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Setting Standards for Exce1lenc.eTo: Current Holders of ANSI (84.1

-

1995From: NEMA Communications DepartmentDate: June 13,2005Subject: Reaffirmation of ANSI C8db.1-1995

The ANSI Board of Standards Revitw reaffirmed ANSI C84.1-1995 (R2001),"Electric Power Systemsand Equipment-Voltage Ratings (60Hertz)."

The new designator for this standarc is ANSI C84.1-1995 (R2005),"Electric Power Systems andEquipment-Voltage Ratings (60Her 2). "

Please insert the attached revisedtit1:

page into your standard.

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ANSI C84.1-1995 (R2005)

American National Standard

Electric Power Systems and Equipment-Voltage Ratings(60 Hertz)

Secretariat:

National Electrical Manufacl~urersAssociationApproved as an

American National Standards Institute, Inc.

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NOTICE AND DISCLAIMER

The information in this putllicationwas considered technically sound by the consensus ofpersons engaged in the development and approval of the document at the time it wasdeveloped. Consensusdc:esnot necessarily mean that there is unanimous agreementamong every person participating in the development of this document.

The National Electrical MarlufacturersAssociation (NEMA) standards and guidelinepublications, of which the tlocument contained herein is one, are developed through avoluntary consensus stancards development process. This process brings togethervolunteersandlor seeks olrt the views of persons who have an interest in the topic coveredby this publication. While '\IEMAadministers the process and establishes rules to promotefairness in the developmer ~tof consensus, it does not write the document and it does notindependently test, evaluate, or verify the accuracy or completeness of any information orthe soundness of any judgnents contained in its standards and guideline publications.NEMA disclaims liability for any personal injury, property, or other damages of any naturewhatsoever, whetherspecal, indirect, consequential, or compensatory, directly orindirectly resulting from thct publication, use of, application, or reliance on this document.NEMA disclaims and makcs no guaranty or warranty, express or implied, as to theaccuracy or completeness of any information published herein, and disclaims and makesno warranty that the inforrr ation in this document will fulfill any of your particular purposesor needs. NEMA does not undertake to guarantee the performance of any individualmanufacturer or seller's pr ]ducts or services by virtue of this standard or guide.In publishing and makingtliis document available, NEMA is not undertaking to renderprofessional or otherservic:es for or on behalf of any person or entity, nor is NEMAundertaking to perform an) duty owed by any person or entity to someone else. Anyoneusing this documentshoulcl rely on his or her own independent judgment or, asappropriate, seek theadvic:eof a competent professional in determining the exercise ofreasonable care in anygivb?ncircumstances. Information and other standards on the topiccovered by this publication may be available from other sources, which the user may wish

to consult for additional views or information not covered by this publication.

NEMA has no power, nor c oes it undertake to police or enforce compliance with thecontents of this document. NEMA does not certify, test, or inspect products, designs, orinstallations for safety or h~alth purposes. Any certification or other statement ofcompliance with any healtt or safety-related information in this document shall not beattributable to NEMA and i:;solely the responsibility of the certifier or maker of thestatement.

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American Approval of an American National Standard requires verification by ANSl that the- - - - - - - - - -requirements for due process, consensus, and other criteria for approval have been

National met by the standards developer.Standard Consensus is established when, in the judgment of Re ANSl Board of Standards

Review, substantial agreement has been reached by directly and materially affectedinterests. Substatltial agreement means much more than a simple majority, but notnecessarily unar~imity. Consensus requires that all views and objections beconsidered, and tliat a concerted effort be made toward their resolution.The use of AmerizanNational Standards is completely voluntary; their existence doesnot in any resped preclude anyone, whether he has approved the standards or not,from manufacturing, marketing, purchasing, or using products, processes, orprocedures not cclnformingto the standards.The American National Standards Institute does not develop standards and will in nocircumstancesgi\e an interpretation of any American National Standard. Moreover, noperson shall hav,? the right or authority to issue an interpretation of an AmericanNational Standarc in the name of the American National Standards Institute. Requestsfor interpretations should be addressed to the secretariat or sponsor whose name

appears on the tit e page of this standard.

CAUTION NOTlCE: This American National Standard may be revised or withdrawn atany time. The prt~ceduresof the American National Standards Institute require thataction be taken periodically to reaffirm, revise, or withdraw this standard. Purchasersof American National Standards may receive current information on all standards bycalling or writing the American National Standards Institute.

Published by

National Electrical Manufacturers /issociation1300 N. 17th Street, Rosslyn, Virginia 22209

CopyrightO 1996 National Electrical I anufacturersAssociationAll rights reserved

No part of this publication may be reproduced n anyform, in an electronic retrieval system or other\ vise,without prior written permission of the publishe-.

