UL 891: Switchboards, Tristandard

UL 891: Switchboards, Tristandard

The Tristandard of the North America

Last update 27/01/2020

UL 891: Switchboards

UL 891 is a Tristandard. That means it is exactly the same content in the following three norms:

  • CSA Group: CSA C22.2 No. 244-05.
  • Underwriters Laboratories Inc: UL 891.
  • Association of Standardization and Certification: NMX-J-118/2-ANCE-2012.

The subjects are the SWITCHBOARDS, also called in North America "dead-front switchboard". In Europe the equivalent standards are the EN 61439-1 and EN 61439-2. However the approach is different. EN 61439 puts a lot of emphasis on the Design Verification and cabinet testing. UL 891 is mainly about how to design the switchboard.

The Standard applies to switchboards nominally rated at 600 V or less and intended for use in accordance with the Canadian Electrical Code, Part 1 (CE Code, Part 1), the National Electrical Code (NEC), ANSI/NFPA 70, and the Mexican Standard for Electrical Installations (Utility), NOM-001-SEDE.
These requirements cover switchboards for use on circuits having available RMS symmetrical short-circuit currents of not more than 200 000 A.

Table G3.1

It is one of the most important tables to comply with. It details the minimum distance between bus bars, depending upon the Switchboard declared Shortcircuit current, the Ampere and Voltage Rating.
The bus bars can be arranged in a edge to edge (EE) or face to face (FF) layout. That is important because it changes the minimum distance between them.

 

UL 891 Switchboards

Safety in Collaborative Robotics

There is no “Collaborative Robot”. That is one of the first statements you hear from people working in Collaborative Robotics. The reason is because the robot can be designed for a collaborative task, but it is the Application that makes the “Robot Collaborative”. The reference standard for Collaborative Application is  ISO/TS 15066:2016 - ROBOTS AND ROBOTIC DEVICES -- COLLABORATIVE ROBOTS Not only for the unfortunate title, the standard will be included in the new edition of 2 important standards on Robots: ISO 10218-1: Robotics — Safety requirements for robot systems in an industrial envir