1、 1 Copyright 2013 IEEE. All rights reserved. Interpretation Section 18. Switchgear and metal-enclosed bus Rule 181A4 Metal-enclosed busGeneral requirements for all types of bus (2012 Edition, pp. 70-71) (3 October 2013) IR574 Question: Rule 181A4 states, “Busways should be marked with the voltage an
2、d current rating for which they are designed, in such manner as to be visible after installation.” If a metal-clad switchgear line-up is installed, and the line-up has a nameplate listing the ratings of the switchgear on one of the equipment panel or doors, does this meet the standard? Or, does each
3、 compartment containing the bus need to be labelled? Interpretation The NESC has different requirements for metal-enclosed switchgear and for metal-enclosed busways. Rule 180B applies to metal-enclosed switchgear. Rule 181 applies to metal-enclosed bus running between pieces of equipment; it does no
4、t apply to the internal bus of a metal-enclosed switchgear line-up. Consequently, Rule 181A4 regarding signage does not apply to a metal-enclosed switchgear line-up. See Rule 180B11 that requires a safety sign in each cubicle of a metal-enclosed switchgear line-up containing more than one high-volta
5、ge source. _ National Electrical Safety Code and NESC are both registered trademarks and service marks of the Institute of Electrical and Electronics Engineers, Inc. The NESC is available from the Institute of Electrical and Electronics Engineers, Inc., 445 Hoes Lane, Piscataway, NJ 08854, USA (http:/standards.ieee.org/)
