1、NEMA Standards PublicationNational Electrical Manufacturers AssociationANSI C12.20-2015Electricity Meters 0.1, 0.2, and 0.5 Accuracy ClassesANSI C12.20-2015 American National Standard for Electricity Meters0.1, 0.2, and 0.5 Accuracy ClassesNOTICE OF ADOPTION ANSI C12.20 was adopted and is approved f
2、or use by the Department of Defense (DoD). The National Electrical Manufacturers Association has furnished the clearance required by existing regulations. Copies of the document are stocked at the Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, for
3、 issue to DoD activities only. All other requestors must obtain copies from NEMA. ANSI C12.20 was adopted by the Dominica Bureau of Standards and is approved for use by the Commonwealth of Dominica. Secretariat: National Electrical Manufacturers Association Approved: February 17, 2017 American Natio
4、nal Standards Institute, Inc. 2017 National Electrical Manufacturers Association NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed. Consensus does
5、 not necessarily mean that there is unanimous agreement among every person participating in the development of this document. ANSI standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus standards development process. This proc
6、ess brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process to promote fairness in the development of consensus, it does not write the document, and it does not independently test, evaluate, or
7、 verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compens
8、atory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, expressed or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty that th
9、e information in this document will fulfill any of your particular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or sellers products or services by virtue of this standard or guide. In publishing and making this document available, NEMA is not
10、 undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice
11、of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or information not covered by t
12、his publication. NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any health-
13、 or safety-related information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. ANSI C12.20-2015 Page i AMERICAN NATIONAL STANDARD Approval of an American National Standard requires verification by The American National S
14、tandards Institute, Inc. (ANSI) that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. An American National Standard implies a consensus of those substantially concerned with its scope and provisions. Consensus is established when,
15、 in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly, and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered a
16、nd that a concerted effort be made toward their resolution. The existence of an American National Standard does not in any respect preclude anyone, whether s/he has approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to
17、the standards. It is intended as a guide to aid the manufacturer, the consumer, and the general public. The American National Standards Institute, Inc., does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have th
18、e right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute, Inc. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on this title page. CAUTION NOTICE: This American National
19、 Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute, Inc. require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by
20、 calling or writing the American National Standards Institute, Inc. Published by National Electrical Manufacturers Association 1300 North 17thStreet, Suite 900 Rosslyn, Virginia 22209 2017 National Electrical Manufacturers Association All rights, including translation into other languages, reserved
21、under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American copyright conventions. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior wri
22、tten permission of the publisher. Printed in the United States of America ANSI C12.20-2015 Page ii 2017 National Electrical Manufacturers Association Foreword (This foreword is not part of American National Standard C12.20) This American National Standard establishes acceptable performance criteria
23、for electricity meters. Accuracy class designations, current class designations, voltage and frequency ratings, test current values, service connection arrangements, pertinent dimensions, form designations, and environmental tests are covered. The existing C12.20 standard has been revised with the i
24、ntent to bring it up to date in an industry that is changing dramatically because of both technology and regulatory matters. Major changes in this edition include testing under harmonic conditions, addition of a 0.1% accuracy class, clarification that non-Blondel applications are not covered by this
25、 standard, and addition of specifications for the optical test output port. In memoriam to Herman Millican: Herman had a passion for standards and members of SC16 felt fortunate to know and learn from him. Suggestions for improvement to this standard are welcome. They should be sent to: National Ele
26、ctrical Manufacturers Association Senior Technical Director 1300 North 17th Street Suite 900 Rosslyn, VA 22209 This standard was processed and approved for submittal to ANSI by Accredited Standards Committee for Electricity Metering, C12. At the time the committee approved this standard, the C12 Mai
27、n Committee had the following members: Shannon Edwards, Chairperson ANSI C12/SC16 Tom Nelson, Chairperson ANSI C12 Paul Orr, Secretary Organization Represented Name of Representative Organization Represented Name of Representative General Interest Elevate Energy L. Kotewa NIST T. Nelson ERCOT EnerNe
28、x LLC D. Tucker A. Snyder Power Measurements, LLC Tucker Engineering W. Hardy R. Tucker Future DOS R rated voltage 1%; rated frequency 1 Hz; test amperes 1%; and unity power factor (0 2). The meter shall be stabilized at ambient temperature before performance tests are made. The meter performance un
29、der the test conditions above shall be as close as practical to zero error and in no case shall exceed 0.2% error for accuracy class 0.5, 0.1% error for accuracy class 0.2, or 0.05% error for accuracy class 0.1. Polyphase loading may be used for calibration type tests listed in Table 6. A meter may
