IEEE 1584.1 - 2013 Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard

IEEE Industry Applications Society

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IEEE 3 Park Avenue New York, NY 10016-5997 USA

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IEEE Std 1584.1™-2013

IEEE Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard Calculation Study in Accordance with IEEE Std 1584™ Sponsor

Petroleum and Chemical Industry Committee of the

IEEE Industry Applications Society Approved 11 December 2013

IEEE-SA Standards Board

Authorized licensed use limited to: Memorial University. Downloaded on August 01,2014 at 06:55:33 UTC from IEEE Xplore. Restrictions apply.

Abstract: Guidance for the specification and performance of an arc-flash hazard calculation study, in accordance with the process defined in IEEE Std 1584™, is provided in this document. It outlines the minimum recommended requirements to enable the owner or its representative to specify an arc-flash hazard study, including scope of work and associated deliverables. Keywords: arc fault currents, arc-flash boundary, arc-flash hazard, arc-flash hazard analysis, arc-flash hazard marking, arc in enclosures, arc in open air, bolted fault currents, electrical hazard, IEEE 1584.1™, incident energy, protective device coordination study, short-circuit study, working distances

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The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright © 2014 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 10 February 2014. Printed in the United States of America. IEEE is a registered trademark in the U.S. Patent & Trademark Office, owned by The Institute of Electrical and Electronics Engineers, Incorporated. PDF: Print:

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Participants At the time this IEEE guide was completed, the Arc-Flash Hazard Calculations Working Group had the following membership: Daleep C. Mohla, Chair L. Bruce McClung, Vice Chair Jim Phillips, Secretary/1584.1 Team Vice Leader Kenneth S. Jones, 1584.1 Team Leader

Daniel Adjetey Jean Ayoub James Babcock Ilanchezhian Balasubramanian Pirooz Barkhordar Louis Barrios Terry Becker James Beyreis Joshua Billman Waylon Bowers Rachel Bugaris Eric Campbell Ray Catlett Eva Clark Craig Clarke D. Ray Crow Steve Dittman Maurice D’Mello Daniel Doan Paul Dobrowsky Mike Doherty Gary Donner Ryan Downey Paul Eaton Rakan El-Mahayni Steve Emert

Tim Faber Mark Fisher Frank Foote Robert Fuhr Tammy Gammon Tim Gauthier John Hempstead Dennis Hill Robert Hughes Ben C. Johnson Dee Jones Mike Lang Robert G. Lau Wei-Jen Lee Kevin J. Lippert Albert Marroquin Larry McGuire John McQuilkin Peter Megna James Mitchem Roger Morgan Dean Naylor Dennis Neitzel John Nelson Mike Noonan Wheeler O’Harrow Sergio A. Panetta

Tom Papallo Anthony Parsons Brian Radibratovic Bob Ragsdale Ken Rempe Dave Rewitzer Tim Rohrer Rupeto Sanchez Vincent Saporita Todd Sauve Edwin Scherry Paul Schroder Gregory Shirek Tom Short Jeremy Smith Don Sweeney David Sweeting Richard Tanner Marcelo Valdes Peter Walsh Craig M. Wellman Matt Westerdale Kenneth P. White Shawn Worthington Alan Worthy Alex Wu

The following members of the individual balloting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. Michael Adams Ilanchezhian Balasubramanian Robert Barnett Thomas Bishop Frederick Brockhurst Chris Brooks Sheila Brown Rachel Bugaris John Byrne Keith Chow Donald Colaberardino Jerry Corkran Alireza Daneshpooy Glenn Davis Paul Dobrowsky Gary Donner

Randall Dotson Donald Dunn Marcia Eblen Carl Fredericks J. Travis Griffith Randall Groves Paul Hamer Scott Hietpas Werner Hoelzl R. Jackson Ben C. Johnson Laszlo Kadar John Kay Gael Kennedy Yuri Khersonsky Royce King

Jim Kulchisky Saumen Kundu Ed Larsen Duane Leschert Steven Liggio Kevin J. Lippert William Lockley Greg Luri William Maxwell John McAlhaney, Jr. William McBride Benjamin McClung L. Bruce McClung Larry McGuire John McQuilkin John Merando

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Copyright © 2014 IEEE. All rights reserved.


