Test procedures for enclosed low-voltage ac power circuit breakers

NEMA publishes ANSI/NEMA C37.50 Low-Voltage AC Power Circuit Breakers Used in Enclosures—Test Procedures

Rosslyn, Va.—The National Electrical Manufacturers Association (NEMA) has published "ANSI/NEMA C37.50 Low-Voltage AC Power Circuit Breakers Used in Enclosures—Test Procedures."

The first new edition in 24 years, ANSI/NEMA C37.50 covers the test procedures for enclosed low-voltage ac power circuit breakers as follows:

a) Stationary or drawout circuit breakers of two-, three-, or four-pole construction, with one or more rated maximum voltages of 635 V (600 for units incorporating fuses), 508 V, and 254 V for application on systems having nominal voltages of 600, 480, and 240 V.

b) Unfused or fused type circuit breakers.

c) Manually operated or power operated circuit breakers with or without electromechanical or solid-state trip devices.

d) Fused drawouts consisting of current-limiting fuses in a drawout assembly intended to be connected in series with a low-voltage ac power circuit breaker to form a non-integrally fused circuit breaker.

This document applies to both integrally and non-integrally fused circuit breakers.

For more information about NEMA or other ac power circuit breakers, click here to go to Utility Products' Buyes Guide.

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