.
The National Electrical Safety Code now requires
arc flash analysis in outdoor substations
Arc Flash Assessments for Open Switchyards from Schneider Electric
Field Services
Schneider Electric Field Services provides arc flash assessments on open
switchyards per the National Electrical Safety Code® (NESC®)
requirements. Introduced in the 2007 version of the NESC (IEEE
Standard C2), these requirements apply to electric supply stations
and the overhead and underground electric supply lines.
NESC arc flash calculations will
affect facilities for generation,
transmission and distribution
of electrical power.
The methodology used by NESC is also referenced in NFPA® Standard
70E for use on certain industrial substations (open switchyard
equipment), which may be either customer owned or utility owned.
Benefits of Performing the Arc Flash Assessment
• Compliance with NESC Article 410
• Improved worker safety when combined with a comprehensive safety policy
• Compliance with requirements of underwriting agencies and insurance
companies
• Improvement in reliability as a result of reduced system downtime
The National Electric Safety Code and the NESC are
registered trademarks of the Institute of Electrical and
Electronics Engineers, Inc. NFPA is a registered
trademark of the National Fire Protection Association, Inc.
Additional Services
Our Power System Engineers perform a variety of
power system studies, assessments and improvement
projects to enhance the reliable and safe operation of
the customer’s electrical distribution system.
How are NESC calculations different from IEEE 1584?
IEEE 1584 is the de facto standard for calculating arc flash energies on
industrial equipment up to 15KV. NFPA 70E Standard for Electrical Safety
in the Workplace references several methods for calculating arc flash energies; it references both IEEE 1584 and a methodology similar to NESC
Article 410. There are significant differences in these two:
• NESC uses the line-to-ground fault current for arc flash calculations.
IEEE 1584 uses the three-phase fault current.
• The basis of the calculations in the NESC are the tables in Article 410.
IEEE 1584 provides empirical formulas for calculating the arc
energies.
• NESC methodology only applies to open switchyards and open
conductors on overhead and underground lines. IEEE 1584
methodology can be applied to enclosed equipment as well as open lines.
The arc flash study includes
• An updated AutoCAD one line diagram of the portion of the system
under study
• Equipment short circuit duty evaluation
• Short circuit rating tabulation and recommendations for improvement
• Tabulation of arc flash clothing categories per the National Electrical
Safety Code (NESC) Article 410
Why Choose Schneider Electric Field Services?
• We have performed over 6,000 system studies.
• We have over 100 professional engineers who are collectively
registered in all the states in the U.S.
- Your arc flash study is developed and stamped by a professional
engineer. In many states this is a legal requirement based upon state law.
• We take responsibility for the overall project including data collection,
analysis and recommendations.
For more information call 888-778-2733 or
visit us online at www.schneider-electric.us/go/fieldservices
We offer a broad range of
service solutions to
support any
manufacturers’ electrical
distribution equipment.
Whether the solution is
refurbishment,
replacement,
maintenance or
recommendations to
optimize your existing
system, our nationwide
network of qualified
experts offers a complete
service package.
Schneider Electric – North American Operating Division
9870 Crescent Park Drive
West Chester, OH 45069
Tel: 513-777-4445
Fax: 513-755-5028
1910HO0914
This document has been
printed on recycled paper.
10-09
©2009 Schneider Electric. All rights reserved.
Why Choose
Schneider Electric
Field Services?