John Miller James Mitchem Daleep C. Mohla Daniel Mulkey Paul Myers Daniel Neeser Dennis Neitzel Arthur Neubauer Michael Newman Charles Ngethe Wheeler O’Harrow T. Olsen Lorraine Padden Richard Paes Sergio A. Panetta

Donald Parker David Parman Antony Parsons Christopher Petrola Jim Phillips Iulian Profir Nicholas Rafferty Charles Rogers Vincent Saporita Bartien Sayogo Edwin Scherry Robert Seitz Gregory Shirek Suresh Shrimavle Gil Shultz

James Smith Jeremy Smith Jerry Smith Gary Stoedter Peter Sutherland Wayne Timm James Tomaseski Luis Vargas John Vergis Craig M. Wellman Yingli Wen Kenneth P. White Tamatha Womack John Yale Jian Yu

When the IEEE-SA Standards Board approved this guide on 11 December 2013, it had the following membership: John Kulick , Chair David J. Law, Vice Chair Richard H. Hulett, Past Chair Konstantinos Karachalios, Secretary Masayuki Ariyoshi Peter Balma Farooq Bari Ted Burse Stephen Dukes Jean-Philippe Faure Alexander Gelman

Mark Halpin Gary Hoffman Paul Houzé Jim Hughes Michael Janezic Joseph L. Koepfinger* Oleg Logvinov Ron Petersen

Gary Robinson Jon Walter Rosdahl Adrian Stephens Peter Sutherland Yatin Trivedi Phil Winston Yu Yuan

*Member Emeritus

Also included are the following nonvoting IEEE-SA Standards Board liaisons: Richard DeBlasio, DOE Representative Michael Janezic, NIST Representative Julie Alessi IEEE-SA Content Publishing Lisa Perry IEEE-SA Technical Community Programs

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Introduction This introduction is not part of IEEE Std 1584.1-2013, IEEE Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard Calculation Study in Accordance with IEEE Std 1584™.

This guide has been developed by the Arc-Flash Hazard Calculations Working Group to support application of IEEE Std 1584™.

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Contents 1. Overview .................................................................................................................................................... 1 1.1 Scope ................................................................................................................................................... 1 1.2 Purpose ................................................................................................................................................ 1 2. Normative references.................................................................................................................................. 2 3. Arc-flash study general guidelines ............................................................................................................. 2 3.1 Scope of the arc-flash study ................................................................................................................. 2 3.2 Working distances ............................................................................................................................... 3 3.3 Shock hazard analysis .......................................................................................................................... 3 3.4 Results and recommendations ............................................................................................................. 3 4. Complexity of system ................................................................................................................................. 3 4.1 Simple system (single mode of operation)........................................................................................... 3 4.2 Complex system (multiple modes of operation) .................................................................................. 4 5. Data collection............................................................................................................................................ 4 5.1 Responsibility of data verification ....................................................................................................... 4 5.2 Data assumptions ................................................................................................................................. 5 5.3 Owner-supplied information ................................................................................................................ 5 6. Short-circuit study ...................................................................................................................................... 6 6.1 Verification of system.......................................................................................................................... 6 6.2 Number of calculations (scenarios) needed ......................................................................................... 6 6.3 Equipment evaluation .......................................................................................................................... 6 7. Overcurrent device clearing times/protective device coordination study ................................................... 7 7.1 Verification of existing study .............................................................................................................. 7 7.2 Complexity of system .......................................................................................................................... 7 7.3 Optimization of settings ....................................................................................................................... 7 8. Arc-flash hazard calculation location considerations ................................................................................. 7 9. Equipment labels ........................................................................................................................................ 8 9.1 Label content ....................................................................................................................................... 8 9.2 Label format ........................................................................................................................................ 8 10. Report, results, and recommendations ...................................................................................................... 9 10.1 Arc-flash study report ........................................................................................................................ 9 10.2 Recommendations ............................................................................................................................. 9 Annex A (informative) Bibliography ............................................................................................................11 Annex B (normative) Task matrix of work items for arc-flash analysis........................................................12 Annex C (normative) Equipment label checklist ...........................................................................................14 Annex D (normative) Deliverables for arc-flash study..................................................................................15

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IEEE Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard Calculation Study in Accordance with IEEE Std 1584™ IMPORTANT NOTICE: IEEE Standards documents are not intended to ensure safety, security, health, or environmental protection, or ensure against interference with or from other devices or networks. Implementers of IEEE Standards documents are responsible for determining and complying with all appropriate safety, security, environmental, health, and interference protection practices and all applicable laws and regulations. This IEEE document is made available for use subject to important notices and legal disclaimers. These notices and disclaimers appear in all publications containing this document and may be found under the heading “Important Notice” or “Important Notices and Disclaimers Concerning IEEE Documents.” They can also be obtained on request from IEEE or viewed at http://standards.ieee.org/IPR/disclaimers.html .

