2009 Guidelines for Inspection and Preventive Maintenance of Molded Case Circuit

NEMA AB 4 presents procedures for identifying molded case circuit breakers requiring maintenance or replacement. It contains instructions for non-destructive tests for verifying specific operating characteristics, and discusses safety procedures and operation of accessory devices. This revision features updates to the test equipment mentioned to reflect changes in technology and a revised definition of “qualified person.”

 “Regular inspection and preventive maintenance are essential for ensuring a high level of protection of personnel and electrical equipment,” said Ed Larsen, a member of the Low Voltage Distribution Equipment section, which produced the standard. “NEMA AB 4-2009 describes the necessary procedures and precautions for maintainers of molded case circuit breakers.”

 NEMA AB 4 may downloaded at no charge, or a hardcopy purchased for $75, by visiting, or by contacting IHS at 800-854-7179 (within the U.S.), 303-397-7956 (international) 

NEMA is the association of electrical and medical imaging equipment manufacturers. Founded in 1926 and headquartered near Washington, D.C., its approximately 450 member companies manufacture products used in the generation, transmission and distribution, control, and end use of electricity. These products are used in utility, industrial, commercial, institutional, and residential applications. The association’s Medical Imaging & Technology Alliance (MITA) Division represents manufacturers of cutting-edge medical diagnostic imaging equipment including MRI, CT, x-ray, and ultrasound products. Worldwide sales of NEMA-scope products exceed $120 billion. In addition to its headquarters in Rosslyn, Virginia, NEMA also has offices in Beijing and Mexico City.

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