Printed in the United States of America

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ANSI C84.1-1995

CONTENTS

Page............................................................................................................................................Foreword ii

1 Scope and purpose ...........................................................................................................................11.1 Scope .......................................................................................................................................I1.2 Purpose ....................................................................................................................................I

2 Voltage ratings for 60-herz ele1:tric power systems ..........................................................................1.................................................................................................................................2.1 Definitions 1

2.2 Selection of nominal sy:. tern voltages.......................................................................................2..................................................................................................2.3 Explanation of voltage r.anges 3

2.4 Aplication of voltage rarges ......................................................................................................33 Voltage ratings for 60-hertz elctric equipment...................................................................................4

3.1 General .....................................................................................................................................43.2 Recommendation .....................................................................................................................4

Annex A Principal transformer connections to supply the system voltages of table 1 ............................7Annex B Illustration of voltage rarlgesof table 1 .....................................................................................8Annex C Voltage ratings for 60-h~?rtzelecltric utilization equipment ....................................................... 9

.................................................................................................Annex D Polyphase voltage unbalance 12Annex E Applicable standards ..............................................................................................................14

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ANSl C84.1-1995

Foreword (This Foreword is not pafl of American National StandardC84.1-1995)This standard supersedes American National Standard for Electric Power Systems and Equipment -Voltage Ratings (60 Hz), ANSl C84.1-1989. Standard nominal system voltages and voltage ranges shownin the previous standard remain unct-~angedin this standard. Revisions have been made to the text ofclauses 1.2(1), 1.2(6), 2.1.2. 1,2.1.2.2, 2.3, 3.2(2) and to the equation in D3. As in the previous standard,reference information on extra-high voltage conforms to American National Standard for Power Systems

-Alternating-Current Electrical Systems and Equipment Operating at Voltages above 230 kVNominal -Preferred Voltage Ratings, ANSl C92.2-1987.

In 1942, the Edison Electric lnstitute ilublishedthe document Utilization Voltage StandardizationRecommendations, EEI Pub. No. J-8.Based on that early document, a joint report was issued in 1949 bythe Edison Electric lnstitute (EEI Pub. No. R6) and the National Electrical Manufacturers Association(NEMA Pub. No. 117). This 1949 put ilicationwas subsequently approved as American National StandardEEI-NEMA Preferred Voltage Rating:; for AC Systems and Equipment, ANSl C84.1-1954.

American ~ationalStandard C84.1-1954 was a pioneering effort in its field. It not only made carefullyconsidered recommendations on voltage ratings for electric systems and equipment, but also contained aconsiderable amount of rnuch-neede j educational material.

After ANSl C84.1-1954 was preparec, the capacities of power supply systems and customers' wiringsystems increased and their unit volti~gedrops decreased. New utilization equipment was introduced andpower requirements of individual equipment were increased. These developments exerted an importantinfluence both on power systems anc equipment design and on operating characteristics.In accordance with American NationzilStandards lnstitute policy requiring periodic review of its standards,American National Standards Comm ttee C84 was activated in 1962 to review and revise AmericanNational Standard C84.1-1954, the Eclison Electric lnstitute and National Electrical ManufacturersAssociation being named cosponsor:; for the project. Membership on the C84 Committee represented awide diversity of experience in the elcctrical industry. To this invaluable pool of experience were added thefindings of the following surveys concucted by the committee:

(1) A comprehensive questionnaire on power system design and operating practices, includingmeasurement of actual service v ~ltages.(Approximately 65,000 readings were recorded, coming fromall parts of the United States and from systems of all sizes, whether measured by number ofcustomers or by extent of servic'?areas.)

(2) A sampling of single-phase distril~utiontransformer production by kilovolt-amperes and primaryvoltage ratings to determine relat~veuses of medium voltages.

(3) A survey of utilization voltages at motor terminals at approximately twenty industrial locations

The worth of any standard is measur ?dby the degree of its acceptance and use. After carefulconsideration, and in view of the stat(?of the art and the generally better understanding of the factorsinvolved, the C84 Committee concluc ed that a successor standard to ANSl C84.1-1954 should bedeveloped and published in a much zimplified form, thereby promoting ease of understanding and henceits acceptance and use. This resultec in the approval and publication of American National StandardC84.1-1970, followed by its supplemt!nt, ANSl C84.la-1973, which provides voltage limits established forthe 600-volt nominal system voltage.

The 1977 revision of the standard incorporated an expanded Foreword that provided a more complete

history of this standard's developmer t. The 1970 revision included a significantly more useful Table 1 (bydesignating "preferred" system voltages), the 1977 revision provided further clarity, and the 1982 revisionsegmented the system voltages into he various voltage classes.