1. Overview

1.1 Scope This document provides guidance for the specification and performance of an arc-flash hazard calculation 1 study, in accordance with the process defined in IEEE Std 1584™. It outlines the minimum recommended requirements to enable the owner or its representative to specify an arc-flash study, including scope of work and associated deliverables.

1.2 Purpose This document defines the recommended minimum guidelines for performing a detailed arc-flash hazard calculation study (arc-flash study) based on IEEE Std 1584™. Use of this document should enable persons such as facility owners, contractors, equipment manufacturers, operations, safety, and electrical personnel as well as those responsible for the specification and/or the performance of the study to understand the 1

Information on references can be found in Clause 2.

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IEEE Std 1584.1-2013 IEEE Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard Calculation Study in Accordance with IEEE Std 1584

minimum scope of work and deliverables required. Additionally, by providing a detailed list of deliverable items, accurate proposals can be obtained.

2. Normative references The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and it s relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies. IEEE Std 1584™, IEEE Guide for Performing Arc-Flash Hazard Calculations.

2,3

3. Arc-flash study general guidelines The arc-flash study calculation procedure should be in accordance with IEEE Std 1584™, and any amendments including IEEE Std 1584a™ and IEEE Std 1584b™-2011. It is assumed that the equipment in the study is installed, operated, and maintained in accordance with manufactures’ instructions or industryrecognized standards. Three-phase ac circuits outside the range of IEEE Std 1584™ may be analyzed using other industry-accepted methods such as the Lee equations, which are also defined within IEEE Std 1584™. Other equipment not covered by IEEE Std 1584™ such as direct current, and overhead transmission and distribution systems, must either be excluded from the study or analyzed based on other industry-recognized methodology. Calculations can be run for single-phase equipment using IEEE Std 1584™, assuming it has three-phase service that will yield conservative results. This guideline is for existing systems, the expansion and modification to existing systems, and new construction.

3.1 Scope of the arc-flash study For each piece of equipment under study, the analysis is used to determine the estimated short-circuit and arcing currents, incident energy, and arc-flash boundary (AFB). As a minimum, the arc-flash study should encompass all equipment likely to require service or inspection while energized from the customer-owned service entrance equipment down through end user equipment rated 208 V nominal. IEEE Std 1584™ should be consulted for requirements for equipment rated less than 240 V (line-to-line). NOTE—Consult the latest edition of IEEE Std 1584™ for guidance.4

The results of the arc-flash study may also be used to develop recommendations such as changes to protective device settings in or der to reduce the incident energ y at locations where the i ncident energy level is deemed too high by the owner’s representative. Prior to the start of the study, it is recommended that the lead investigator interview all the stake holders to obtain a snap shot on the health of the electrical system. These individuals should include owners, facility engineers, electrical superintendents, and line foremen.

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The IEEE standards or products referred to in this clause are trademarks of The Institute of Electric al and Electronics Engineers, Inc. IEEE publications are available from The Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08854, USA (http://standards.ieee.org/). 4 Notes in text, tables, and figures of a standard are given for information only and do not contain requirements needed to implement this standard. 3

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3.2 Working distances Determine the working distance based on site practices and task to be performed. Default values in IEEE Std 1584™ may be used only if the owner does not have any requirements. If default values are used, this should be identified in the report as basis of calculations.

3.3 Shock hazard analysis 5

Shock hazard analysis results are not required on the label according to NFPA 70E [B6]. Specific shock hazard analysis information may be put on the label if required by the owner.

