UL 347

Medium-Voltage AC Contactors, Controllers, and Control Centers

UL 347

1.1 Scope and object

This standard is applicable to ac contactors with rated voltages of 1 501 to 7 200 V, and metal-enclosed contactor-based controllers, control centers, and other control assemblies and associated equipment with rated voltages of 751 to 7 200 V, designed for operation at frequencies of 50 or 60 Hz on three-phase systems. These requirements cover equipment intended for use in ordinary (non-hazardous) locations and installed in accordance with the applicable local installation codes and standards (see Annex a, Item 1). These requirements, as modified by the applicable national standards for fire pump controllers, also cover fire pump controllers (see Annex a, Item 2).This standard also includes requirements for controllers intended for service entrance applications. (See 5.204 and Annex a, Item 3.)This standard does not cover:

a) equipment for use in classified locations as defined in the applicable installation codes or standards;

b) components contained in contactors and contactor-based controllers for which individual component standards exist; and

c) auxiliary low voltage control assemblies (see Annex a, Item 4).