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ANSl C84.1-1995

Suggestions for improvement of the :.tandard will be welcome. They should be sent to the NationalElectrical Manufacturers Association, 1300 N. 17th Street, Rosslyn, Virginia 22209.

This standard was processed and approved for submittal to ANSl by Accredited Standards Committee onPreferred Voltage Ratings for AC Sys,temsand Equipment, C84. Committee approval of the standarddoes not necessarily imply that all colnmittee members voted for its approval. At the time it approved thisstandard, the C84 Committee had thc! following members:DanielJ. Ward, ChairmanWalter J. Ros, Vice-ChairmanLawrence F. Miller, Secretary

Organizations Represented Name of Representative

Accredited Standards Committee on lilectric Lamps, C78 (Liaison) ...............A. RousseauAccredited Standards Committee on ndustrial Gas Equipment,Installations and Utilization, 283 (Liai:ion) .......................................................Gordon E. WillertAccredited Standards Committee on

National Electrical Code, C1 (Liaison: ..............................................................Arthur E. CoteAccredited Standards Committee on sJower Switchgear (Liaison)...................Charles T. ZegersAir Conditioning & Refrigeration lnstit ~ t e....................................................... Acton

George W. BrandtThomas A. Jacoby (Alt.)Leonard Van Tassel (Alt.)

Association of Home Appliance Man~facturers...............................................John T. WeizeorickCanadian Standards Association (Lia son)......................................................Representation Vacant)Certified Ballast Manufacturers Assoc iation ....................................................Robert BabcockDepartment of Water & Power, City o' Los Angeles .......................................Manuel De La Rosa

Robert Glickman (Alt.)

Electronic Industries Association ....................................................................John A. WyattElectric Light and Power Group ...................................................................M a w C. Mingoia (Alt.)

Michael PavukPaul RuganisDonnie TrivittDaniel J. Ward

Institute of Electrical and Electronics Iingineers ........................................Donald S. BreretonJ. J. BurkeLarry E. ConradStanley S. Kershaw (Alt.)Gary T. Smullin

National Electrical Manufacturers Association ................................................Robert G. BartheldDonald CorrigallRonald Gracyk (Alt.)

Loy HicksWalter J. Ros

: National Rural Electric Cooperative A jsociation .........................................Robert Bergland(Alt.)Rob Church

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ANSI C84.1-1995

.................Rural Electrification AdministrationU.3. Departmentof Agriculture Edmond W. Overstreet...............................Telephone Group ...............................................................Representation Vacant)

Tennessee Valley Authority .............................................................................Frank Lewis

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AMERICAN NATIONAL STANDARD C84.1-1995

for Electric Power Systems and Equipment-Voltage Ratings (60 Hertz)

1 Scope and purpose

1.1 Scope

This standard establishes nominal voltage ratings and operating tolerances for 60-hertz electric powersystems above 100 volts and througt- 230 kilovolts. It also makes recommendations to other standardizinggroups with respect to voltage ratings for equipment used on power systems and for utilization devicesconnected to such systems.

NOTE-For completeness, information onext a-high voltage systems(345kilovolts and higher) from American National Standardfor Power Systems-Alternating-CurrentEleo rical Systems and Equipment Operating at Voltages above230kV Nominal-Preferred Voltage Ratings, ANSI C92.2-1987, is also included as a footnote to table1 .1.2 Purpose

The purposes of this standard are to:

(1) Promote a better understanding of the voltages associated with power systems and utilizationequipment to achieve ovc!rall practical and economical design and operation

(2) Establish uniform nomen lature in the field of voltages(3) Promote standardization of nominal system voltages and ranges of voltage variations for

operating systems(4) Promote standardization of equipment voltage ratings and tolerances(5) Promote coordination of Ielationships between system and equipment voltage ratings and

tolerances(6) Provide a guide for future development and design of equipment to achieve the best possible

conformance with the nectds of the users(7) Provide a guide, with resoect to choice of voltages, for new power system undertakings and

for changes in old ones

2 Voltage ratings for 60-hertz electric power systems

2.1 Definitions

2.1.I system or power system: l' he connected system of power apparatus used to deliver electricpower from the source to the utilization device. Portions of the system may be under different ownership,such as that of a supplier or a user.

2.1.2 System voltage terms

2.1.2.1 system voltage: The root-mean-square (rrns) phase-to-phase voltage of a portion of analternating-current electric system. Ezch system voltage pertains to a portion of the system that isbounded by transformers or utilizatior equipment. (All voltages hereafter are rrns phase-to-phase orphase-to-neutral voltages.)

2.1.2.2 nominal system voltage: Th,?voltage by which a portion of the system is designated, and towhich certain operating characteristic:; of the system are related. Each nominal system voltage pertains toa portion of the system bounded by tr.~nsformersor utilization equipment.