3.4 Results and recommendations Provide the results of the arc-flash analysis based on calculation(s) of the incident energy and AFB at each piece of electrical equipment under study. These values may be used to determine the appropriate levels of personal protective equipment required by qualified personnel working on or near the equipment, in keeping with the requirements of NFPA 70E, facility safety policies, and other applicable standards. In addition, the results are used to provide equipment labeling that contains information that can be used by the qualified person to perform the hazard risk assessment as required by the latest edition of NFPA 70E. The arc-flash study should be performed by, or under the direction of, a qualified person with the necessary knowledge about power system analysis and arc-flash hazard analysis or experience in performing power system analysis and arc-flash hazard analysis. It is recommended that engineers who are new to performing the studies obtain peer or third party reviews from a more experienced engineer in this specific subject. NOTE—Engineering licensing requirements of individual jurisdictions (states and/or provinces/nationalities) may require the analysis to be performed by, or under the direction of, a registered professional engineer.

4. Complexity of system The scope and level of detail of the arc-flash study are dependent on the complexity of the power distribution system under study. The levels of complexity and some typical characteristics are defined below.

4.1 Simple system (single mode of operation) A simple radial system is generally defined as a utility-owned service substation and/or transformers. Generally, the nominal secondary voltage is 600 V or less. Examples: Office buildings, commercial facilities, Reference: IEEE Std 141™-1993, Figure 2-1.

small

industrial,

and

institutional

systems.

5

The numbers in brackets correspond to those of the bibliography in Annex A.

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4.2 Complex system (multiple modes of operation) A complex system is generally defined as a customer-owned service transformer and/or secondary selective (double ended) substation. The system may include standby generators to provide power upon loss of utility service. Generally, the nominal service voltages are above 600 V and may include protective relaying, network systems, customer-owned primary substations, and customer-owned generation. Examples: Midsized industrial, institutional and large commercial facilities, systems with multiple secondary substations or delivery points, industrial complexes, data centers, hospitals. Reference: IEEE Std 141™-1993, Figure 2-5.

5. Data collection The arc-flash study must be based on accurate, up-to-date information. A single-line diagram is the preferred method of documentation of a power system. It generally represents existing conditions and equipment nameplate data for the portion of the system within the scope of the arc-flash study. This may require the person performing the study, or the facility’s owner, or owner’s representative to: 

  











Obtain any existing single-line drawings of the facility. Most software programs will create a simple diagram as data is entered. Verify and update existing single-line diagram to existing conditions. Verify and resolve any equipment labeling (naming) issues. Gather other system documentation, including transformer nameplate and test data, breaker or relay test reports, motor or generator data sheets, switchgear control drawings, copies of previous power system studies, conductor sizes types and lengths, etc. Obtain relay settings, current transformer ratios, circuit breaker trip unit settings and sensor sizes, fuse types and ampere ratings, and medium voltage motor equipment characteristics. Obtain generator short-circuit characteristics. Obtain wire and cable sizes, material of construction (aluminum or copper), cable construction (single or multi-conductor), raceway type, and length. Verify nomenclature to be used for equipment and all devices in the study with the owner. This includes abbreviations, etc. This should ensure proper naming convention before creation of the drawings, reports, and labels. Field inspections will likely be required to obtain and verify the required arc-flash study information. Where possible, it is usually helpful to work with personnel familiar with the facility’s power system. All site work should be performed in accordance with applicable facility safety requirements and applicable electrical work safety standards [B6]. In some cases, a partial or full system shutdown may be required to gather some information for safety reasons.

There may be other portions of the electrical power system at the facility to be studied that are not included in the scope of work; however, these portions of the system may affect the results of the system under the scope of the arc-flash study. When a facility is not performing an arc-flash study on its entire system, it will be necessary to obtain the available short-circuit currents and X/R ratios for sources of supply not included in the scope of the project at the terminals or buses where the project begins. It may also be necessary to obtain large motor short-circuit contribution data for large motors not included in the scope of the project at the appropriate terminals that are part of the project.

5.1 Responsibility of data verification Determination of which party(s) is to be responsible for verification of one-lines, creating one-lines, and other site data collection must be determined prior to the quoting of the arc-flash hazard study.

