1、Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproducti
2、on or networking permitted without license from IHS-,-,-Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD-NEMA CLZOB-ENGL L98L b470247 0524084 2T4 D ANSI C12.8-1981(R-
3、l997) AMERICAN NATIONAL STANDARD For Test Blocks and Cabinets for Installation of Self-Contained A-Base Watthour Meters Secretariat National Electrical Manufacturers Association American National Standards Institute Reaffirmed August 20,1997 Copyright National Electrical Manufacturers Association Pr
4、ovided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-American National Standard Approval of an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other criteria for approval
5、 have been met by the standards developer. Consensus is established when, 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 una
6、nimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standards or not,
7、from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shal
8、l have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: Th
9、is American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on al
10、l standards by calling or writing the American National Standards Institute. Published by National Electrical Manufacturers Association 1300 N. 17th Street, Rosslyn, Virginia 22209 O Copyright 1999 by the National Electrical Manufacturers Association. All rights including translation into other lang
11、uages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American Copydght Conventions. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, wi
12、thout prior m-tten petmission of the publisher. Printed in the United States of America ii Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD-NEMA CLZ*B-ENGL 1981 64702
13、47 052408b 077 ANSI C12.8-1981 (R-1997) Contents Foreword v Section 1 Scope 1 Section 2 Definitions . 1 2.1 Cabinet, test block 1 2.2 Connector . 1 2.3 Disconnect 1 2.4 Test block . 1 Page Section 3 Standard ratings 1 3.1 Current 1 3.2 Voltage 1 Section 4 General requirements . 1 4.1 Spacings . 1 4.
14、2 Temperature rise 1 4.3 Assembly bolts 2 4.4 Connectors 2 4.5 Connector nuts 2 4.6 Test clips . 2 4.7 Barriers . 2 4.8 Disconnect device . 2 4.9 Material of base 2 4.1 O Mounting holes 3 Section 5 Test-block dimensions and configurations . 3 5.1 Dimensions . 3 5.2 Test-block figures . 3 Section 6 T
15、est-block-cabinets . 9 6.1 Dimensions for indoor test-block cabinets 9 6.2 Cabinet cover 9 6.3 Cabinet material 9 6.4 Cabinet construction . 9 . 111 Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted wi
16、thout license from IHS-,-,-ANSI C12.8-1981 (R-1997) Foreword for the Installation of Self-Contained A-Base Waithour Meters.) This standard covers the dimensions and functions of test blocks and cabinets used with self-contained A- base watthour meters. mis foreword is not part of ANSI c12.8-1981 (R1
17、997), American National Standard for Test Blocks and Cabinets This standard supersedes the requirements of the former AEIC-EEI-NEMA Standard for Test Blocks and Cabinets for the Installation of Self-contained “A“ Base Watthour Meters, MSJ-8-1951, NEMA Pub No 103- 1951. Suggestions for improvement to
18、 this standard are welcome. They should be sent to the American National Standards Instiute, 1430 Broadway, New York, NY 10018. This standard was processed and approved for submittal to ANSI by American National Standards Committee on Electricity Metering, C12. Committee approval of the standard doe
19、s not necessarily imply that all committee members voted for its approval. At the time it approved this standard, the C12 Committee had the following members: Nile Oldham, Chair Khaled Masri, Secretary Organization Represented Name of Representative Electric Light and Power Group (The Association of
20、 Edison Illuminating Companies and the Edison Electric Institute) . J. McEvoy T. Vahlstrom J. Mining L. Pananen Institute of Electrical and Electronics Engineers . H. Millican National Institute of Standards and Technology . N. Oldham National Electrical Manufacturers Association. . W. Germer T. C.
21、Drew F. A. Marta Underwriters Laboratories . R. Breschini Rural Electrification Administration . S. Jones Florida Public Service Commission J. Ruehl City of Los Angeles . C. Gomer V Previous page is blank. Copyright National Electrical Manufacturers Association Provided by IHS under license with NEM
22、ANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMERICAN NATIONAL STANDARD ANSI CI 2.8-1 981 (R-I 997) American National Standard for Test Blocks and Cabinets for Installation of Self-contained A-Base Watthour Meters 1 Scope This standard covers the dimensions and
23、 functions of test blocks and cabinets used with self-contained A- base watthour meters. 2 Defin it ions 2.1 Cabinet, test block An enclosureto house a test block and wiring for a bottom-connected watthour meter. 2.2 Connector A coupling device employed to connect conductors of one circuit or transm
24、ission element with those of another circuit or transmission element. 2.3 Disconnect A conductor, bar, or nut used to open an electrical circuit for isolation purposes. 2.4 Test block A terminal block with provisions for bypassing an electrical load to isolate a meter or other device for test purpos
25、es. 3 Standard ratings 3.1 Current Ratings shall be 1 O0 A and 200 A. 3.2 Vobge Ratings shall be 300 V and 600 V. 4 General requirements 4.1 Spacings Spacings shall be as indicated in Table 1. Grounded metal includes the enclosure and any metal in permanent electrical connection with the enclosure.