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ANSI (284.1-1995

2.1.2.3maximum system voltage: l'he highest system voltage that occurs under normal operatingconditions, and the highest system vcltage for which equipment and other components are designed forsatisfactory continuous operation without derating of any kind. In defining maximum system voltage,voltage transients and temporary ove~voltagescaused by abnormal system conditions such as faults, loadrejection, and the like are excluded. t-lowever, voltage transients and temporary overvoltages may affectequipment operating performance anlj are considered in equipment application.2.1.2.4 service voltage: The voltage at the point where the electrical system of the supplier and theelectrical system of the user are connected.

2.1.2.5 utilization voltage: The voltage at the line terminals of utilization equipment.2.1.2.6 nominal uti lization voltage: The voltage rating of certain utilization equipment used on thesystem.

The nominal system voltages contained in table 1 apply to all parts of the system, both of the supplier andof the user. The ranges are given separately for service voltage and for utilization voltage, these normallybeing at different locations. It is recognized that the voltage at utilization points is normally somewhat lowerthan at the service point. In deferencc,to this fact, and the fact that integral horsepower motors, or airconditioning and refrigeration equipmsnt, or both, may constitute a heavy concentrated load on some

circuits, the rated voltages of such equipment and of motors and motor-control equipment are usuallylower than nominal system voltage. T i i s corresponds to the range of utilization voltages intable 1. Other utilization equipment is generally rated at nominal system voltage.

2.1.3 System voltage classes

2.1.3.1 low voltage: A class of nomir~ a lsystem voltages 1000 volts or less.2.1.3.2 medium voltage: A class of r hominalsystem voltages greater than I000volts and less than100 000 volts.

2.1.3.3 high voltage: A class of nom nal system voltages equal to or greater than 100 000 volts and equalto or less than 230 000 volts.

2.2 Selection of nominal systern voltagesWhen a new system is to be built or a new voltage level introduced into an existing system, one (or more)of the preferred nominal system voltaljes shown in boldface type in table 1 should be selected. The logicaland economical choice for a particular system among the voltages thus distinguished will depend upon anumber of factors, such as the charac:ter and size of the system.Other system voltages that are in substantial use in existing systems are shown in lightface type.Economic considerations will require 'hat these voltages continue in use and in some cases may requirethat their use be extended; however, hese voltages generally should not be utilized in new systems or innew voltage levels in existing system:;.

The 4160-volt, 6900-volt, and 13 800-volt three-wire systems are particularly suited for industrial systemsthat supply predominantly polyphase loads, including large motors, because these voltages correspond to

the standard motor ratings of 4000 volts, 6600 volts, and 13 200 volts, as is explained further in 2.1.2.6.Two of these system voltages are shown in boldface type to indicate that they should be used for thispurpose. It is not intended to recommend the use of these system voltages for utility primary distribution,for which four-wire voltages of 12 470Yl7200 volts or higher should be used.2.3 Explanation o f voltage ranges

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ANSI C84.1-1995

For any specific nominal system voltage, the voltages actually existing at various points at various timeson any power system, or on any g r o u ~ ~of systems, or in the industry as a whole, usually will be distributedwithin the maximum and minimum vc~ltagesshown in table 1. The design and operation of power systemsand the design of equipment to be supplied from such systems should be coordinated with respect tothese voltages so that the equipment will perform satisfactorily in conformance with product standardsthroughout the range of actual utilizat~onvoltages that will be encountered on the system. To further thisobjective, this standard establishes, f11reach nominal system voltage, two ranges for service voltage andutilization voltage variations, designated as Range A and Range B, the limits of which are given in table 1.These limits shall apply to sustained voltage levels and not to momentary voltage excursions that mayremit from such causes as switching ~perations,motor starting currents, and the like.2.4 Application of voltage ranges

2.4.1 Range A--service voltage

Electric supply systems shall be so designed and operated that most service voltages will be within thelimits specified for Range A. The occllrrence of service voltages outside of these limits should beinfrequent.

2.4.2 Range A-utilization voltageUser systems shall be so designed atid operated that with service voltages within Range A limits, mostutilization voltages will be within the linits specified for this range.

i Utilization equipment shall be designcidand rated to give fully satisfactory performance throughout this. range.

2.4.3 Range B-service and utili;i!ation voltagesRange B includes voltages above ancl below Range A limits that necessarily result from practical designand operating conditions on supply 01 user systems, or both. Although such conditions are a part of

: practical operations, they shall be limited in extent, frequency, and duration. When they occur, corrective.

measures shall be undertaken within a reasonable time to improve voltages to meet Range Arequirements.

Insofar as practicable, utilization equii~mentshall be designed to give acceptable performance in theextremes of the range of utilization vc Itages, although not necessarily as good performance as in RangeA.