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If the facility owner does not provide facility data to the study engineer, the owner should provide qualified personnel to guide those responsible for the site data collection to the equipment locations to assist as required, and to open necessary equipment doors, locks, etc. to collect nameplate data and protective device settings. Switchboards, motor control centers (MCCs), panelboards, and distribution boards should be evaluated to determine if either the main internal overcurrent device or an upstream separately located device should be used for the calculation of the incident energy at these buses. Manufacturers should be encouraged to provide specific information upon request to aid in this evaluation. Responsibility for assessment of adequate segregation of main breakers from load buses or breakers in the same equipment to allow their use for arc-flash calculations must be clearly addressed in the scope of work for the study.

5.2 Data assumptions If data is not available or accessible for protective devices such as protective relays, current transformers (CTs), circuit breakers, and fuses, but reasonable assumptions can be made as to the device type or characteristics, these assumptions may be used. Care should be taken to ensure that the assumptions do not lead to under-reporting of available incident energy at downstream equipment. An alternate to this is to use the next overcurrent device upstream to define the clearing time where the data is known. NOTE—It is assumed that devices are installed and maintained per their manufacturers’ recommendations, are in good working order, and will trip according to their published time-current characteristic curves. The owner should inform the engineer responsible for the analysis if this is known to be untrue for any devices to be considered in the analysis. These devices should not be considered in the arc-flash study until they are in proper working order.

If actual utility fault current cannot be obtained from the utility company, then alternate scenarios should be modeled considering minimum and maximum values of utility fault current. These scenarios will provide a range of utility fault contributions that the study can be based on to account for potential changes in the utility system, and allowing for calculation of worst-case arc-flash levels inside the facility. Actual equipment data of bus gaps should be used if available to provide accurate results of the expected incident energy. Utilize default values provided in IEEE Std 1584™ only if actual values are not available. Document that the study is based on default values because actual bus gaps were not available.

5.3 Owner-supplied information The facility owner should provide to the qualified person(s) performing the arc-flash study the following data in writing: 

   

Electric utility company contact information. In many instances the owner may have to request the utility company data because utility companies may not provide that information to third parties without the owner’s permission. This information may include nominal voltage; normal, minimum, and maximum three-phase and single line-to-ground short-circuit currents; system X/R ratios; utility-provided overcurrent protection; or grounding configuration. Depending on the utility service configuration, transformer size, winding configuration, and impedance for utility-owned transformers may be needed. Modes of operation and system configuration. Existing single-line diagrams, if available. Relay and circuit breaker diagrams and test reports, if available. Past short-circuit, coordination, and arc-flash studies, including software data files, if available.

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6. Short-circuit study The arc-flash study should be based on an up-to-date short-circuit study that reflects existing conditions, alternate system configurations, and operating scenarios where applicable. In addition, minimum and maximum short-circuit current conditions should be evaluated to determine the effect on protective device clearing times and incident energy exposures.

6.1 Verification of system If an existing short-circuit study is available and is to be used for arc flash study, it must be verified by the owner that it accurately represents present conditions including utility short-circuit contributions, feeder sizes, types, and lengths, transformer sizes and impedances, motor and generator contributions, and system modes of operation. If a short-circuit study is not available, it should be performed based on applicable codes and standards.

6.2 Number of calculations (scenarios) needed For simple systems, two sets of calculations are needed. One is for the maximum available fault current from the utility with all large motors running. The second is the minimum available fault current from the utility with no large motors running. Utilities should be asked to provide the maximum and minimum number based on an up-to-date study of their system. For complex systems (multiple modes of operation), alternate switching scenarios must be selected and modeled to determine a set of possible available short-circuit currents. These results are then used to evaluate the effect on the overcurrent device clearing times and to determine the worst case arc-flash incident energy at each bus. Some locations in the system will exhibit the highest incident energy at high fault currents, while lower fault currents will result in higher incident energy values at other locations. Examples of modes of operation include alternate sources and paralleled sources switched in or out, double ended substation with tie open or closed, and standby generators running or shut down. The higher available fault current calculations should be based on all simultaneously operating large motors (greater than or equal to 50 hp) turned on, and the lower calculations should be based on no large motors running. Multiple incident energy calculations per bus are common, but engineering judgment should be applied to get an appropriate set of calculations for each bus. The modes of operation should be decided upon between the owner and the study provider.

