NEMA publishes AB 4 for Moulded Case Circuit Breakers
The National Electrical Manufacturers Association (NEMA) has published NEMA AB 4-2009, “Guidelines for Inspection and Preventive Maintenance of Moulded Case Circuit Breakers Used in Commercial and Industrial Applications”, which was last revised in 2003.
The standard presents procedures for identifying moulded case circuit
breakers requiring maintenance or replacement. It contains instructions
for non-destructive tests for verifying specific operating
characteristics, and discusses safety procedures and the operation of
accessory devices. This revision features updates to the test equipment
mentioned to reflect changes in technology and a revised definition of
NEMA AB 4 may downloaded at no charge, or a hardcopy purchased for $75, by CLICKING HERE .
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