It should be recognized that because of conditions beyond the control of the supplier or user, or both,there will be infrequent and limited periods when sustained voltages outside RangeB limits will occur.Utilization equipment may not operato satisfactorily under these conditions, and protective devices mayoperate to protect the equipment.

When voltages occur outside the l imisof Range B, prompt, corrective action shall be taken. The urgencyfor such action will depend upon many factors, such as the location and nature of the load or circuitsinvolved, and the magnitude and durz~tionof the deviation beyond Range B limits.

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ANSIC84.1-1995

3 Voltage ratings for 60-hertz electric equipment

3.1 General

Voltage ratings and other characteristics of the various classes of 60-hertz electric equipment areestablished in other standards. A part al list of these standards is given in AnnexE.For the principal types of electric utilization equipment, nameplate voltage ratings and the correspondingnominal system voltages to which theq are applicable are listed in tables C1,C2, and C3 in Annex C.Detailed tables for electric equipment other than utilization equipment are not included. Those requiringdetailed information on voltage rating:.; of these other types of equipment should consult the appropriatestandards or the manufacturers to en:;ure proper application.Review of the nameplate voltage ratirgs in Annex C and in current equipment standards listed in Annex Eindicates many inconsistencies in the relationships among equipment nameplate ratings and betweenthese ratings and nominal system vokages to which the equipment is applicable. For 120-volt basesystems, equipment voltage ratings a -evariously based upon 115 volts, 120 volts, and 125 volts. Thesame one of these bases is not alwabs used consistently for all equipment of the same general class.This standard includes information, a:; given in Annex D, to assist in the understanding about the effects

of unbalanced voltages on utilization c!quipmentapplied in polyphase systems.3.2 Recommendation

Insofar as practicable, whenever elec'.ricequipment standards are revised:(1) Nameplate voltage ratings should be changed as needed in order to provide a consistent relationship

between the ratings for all equipn ent of the same general class and the nominal system voltage onthe portion of the system on which they are designed to operate

(2) The voltage ranges for which equ pment is designed should be changed as needed in order to be inaccordance with the ranges shown in table 1.

The voltage ratings in each class of ulilizationequipment should be either the same as the nominalsystem voltages or less than the nomnal system voltages by the approximate ratio of 115 to 120.

4

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ANSI C84.1-1995

NOTES(a) Three-phase three-wire systems ,aresystems in which only the three-phase conductors are carried out

from the source for connection of loads. The source may be derived from any type of three-phasetransformer connection, groundedor ungrounded. Three-phase four-wire systems are systems inwhich a grounded neutral conductor is also carried out from the source for connection of loads. Four-wire systems in table 1 are desigr~atedby the phase-to-phase voltage, followed by the letter Y (exceptfor the 2401120-volt delta system;^, a slant line, and the phase-to-neutralvoltage. Single-phaseservices and loads may be supplied from either single-phase or three-phase systems. The principaltransformer connections that are used to supply single-phase and three-phase systems are illustratedin Annex A.

(b) The voltage ranges in this table are illustrated in Annex B.

(c) For 120-600-volt nominal system:;, voltages in this column are maximum service voltages. Maximumutilization voltages would not be expected to exceed 125 volts for the nominal system voltage of 120,nor appropriate multiples thereof 'or other nominal system voltages through 600 volts.

(d) A modification of this three-phase, four-wire system is available as a 1201208Y-voltservice for single-phase, three-wire, open-wyeappl cations.

(e) Certain kinds of control and prote2tiveequipment presently available have a maximum voltage limit of600 volts; the manufacturer or po,nrersupplier or both should be consulted to assure properapplication.

(f) Utilization equipment does not geierally operate directly at these voltages. For equipment suppliedthrough transformers, refer to limits for nominal system voltage of transformer output.

(g) For these systems Range A and RangeB limits are not shown because, where they are used as.

service voltages, the operating vcltage level on the user's system is normally adjusted by means ofi voltage regulations to suit their requirements.

: (h) Standard voltages are reprinted from American National Standard C92.2-1987 for convenience only.

(i) Nominal utilization voltages are fcr low-voltage motors and control. See Annex C for other equipmentnominal utilization voltages (or equipment nameplate voltage ratings.)

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ANSI C84.1-1995

Annex A(informative)

Principal transformer c:onnectionsto supply the system voltages of table 1(See figure Al)

Figure A1NOTES(a) The above diagrams show connections t ~ftransformer secondary windings to supply the nominal system voltages of table 1.

Systems of more than 600 volts are nonially three-phase and supplied by connections (3),(5) ungrounded, or (7). Systemsof 120-600 volts may be either single-phaseor three phase, and all of the connections shown are used to some extent forsome systems in this voltage range.

