UL 347:2020 PDF Download

UL 347:2020 standard specifies requirements for AC contactors, controllers, and control centers that are used in medium-voltage applications. The standard covers equipment operating at voltages ranging from 1,501V to 15kV, with a frequency of either 50 or 60 Hz in three-phase systems.

The scope of the standard includes contactors, controllers, control assemblies, and associated equipment designed for use in ordinary (non-hazardous) locations and compliant with local installation codes and standards. Additionally, it includes provisions for fire pump controllers, as well as controllers intended for service entrance applications. The standard also covers equipment with solid-state switching elements used for various purposes, such as starting, stopping, regulating, controlling, or protecting heating and resistive loads.

However, the standard does not cover equipment intended for use in classified (hazardous) locations, components that have their own individual standards, or auxiliary low voltage control assemblies. It also does not include electronic or solid-state devices, circuits, or systems, and excludes electronic variable speed motor controllers. Moreover, controllers that solely utilize solid-state devices in the main circuit are not addressed by this standard.