IEEE C37.20.7-2001

This guide establishes a method by which medium-voltage metal-enclosed switchgear, as defined by IEEE Standards C37.20.2 and C37.20.3, may be tested for resistance to the effects of arcing due to an internal fault. This guide applies only to equipment utilizing air as the primary insulating medium and rated above 1000VAC. It applies to both indoor and outdoor equipment, however special consideration must be given to the building size and construction for indoor applications ( not addressed by this document). The tests and assessments described in this guide are only applicable to arcing faults occurring entirely in air within the enclosure when all doors and covers are properly secured. This guide does not apply to arcing faults which occur within a component of the switchgear assembly, such as instrument transformers, sealed interrupting devices, fuses, etc. Switchgear designs which meet the requirements of this guide will be referred to as arc resistant metal-enclosed interrupter switchgear or arc resistant metal-clad switchgear as applicable, or generally, as arc resistant switchgear.