(b) Three-phase, three-wire systems may bt! solidly grounded, impedance grounded, or ungrounded but are not intended tosupply loads connected phase to-neutra (as the four-wire systems are).

(c) In connections (5) and (6) the ground mt~ybe connected to the midpoint of one winding as shown (if available), to one phaseconductor ("corner" grounded), or omitte entirely (ungrounded).

(d) Single-phase services and single-phase loads may be supplied from single-phase systems or from three-phase systems.They are connected phase-to-phasewhen supplied from three-phase, three-wire systems and either phase-to-phase orphase-to-neutral from three-phase, four- ire systems.

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ANSI C84.1-1995

Annex B(informative)

Illusfl:rationof voltage ranges of table 1Figure B1shows the basis of theRar~geA and Range B limits of table 1. The limits in table1 weredetermined by multiplying the limitssliown in this chart by the ratioof each nominal system voltage to the120-volt base. [For exceptions, seenllte (d) to figure BI.]

RANGiE A RANGE B

Figure B l

NOTES(a) These shaded portions of the ranges do not apply to circuits supplying lighting loads. See note 1 to table 1.

(b) This shaded portion of the range does not apply to 120-600-volt systems. See note (c) to table 1.

(c) The difference between minimum servict!and minimum utilization voltages is intended to allow for voltagedrop in the customer's wiring system. Th s difference is greater for service at more than 600 volts to allowfor additional voltage drop in transformat ons between service voltage and utilization equipment.

(d) The Range B utilization voltage limits in table1 for 6900-volt and 13800-volt systems are 90% and 110% of thevoltage ratings of the standard motors used in these systems and deviate slightly from this figure.

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Annex CVoltage ratings for 60-hertz electric utilization equipment(Refer to Annex E for a partial list of applicable standards.)

In tables C1 andC2 only representative categories of equipment are listed because thesheer number of present and prospective equipment makes it impractical to cover all of them.

Table C1-

Lamips,ballasts, and miscellaneous appliancesApplicable to All Nominal Eauioment

systemVoltages Containing ~ a m i ~ l a t eEquipment This Voltage(s) Voltage Rating

Lighting devicesI Incandescent lampsFixtures and ballasts for fluorescent and

high-pressure vapor lamps [Notes (a) and

Motor-operated appliances [Note (c)]Hair dryersClocks 120Dryers-clothes 120Fans 1201240, 24011 20, 208Y120Food mixersFood waste disposers

TimersVacuum cleaners 120Washers

ClothesDishes

Communication appliances

Projectors, silent and soundSmallLarge

PhonographsI Radios \Tape recordersTelevision

Heating and cooking apdances- . .~GnketsCooking appliances, table and counterHousehold- smallHousehold

-

largeCommercial-small

Commercial- large

Heaters, portable airHeating padsIrons

HandSoldering

Rangers-household1Water heaters

Tank- smallTank- large { 280 280

NOTES

(a) Lighting systems incorporating two ungrc unded wires for servicemay require special ballasts and auxiliaries.(b) Some ballasts are rated for use on more than one system voltage by use of taps or multiple primary windings.(c) Attention is called to the fact that under emergency conditions on electric systems, voltages below Range B of table 1 may be

encountered. This should be taken into account particularly in the design of motor -operated appliances for automatic startingand in the application of motors and control.

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Table C2-Heating, refrigeration, and air-conditioning equipmentApplicable to All Nominal Equipment

System Voltages Containing NameplateEquipment Phase This Voltage(s) Voltage Rating

Gas and oil furnaces and fractional hp 1{ ;:: 115coil units 230

Stokers 1 120 115

Refrigerators and freezers 1 120 115Room air conditioners 1 120 115

{ ;:: 208, (200)'230208,240 208/23OP, (20Ol23O)'P

Unitary air conditioners and heat pumpsMotor compressorsCondensing units 1 and 3 208 208, (200)'Water-chilling packages 1 and3 240 230Integral hp fan coil units, etc. 1 and3 208,240 208/23OP, (2001230)'PDuct and auxiliary electric heaters for 1 277 265

air-conditioning units and heat pumps 3 ' 480 4603 600 575

Electric furnaces and 3 240 2303 208 208, (200)'

Comfort heating

( 277 277Refrigerated drinking-water coolers 1 120 115Dehumidifiers 1 120 115

* Parenthetical values are under consideration for future design.P Slant between voltage values denotes 'either -or.'