30、meet the requirements of tests 18, 13 and 3944 using either series-parallel loading or polyphase loading. The calibration type tests described in tests 18, 13 and 3944 shall all be performed using the same loading method, either series-parallel or polyphase, once one is selected for use. ANSI C12.20
31、-2015 Page 6 2017 National Electrical Manufacturers Association 5.5.2 Loading for Accuracy Tests Unless otherwise specified, accuracy tests may be done with either series-parallel loading or polyphase loading; however, polyphase loading is recommended for all multi-element meters. For series-paralle
32、l loading, the meter shall be tested with the voltage circuit(s) effectively in parallel and with the appropriate current circuit(s) effectively in series. For polyphase loading, the meter shall be tested with voltage and current phase angles similar to actual service installations as described (pol
33、yphase loading) in Table 3. Polyphase loading will be mandatory for testing of polyphase meters effective January 1, 2020. When polyphase loading is used, the appropriate loading will depend on the meter configuration (meter Form). Accuracy tests done with polyphase loading shall pass for Typical Lo
34、ading configurations as shown in Table 3. If the meter is certified for use with an alternate loading configuration, then for those tests designated in the last column of Table 6, testing shall be performed using all Alternate Loading configuration(s) particular to the type description shown in Tabl
35、e 3. The internal meter connections for these Forms Designations are provided in ANSI C12.10. Table 3 Polyphase Service Loading for Use on Accuracy Tests Description Form Designations Typical Loading Alternate Loading Two-Element, Self Contained 12S, 13S, 25S, 32S, 13A Three wire, Network Three wire
36、, 3 Phase, delta Three wire, 1 Phase Two-Element, Transformer Rated 5S, 26S, 35S, 45S, 56S, 5A, 35A, 45A, 66S Three wire, 3 Phase, delta Three wire, 1 Phase Three wire, Network Three-Element, Self Contained 16S, 16A Four wire, wye Four wire, delta Three-Element, Self Contained 17S, 17A Four wire, de
37、lta None Three-Element, Transformer Rated 11S, 11A Four wire, delta None Three-Element, Transformer Rated 9S, 10S, 39S, 9A, 10A, 48A Four wire, wye Four wire, delta Polyphase loading may be either ABC or CBA phase sequence. For ABC phase sequence, the voltage and current phase angles for unity power
38、 factor are shown in Table 4. Table 5 shows phase angles for CBA phase sequence. For both tables, the angles represent the amount that phasors lag the A Phase Voltage. Table 4 ABC Phase Sequence, Current the meter shall show no damage and shall operate correctly in accordance with the requirement of
39、 the standard. Any change in energy and power quantities shall be limited to 1 least significant digit displayed. 5.5.5.2 Test Number 15: Insulation Refer to subclause 4.7.3.1 Test No. 15: Insulation of ANSI C12.1. 5.5.5.3 Test Number 16: Voltage Interruptions Test Refer to subclause 4.7.3.2 Test No
40、. 16: Voltage interruptions test of ANSI C12.1. 5.5.5.4 Test Number 17: Effect of High Voltage Line Surges Refer to subclause 4.7.3.3 Test No. 17: Effect of high voltage line surges of ANSI C12.1. 5.5.5.5 Test Number 18: Effect of External Magnetic Field Refer to subclause 4.7.3.4 Test No. 18: Effec
41、t of external magnetic field of ANSI C12.1 except that Table 20 (below) is to be used in place of Table 21 in ANSI C12.1. Table 20 Effect of External Magnetic Field Condition Current In Amperes Position of Conductor From ANSI C12.1 Maximum Deviation In % From Reference Performance Current Class Accu
42、racy Class 2 10 20 100 200 320 0.5 0.2 0.1 Reference for Conditions (1), (2), and (3) 0.025 0.25 0.25 1.5 3 5 Reference Reference Reference Condition (1) 0.025 0.25 0.25 1.5 3 5 Condition (1) in Paragraph 4.7.3.4 1.0 1.0 1.0 Condition (2) 0.025 0.25 0.25 1.5 3 5 Condition (2) in Paragraph 4.7.3.4 1.
43、0 1.0 1.0 Condition (3) 0.025 0.25 0.25 1.5 3 5 Condition (3) in Paragraph 4.7.3.4 1.0 1.0 1.0 ANSI C12.20-2015 Page 18 2017 National Electrical Manufacturers Association 5.5.5.6 Test Number 19: Effect of Variation of Ambient Temperature This test shall be applied to a minimum of three meters. The m
44、eters shall be placed in a space with a temperature of 23C 5C and allowed to stand for no less than 2 hours with the voltage circuits of the meters energized. Reference performance at each of the loads specified in Table 21 shall be obtained after operating the meters for 1 hour at the specified loa
45、d. The meters shall then be operated and tested at each of the following conditions: a) Conditions (1) through (6): These tests shall be conducted by placing the meter in a space with a temperature of 50C 5C. After energizing the voltage circuits of the meters for no less than 2 hours, the appropria
46、te test currents at the power factors listed for conditions (1) through (6) of Table 21 shall be sequentially applied to the meters. Each condition shall be maintained for a period of at least 1 hour before performing tests to determine the deviation from reference performance. b) Conditions (7) thr
47、ough (12): Repeat conditions (1) through (6), respectively, but place meters in a space with a temperature of 20C 5C. The effect of variation of temperature upon the performance of the meters shall not exceed that specified in Table 21. Nominally available voltage and current can be used for the dur
48、ation of this test when the metering device is not undergoing the specified accuracy test. ANSI C12.20-2015 Page 19 2017 National Electrical Manufacturers Association Table 21 Effect of Variation of Ambient Temperature Condition Current in Amperes Power Factor Ambient Temperature Max. Deviation in %
49、 from Reference Performance at Nominal Temperature Difference Current Class Accuracy Class 2 10 20 100 200 320 0.5 0.2 0.1 Reference performance for Conditions (1) & (7) 0.025 0.25 0.25 1.5 3 5 1.0 23C 5C Reference Reference Reference Reference performance for Conditions (2) & (8) 0.25 2.5 2.5 15 30 50 1.0 23C 5C Reference Reference Reference Reference performance for Conditions (3) & (9) 1 5 10 50 100 150 1.0 23C 5C Reference Reference Reference Reference performance for Conditions (4) & (10) 0.05 0.5 0.5 3 6 10 0.5 lag 23