6.3 Equipment evaluation While an arc-flash analysis requires that short-circuit levels throughout the power distribution system be calculated, evaluating the available short-circuit current compared to interrupting ratings of distribution equipment is recommended. In the course of gathering system information for the arc-flash study, information required for such evaluation of equipment is typically collected. The arc-flash study, therefore, presents a convenient opportunity to perform a full short-circuit analysis including evaluation of equipment ratings.

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7. Overcurrent device clearing times/protective device coordination study The arc-flash study requires up-to-date information regarding the clearing time of overcurrent protective devices that are under review and included in the scope of work of the study. This information can be obtained from the time-current curve of each device or from an up-to-date protective device coordination study (coordination study) that reflects existing conditions, alternate system configurations, and operating scenarios where applicable. The circuit breaker opening time should be added to the protective relay operating time for most medium- and high-voltage situations.

7.1 Verification of existing study If an existing coordination study is available, it must be verified that it represents existing conditions. If a coordination study is not available, it must be conducted based on applicable industry standards. NOTE—It is typically assumed that devices are in good working ord er and will trip according to their published timecurrent coordination curves. The owner should inform the engineer responsible for the analysis if this is known to be untrue for any devices to b e considered in the analysis.

7.2 Complexity of system For simple systems (simple radial feed), the arc-flash incident energy information can be derived manually from individual time-current curves or from commercially available software or spreadsheets. For complex systems (multiple modes of operation or larger radial systems) it is recommended that this arc-flash incident energy analysis is conducted with commercially available software.

7.3 Optimization of settings Since the information that is required for the coordination study is typically collected as part of the arcflash study data collection, the arc-flash study presents a convenient opportunity to perform the more detailed coordination analysis. If a full coordination study is performed, the study engineer should seek to identify areas where arc-flash incident energy reduction can be achieved through modification of existing device settings, particularly if coordination among devices can be maintained. In such cases, both the existing and recommended settings and the arc-flash levels based on the “before” and “after” settings should be documented in the study. Process continuity requirements for safety should be evaluated in the consideration of reduced arc-flash hazard levels thru faster overcurrent protective device functions.

8. Arc-flash hazard calculation location considerations It must be understood that a protective device can be counted on only to limit incident energy downstream from its source of supply and in a separate compartment or enclosure from the protective device. For example, a main circuit breaker in an MCC may or may not limit incident energy in the cubicle of the main circuit breaker because an arc-flash in that cubicle could escalate to a line side fault. Only the upstream protective device can be counted on to provide protection for that cubicle. The main circuit breaker could protect employees from an arc-flash in downstream sections of the MCC, switchboard, or control panel if the MCC, switchboard, or control panel construction has barriers to isolate the main breaker section. Using the same logic, main circuit breakers in switchboards and panelboards generally are not considered to provide arc-flash protection for their switchboard or panelboard because there is normally no complete 7




barrier between their line side connections and the possible location of an arc-flash in their enclosures. A qualified person with skills and knowledge of electrical equipment construction should make the determination of which overcurrent device is used for arc-flash incident energy calculations for a particular device. Reported results and the protective device they are based upon should take equipment configuration and construction into account.

9. Equipment labels As required by codes and regulations, labels should be created and affixed to electrical equipment that is defined in the scope of the study. This equipment should include as a minimum: switchgear, switchboards, panelboards, industrial control panels, meter socket enclosures, adjustable speed drives, machine control panels, and motor control centers. The scope may also include equipment such as, but not limited to, busway(s), bus plugs, fused and non-fused disconnect switches, and motor terminal boxes (not normally labeled). The responsibility for creation and installation of equipment labels must be clearly specified in the scope of the study. NOTE—Transformers (utility company and customer owned) are required as information to perform an arc-flash study; however, even though transformers do present an arc-flash hazard, they are not generally serviced while energized and thus they are not generally labeled.