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For the purposes of this Annex, the term 'motor control equipment' is used in a general sense andincludes some types of equipment classified as 'switchgear.' For applicable standards, see Annex E.The single-phase and three-phase motor and control voltage ratings shown in table C3 are well suited tothe nominal system voltages indicated. It should be generally understood that motors with these ratingsare to be considered as suitable for ordinaryuse on their corresponding system; for example, a 230-voltmotor is suited for use on a nominal 340-volt system. Operation of 230-volt motors on 208-volt systems isnot recommended because the utilization voltage encountered will commonly be below the -10% toleranceon the voltage rating for which the motor is designed.APPENDIX

Suitable measures should be taken by manufacturers and power suppliers to indicate to the purchaserthat equipment is intended to be used on the system whose nominal voltage is associated with, but mayboth be numerically equal to, the equipment nameplate voltage rating; for example, a motor and its controlrated 230 volts is intended for use on a nominal 240-volt system.

It should be noted that successful optmrationof a motor under given running conditions does notnecessarily mean that it will be able to start and accelerate all loads to which it may be applied underthese same operating conditions.

It should be recognized that synchron~usmotors, especially those rated 0.8 power factor, are reactivepower sources and consequently ma),increase the voltage at their terminals to higher values than thoseexperienced for induction motors und,l?rsimilar conditions.

TableC3-Motor and motor control equipmentApplicable to All All Motor and Motor Control Equipment Nameplate VoltageNominal System Ratings Containing This Voltage

Voltages Containing InteyalHorsepower Fractional HorsepowerThree-Phase Single-Phase Three-Phase Single-Phase

115 - 115

* Certain kinds of control and protective equipr lentpresently available have a maximum voltage limit of 600 volts; the manufactureror power supplier, or both, should be consultcd to ensure proper application.

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Annex DPolyphase voltage unbalance

D.l Introduction

Studies on the subject of three-phase voltage unbalance indicate that: (1) all utility-related costs required

to reduce voltage unbalance and all manufacturing-related costs required to expand a motor's unbalancedvoltage operating range are ultimately borne directly by the customer, (2) utilities' incrementalimprovement costs are maximum as the voltage unbalance approaches zero and decline as the rangeincreases, and (3) manufacturers' incremental motor-related costs are minimum at zero voltageunbalance and increase rapidly as tht?range increases.When these costs, which exclude mc tor-related energy losses, are combined, curves can be developedthat indicate the annual incremental cost to the customer for various selected percent voltage unbalancelimits.

The optimal range of voltage unbalance occurs when the costs are minimum.

Field surveys and statistics indicate tt~at:(1) Each motor rating is associatedwith a unique optimal range of voltage unbalance(2) These ranges vary from 0-2.5 percent to 0-4.0 percent voltage unbalance with the average at

approximately 0-3.0 percent(3) Approximately 98 percent of the tdectric supply systems surveyed are within the 0-3.0 percent

voltage-unbalance range, with 66 percent at 0-1.0 percent or lass

D.2 Recommendation

Electric supply systems should be de'jignedand operated to limit the maximum voltage unbalance to 3percent when measured at the electriz-utility revenue meter under no-load conditions.This recommendation should not be (:onstruedas expanding the voltage ranges prescribed in 2.4. If theunbalanced voltages of a polyphase :,ystem are near the upper or lower limits specified in table 1, RangeA or Range B, each individual phase ~oltageshould be within the limits in table 1.

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D.3 Definitions

Voltage unbalance of a polyphase system is expressed as a percentage value and calculated as follows:

0.7

I I 1 2 3 4 5

PERCENT VOLTAGE UNBALANCE

Figure D l -Derating factor

NOTE--See14.35 of NEMAMG 1-1993 for mire complete information about the derating factor.(max. deviation from average v)

Percent voltage u ibalance = 100 x(Average Voltage)

Example: with phase-to-phase voltagt?~of 230, 232, and 225, the average is 229; the maximum deviationfrom average is 4; and the percent urbalance is (100 X 4)/229 = 1.75 percent.D.4 Derating for unbalance

The rated load capability of polyphasf!equipment is normally reduced by voltage unbalance. A commonexample is the derating factor, from fi'aure Dl , used in the application of polyphase induction motors.D.5 Protection from severe voltage unbalance

User systems should be designed and operated to maintain a reasonably balanced load.In severe cases of voltage unbalance consideration should be given to equipment protection by applyingunbalance limit controls.

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Annex EApplicable standards

E. l List of standards

The following is a partial list of standards (by general number) for equipment from which voltage ratings

and other characteristics can be obta~ned.

