Historical
NEMA ANSI C37.51:2003
For switchgear - metal-enclosed low-voltage ac power circuit breaker switchgear assemblies - conformance test procedures
Applies to all metal-enclosed low-voltage ac power circuit-breaker switchgear assemblies designed, tested and manufactured in accordance with ANSI/IEEE C37.20.1-2002.
NEMA: National Electrical Manufacturers Association [nema]