9.1 Label content The label information required by NFPA 70E should be included on the label. See Annex C for options.

9.2 Label format Equipment labels should comply with the facility’s safety policies and with the requirements of the local authority having jurisdiction. They should be made of durable material suitable for the environment where they are to be applied. Labels for outdoor equipment should be UV resistant. Refer to ANSI Z535-4 for guidance. Information on labels should be based on worst case arc-flash incident energy data when there are multiple modes of operation. If different modes of operation yield significantly different levels of incident energy, two labels may be printed (normal and standby generation modes, or normal and maintenance modes involving different relay settings). Labels should depict the incident energy of the equipment at the time of the study. If changes to the system are recommended to lower incident energy, the labels reflecting these changes should not be installed until the changes have been implemented and verified. Temporary system or protective device setting changes (used by maintenance or engineering personnel to lower incident energy levels during maintenance activities) require administrative controls to be developed and integrated into the overall safety policy. For equipment with multiple sections or where rear or side access is possible, multiple labels may be required to ensure consistent understanding of the arc-flash risk at all possible access points. For plug-in busways, labels may be required at regular intervals along the length of the busway run (interval to be determined) or on the busway plugs themselves.

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10. Report, results, and recommendations The results of the arc-flash study should be incorporated into an organized report outlining the methodology, results, and recommendations of the study.

10.1 Arc-flash study report The arc-flash study report should include the following information as a minimum (see Annex D for deliverables checklist with options):    

 



Executive summary. Narrative describing the scope and results of the study and the methodology used. Description of modes of operation (power system) and details of the scenarios evaluated. Results of short-circuit analysis listing equipment that is applied above its short-circuit current rating, and recommendations if appropriate. Results and recommendations of time-current analysis, including time-current curves. Arc-flash spreadsheet: A tabulated form including a listing of all equipment that had arc-flash hazard values calculated as part of the study. This listing should include the calculated three-phase bolted fault current, arcing fault current, identity of overcurrent protection device with its opening time, working distance, arc-flash protection boundary, and incident energy. A tabulated form showing the worst case incident energy calculated for each bus and the associated mode of power system operation. Report may include incident energy calculated for each bus for each mode of operation. NOTE—This may be part of the arc-flash spreadsheet.







 



Documentation of all study input data, including utility available fault currents; cable sizes, types, and lengths; motor data; breaker types and settings; fuse sizes and types; etc. Up-to-date single-line diagram(s). Optionally, further detailed single-line diagrams including small motors, and 208 V/240 V panelboards may be included for use by maintenance personnel. Documentation of the software manufacturer, exact version of software used, and configuration settings used to do the study. List of assumptions that were made for cable lengths, CT ratios, transformer impedances, etc. Additional information may be included where it enhances understanding of the electrical system and arc-flash study. Advisory statements covering the impact of changes to the power system, including overcurrent protective devices or system operation and potential impact on arc-fl ash incident energies.

10.2 Recommendations Recommendations should be made to reduce the arc-flash incident energy where reasonably possible. These recommendations can be categorized into three groups based on complexity and cost. The three groups could include:   

Simple: Low cost options such as overcurrent device setting changes or fuse size/type changes. Moderate: Moderate cost solutions such as additional overcurrent protection. Detailed: Higher cost options such as installing new distribution equipment or retrofitting circuit breakers with new trip units or specialty relay control schemes to reduce arc-flash hazards. Moderate and detailed recommendations do not need to be complete but only address a probable approach to reduce the incident energy exposure. Detailed design is not able to be approximated at the time of specification and therefore cannot be expected to be complete until additional decisions are resolved by the owner and engineer.

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Where inadequate overcurrent device ratings (interrupting ratings) and equipment ratings (short-circuit current ratings) are reported, the study should provide recommendations on achieving proper overcurrent device and equipment ratings.

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Annex A

(informative) Bibliography Bibliographical references are resources that provide additional or helpful material but do not need to be understood or used to implement this standard. Reference to these resources is made for informational use only. [B1] ANSI Std Z534.4, Product Safety Signs and Labels. 6 [B2] CSA-C22.1, Canadian National Electric Code Part 1. 7 [B3] CSA-Z462, Workplace Electrical Safety Standard. [B4] IEEE Std 141™-1993, IEEE Recommended Practice for Electric Power Distribution for Industrial Plants. 8 [B5] NFPA 70®, National Electric Code®. 9 [B6] NFPA 70E, Standard for Electrical Safety in t he Workplace.

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ANSI publications are available from the Sales Department, American National Standards Institute, 25 West 43rd Street, 4th Floor, New York, NY 10036, USA (http://www.ansi.org/). 7 CSA publications are available from the Canadian Standards Association, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada, L4W 5N6 (http://www.csa.ca/). 8 IEEE publications are available from The Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08854, USA (http://standards.ieee.org/). 9 NFPA publications are available from Publications Sales, National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101, USA (ht tp://www.nfpa.org/).

