UL - 891
UL Standard for Safety Switchboards
|Publication Date:||19 July 2019|
Scope and object
This Standard applies to switchboards nominally rated at 1 000 V or less and intended for use in accordance with the Canadian Electrical Code, Part I (CE Code, Part I), the National Electrical Code (NEC), ANSI/NFPA 70, and the Mexican Standard for Electrical Installations (Utility), NOM-001-SEDE.
In this standard the term switchboard is intended to refer to a dead-front switchboard.
These requirements do not cover the following switchboard types: preset and dimmer control (theater), live front, railway control or electrification; or constructions intended only for receiving motor control center units.
These requirements cover switchboards for use on circuits having available short-circuit currents of not more than 200 000 A.
These requirements do not cover switchboards with short-time current ratings.