1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA ICSP 10.1-2015Clarification of Requirements for Service-rated Transfer SwitchesA NEMA Industrial Automation Control Products and Systems Section White Paper NEMA ICSP 10.1-2015 Clarification of Requirements for Service-rated
2、 Transfer Switches Published by: National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org 2015 National Electrical Manufacturers Association. All rights, including translation into other languages, reserved under the Universal Copyright Con
3、vention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American copyright conventions. NEMA ICSP 10.1-2015 2015 National Electrical Manufacturers Association Transfer switches with integral service disconnects are required to be “readily access
4、ible,” per the National Electrical Code (NEC) (NFPA 70). If the service disconnect is integrated into a transfer switch, and the switch is outside in an uncontrolled area, many Authorities Having Jurisdiction (AHJs) have questioned the proper use of “readily accessible” and how that manifests in the
5、 design of the cabinet. In the 2014 NEC code cycle, Code Making Panel 13 clarified the definition of “readily accessible,” which applies to service entrancerated transfer switches, as: “Capable of being reached quickly for operation, renewal or inspection without requiring those to which ready acces
6、s is requisite to use tools, to climb over or remove obstacles or resort to portable ladders and so forth. Where a disconnecting means is required to be lockable open elsewhere in the Code, it shall be capable of being locked in the open position. The provision for locking shall remain in place with
7、 or without the lock installed.” And provided the following exception: “Cord and plug connection locking provision shall not be required to remain in place without the lock installed.” The term “tool” is not defined in NFPA 70 (see NFPA 70, Glossary of Terms, http:/www.nfpa.org/got). Some items are
8、generally agreed to be tools: pliers, screwdrivers, hammers, and saws, for example. Items under discussion include keys, access codes, and biometric scanning. All of these are tools because they have dedicated intended operation and limit access. The use of a key is not in question when the locking
9、provision is to lock the device in the open position as is common in lock-out situations. The key becomes a question when electrical equipment is behind locked gates, doors, or covers, where access to the service device is controlled or partially controlled. Requirements for service entrancerated tr
10、ansfer switch enclosures in outdoor applications: a) A listed transfer switch mechanism; b) 3R or more environmentally restrictive cabinet; c) A provision for locking the service disconnect in the open position; d) Access to live parts shall require a tool; e) One or more service disconnect devices.
11、 Access to the operating means of the service device(s) with either manually or electrically assisted actuation shall be accomplished without the use of tools, as defined above. An external padlock with an exposed shackle shall be permitted, to allow bolt cutters for removal. Locked gates, structura
12、l doors, or equipment doors are typical in public buildings. There is concern for the physical safety of the public, and extra precautions are taken to keep untrained personnel away from electrical equipment. It is up to the AHJ to ensure that a service disconnect behind a locked gate, structural door, or equipment door grants ready access to the proper personnel. NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION 1300 NORTH 17TH STREET, SUITE 900 ROSSLYN. VA 22209www.NEMA.orgTO ORDER ADDITIONAL NEMA STANDARDS VISITWWW.GLOBAL.IHS.COM OR CALL 1-800-854-7179/1-303-397-79565612_0514TB