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Annex B

(normative) Task matrix of work items for arc-flash analysis Data sheets for all data needed should be provided by the analysis provider. Data may be provided on marked-up single-lines or on data sheets. Use this task matrix to indicate who is to gather the data in the field and the quantity of each in the study. Refer to one-line if data is shown on the drawing. Task

Owner

Contractor or analysis provider

Other

Comments

General information Utility information— Short-circuit currents (both minimum and maximum based on u tility operations), X/R ratios Utility protective device for service, including mfgr., type, model, ratings, and setting Utility transformer or service entrance transformer (supply) with primary/secondary voltages, rating in kVA, % impedance, grounding, configuration Level of incident energy to initiate mitigation recommendations (see 10.2) Determination of the suitability for the potential use of main overcurrent devices located internal to MCCs, PDPs, switchgear, etc. for arc-flash calculations Single-line diagrams Available drawing number(s) Do they show relays/CTs and ratios/breaker/fuse mfgr/type/sizes/SC rating/ settings? Do they list wire material (Al or Cu), cable construction (1/C,3/C), sizes (AWG), raceway type (metallic or non-metallic), conductor lengths? Do they list motor ratings (for use in shortcircuit and arc-flash info)? Only those to be included in study need be shown. Verification that single-line diagrams are up-to-date. Power factor correction capacitors or filters Equipment to be studied and labeled Above 600 V: Switchgear Switches, fused cutouts, and circuit breakers Motor control centers

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Task


Owner

Other

Comments

Power factor correction capacitors or reactors 600 V down through 240 V equipment Switchgear Switchboards Transformers (not commonly labeled) MCCs Distribution panels Lighting panels Misc. power panels UPS (uninterruptable power supplies) ATS (automatic transfer switches) Adjustable speed drives Plug-in busways Separately mounted fused switches or circuit breakers Motor local disconnect switches (not commonly studied or labeled) Motor terminal boxes (not commonly studied or labeled) Utility meter boxes Other 208 V equipment to be st udied Switchboards Distribution panels VFDs Plug-in busways Lighting panels Misc. power panels Study data gathering tasks Fuses: size, manufacturer, model Circuit breakers: size, manufacturer, model, settings Protective relays: manufacturer, model, settings, and CT ratings Wire information: material (Al or Cu), cable construction (1/C,3/C), sizes (AWG), raceway type (metallic or non-metallic), conductor lengths Transformer: type, size in KVA, % impedance Motor ratings: FLA, LRA, SF, starting method Arc-flash analysis Calculations from commercial software Label printing Indoor labels (Yes-No) UV resistant labels (Yes-No) Busway labeling Label on busway at intervals Labels on busway plugs

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Annex C

(normative) Equipment label checklist

Item

Check box

Description

Label information required by NFPA 70E The following information may be included: Study date Study project number (if applicable) or other identifying information Name of firm or person performing study Equipment name Label location Upstream overcurrent device providing the arc-flash hazard protection. (Optional) NOTE—This is not necessarily the point to provide equipment lockout. Approach boundaries as defined by NFPA 7 0E Category of voltage rated gloves and related PPE Other information

NOTE—Labels should be provided to comply with the applicable electrical safe work practices standard. NFPA 70E is used above as an example.

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Annex D

(normative) Deliverables for arc-flash study This table can be used to determine required reporting options and who is performing tasks. Task

Owner


Other

Comments

Executive summary Study methodology narrative Arc-flash spreadsheet Separate listing of incident energy values for each mode of system operation studied Worst case listing of incident energy values by system operation calculations Report of as found and as recommended Documentation of study input data Electronic copy only Paper copy Documentation of software including version and library List of assumptions Single-line diagrams Listing of project scope only Added detail level for maintenance functions Equipment label Labels provided by Labels installed by Equipment evaluation report All devices listed Only devices applied above their short-circuit rating, voltage rating, or other criteria as agreed upon Overcurrent device coordination curves New facility: Recommended settings Existing facility: Existing settings Existing facility: Recommended settings Overcurrent device settings tabulation sheets New facility: Recommended settings Existing facility: Existing settings Existing facility: Recommended settings Other items

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IEEE 1584.1 - 2013 Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard

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