IEquipment

Air-conditioningand refrigerating equipment n; mep plate voltagesStandard*

ARI 110I

Air filter equipmentAmmonia compressors and compressor units

IApplication, installat ion, and servicing of unitary systemsAutomatic commercial ice makersCable terminating devices (power)Central forced-air electric heating equipmentCentral-station air-handling unitsConnectors for electric utility applicationsDefinite purpose magnetic contactorsDehumidifiersElectrical measuring instruments

Electrical power insulatorsElectricity meteringForced circulation, free-delivery air coolers for refrigerationGas-fired furnacesIndustrial control apparatusInsulated conductors

LampsBactericidal lampsElectrical discharge lampIncandescent lamps

Lamp ballastsLow-voltage fusesLow-voltage molded-case circ breakers

Oil-fired furnaces

fMechanical transport refrigeration units

Packaged terminal air conditioners

Positive displacement refr igerant compressor . ~ n dcondensing unitsPower switchgear

Automatic circuit reclosersAutomatic line sectionalizersCapacitor switchesDistribution current-limiting fusesDistribution cutout and fuse linksDistribution enclosed single-pole air switcl esDistribution oil cutouts and fuse linksFused disconnecting switchesHigh-voltage air switchesManual and automatic station controlPower circuit breakersPower fusesRelays and relay systems

1 Secondary fusesSupervisory and associated telemetering ~!quipmentSwitchgear assemblies including metal enclosed busReciprocating water-chilling packages

Recreational vehicle air-conditioning equipmer tRemote mechanical draft air-cooled refrigerant condensersRoom air conditioners

EquipmentRoom fan-coil air conditioners

ARI 680ARI 510ARI 260ARI 810IEEE 48ARI 280ARI 430

ANSl C119.1ARI 780

ANSIIAHAM DH-1ANSl C39 Series

ANSl C29 SeriesANSl C12 SeriesAR I 420ANSl 221 SeriesANSllNEMA ICS SeriesANSIINFPA 70AElC SeriesICEA Series

ANSl C78 Series

ANSl C82 SeriesANSIINEMA FU1NEMA AB IARl I l l 0

CS 195

ARI 310ANSIIARI 520

ANSl C37 Series

ANSIIARI 590ARI 250ARI 460ANSIIAHAM RAC-1

Standard*ARI 441

Rotating electrical machinery-HCI~nuuc ;L IU I I t u~s x

*See list of organizations in Section E2. table continued on next page

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Cylindrical rotor synchronous generatorsSalient pole synchronous generator and cl~ndensersSynchronous motorsUniversal motors

Self-contained humidifiersSelf-contained mechanically refrigerated drinkiig-water coolersShunt power capacitorsSolenoid valves for liquid and gaseous flowStatic power conversion equipmentSurge arrestersTransformers, regulators, and reactors

Arc furnace transformersConstant-current transformersCurrent-limiting reactorsDistribution transformers, conventional su )way-type

Dry typeInstrument transformersPower transformersRectifier transformersSecondary network transformers

SpecialtyStep-voltage and induction-voltage re! ulators

Three-phase load-tap-changing transformersUnit ventilators ARI 330Unitary air-conditioning equipment ARI 210Commercial and industrial unitary air-conditionng equipment ANSIIARI 360Unitary heat-pump equipment ARI 240Wiring devices ANSIC73 Series*See list of organizations in Section E2.

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ANSl C50 Series andNEMA MG 1

ANSIIARI 620ANSIIARI 1010ANSIIIEEE 18

ARI 760ANSl C34

ANSl C62.61 &NEMA LA 1

ANSl C57 SeriesANSllNEMA ST 20

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E.2 Organizations Referred to in Section E.l

AElC

AMCA

ANSI

ARI

CS

IBR*

ICEA

NEMA

*Institute of Boiler and Radiator Manufacturers.

Copyright N a l i i ~ lElectrical Manufacturers AssociationPmvidedby IHSunder license with NEMANo reprodmionor networkingperminedwithout l~censefmrnIHS

Association of Edison Illuminating CompaniesP.O. Box 2641Birmingham, AL 35291-0992

Association of Home Appliance Manufacturers

20 North Wacker DriveChicago, IL60606

Air Movement and Control Association30 West University DriveArlington Heights, IL.60004

American National Standards Institute, Inc11 West 42nd Street, 13th FloorNew York, N.Y. 10036

Air Conditioning and Refrigeration lnstitute4301 N. FairfaxDrive; Suite 425Arlington, VA 22203

Commercial StandardsOffice of Commodity StandardsNational lnstitute of Standards and Technology,

U.S. Department of CommerceGaithersburg, MD20899-0001

Hydronics lnstitute35 Russo Place,P.O. Box 218Berkeley Heights, NJ 07922

The lnstitute of Electrical and ElectronicsEngineers, Inc.

445 Hoes LanePiscataway, NJ 08855

Insulated Cable Engineers AssociationBox PSouth Yarmouth, MA 02664

National Electrical Manufacturers Association

1300 North 17th Street; Suite 1847Rosslyn, VA 22209

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ANSI C84.1-1995

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