ABSTRACT
Low-voltage switchgear is a commonly used name for metal-enclosed or metal-clad low-voltage power circuit breaker switchgear rated for 600 V alternating current (AC) and below. The metal-enclosed switchgear assembly is completely enclosed on all sides and top with sheet metal (except for ventilating openings and inspection windows) and contains stationary primary power circuit switching or interrupting devices, or both, with buses and connections. The metal-clad low-voltage switchgear contains circuit breakers of removable (rack-out) types which are housed in individual grounded metal compartments. The construction features of metal-enclosed and metal-clad switchgear were described previously in Chapter 7. The service conditions for the design and performance of low-voltage switchgear are based upon ambient temperature from −30°C to +40°C, altitude not to exceed 6000 ft, and switchgear installed in nonexplosive atmosphere.