26、4.2 Temperature rise The temperature rise of currentcarrying parts shall not exceed 55OC above an ambient temperature of 25OC at 100% of rated current. 1 Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitt
27、ed without license from IHS-,-,-ANSI C12.8-1981 (R-1997) - (A) 1 O0 4.3 Assembly bolts AWG Wire Size No 8 to No 1/0 Assembly bolts shall be of brass, cadmium-plated steel, or the equivalent and shall have a thread No 12-24. NOTE-The cadmium coating shall be not less than 0.0005 inch thick in order t
28、o conform with type NS, as described in ANSI/ASTM A165-80, Specification for Electrodeposited Coatings of Cadmium on Steel. 4.4 Connectors 200 Connectors shall be the solderless type and accommodate the following wire sizes: Device Rating No 1/0 to 250 kcmil Connector nuts shall be of brass, cadmium
29、-plated steel, or other materials suitable for the purpose, and shall have a 0.500 inch short diameter across flats (see Note in 4.3). 4.6 Test clips Means for safely attaching test clips shall be provided on both sides of the disconnecting device. Means may consist of one (1) grooved connector nuts
30、 suitable for attaching 40 A Mueller copper test clips or two (2) extra nuts for attaching lugs of jumpers. Table I - Minimum Spacings Minimum Spacings from Live Parts to Voltage Parts of Opposite Polaritya Grounded Metalb Between Parts Over Through Over Through Involved (V) Surface (in) Air (i$ Sur
31、face (in) Air (in) 0-300 0.750 0.375 0.500 0.375 301-600 1.250 0.750 I .o00 0.500 a) b) c) Through-air and over-surface spacings of 0.375 inch, to be acceptable at other than wiring terminals, to cast-metal enclosure or to grounded metal where indentation or deformation of the overall enclosure will
32、 not afect spacings, shall withstand a dielectric strength test at 6000 V, 60 M, for 1 min. Through-air and over-surface spacings of 0.3475 inch between parts of opposite polanty, to be acceptable at other than wiring terminais, shall withstand a dielectric strength test at 6000 V, 60 Hz, for 1 min.
33、 300 V spacings shall apply in a 600 V test block if the phaseto-neutral potential does not exceed 300 V for spacings (1) from neutral to phase-potential parts and (2) from neutral to grounded metal. 4.7 Barriers Barriers may be an integral part of the base or a separate part fastened to the base. 4
34、.8 Disconnect device The disconnect device may consist of links, raising nuts, or some other device of a satisfactory design. 4.9 Material of base The matenal of the base shall be suitable for the sole support of uninsulated current-carrying parts. 2 Copyright National Electrical Manufacturers Assoc
35、iation Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI C12.&1981 (R-1997) 4.O Mounting holes Mounting holes shall be centered between the top and bottom of the test block. Clearance shall be provided for mounting screws N
36、o 10-32. 5 Test-block dimensions and configurations 5.1 Dimensions All drawings are dimensioned in inches. To convert to the metric system in millimeters, multiply the dimensions in inches by 25.4. The resulting metric dimensions shall be rounded to the nearest 0.02 mm. 5.2 Test-block figures Curren
37、t Rating (A) Connection Sequence Figure 1 O0 Line-Load 1 1 O0 Line-Line-Line-Load-Load-Load 2 200 Line-Load 3 200 Line-Load, alternate construction 4 Neutral block 5 3 Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or netw
38、orking permitted without license from IHS-,-,-STD-NEMA CLZmB-ENGL I4781 W 6470247 0524091 434 W ANSI C12.8-I981 (R-1997) r- -1 - 3.000 - , L- t.500 r- -7 v 8 0.250 .- r- . fl If 0.375 VJ I I i 3 t -1 - 0.375 i.500 1 5.500 1 c 0.250 TOLERANCE 0.016 ON ANY SINGLE DIMENSION 0.032 ON ANY CUMULATIVE DIME
39、NSIONS ALL DIMENSIONS IN INCHES 0.250 -f M - Terminals for rigid bypass jumpers. These can be a part of line-terminai connectors. Figure 1 - I00 ampere test-block line-load sequence of connections 4 Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot fo
40、r ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI C12.8-1981 (R-1997) t 4 0.250 TOLERANCE n 0.016 ON ANY SINGLE DIMENSION 0.032 ON ANY CUMULATIVE DIMENSIONS p- I?- ALL DIMENSIONS IN INCHES I 11 O. 250 t ?i- - M -Terminals for rigid bypass jumpers. These can be There s
41、hall be 0.025 inch minimum spacing over lha a part of line-terminai connectors. parts with largest conductor in terminal. Figure 2 - I00 ampere test-block line-line-line-load-load-load sequence of connections Copyright National Electrical Manufacturers Association Provided by IHS under license with
42、NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD-NEMA CL2.B-ENGL 1981 6470247 0524093 207 I- -4 -L I - L- y r- - -? -1 -3 L- - ANSI C12.8-i981 (R-1997) f O 1 250 r 1.500 1.500 r L 5.500 r i.500 I -1 -Ylo.210 n n - 0: U n m E a - TOLERANCE 0.016 ON ANY SINGL
43、E DIMENSION 0.032 ON ANY CUMULATIVE DIMENSIONS ALL DIMENSIONS iN INCHES 5- II I t 7 0.500 hl - Terminals for rigid bypass jumpers. These can be There shall be 0.025 in& mimimum spacing over live a part of line-terminal connectors. parts with krgest conductor in terminal. Figure 3 - 200 ampere test-b
44、lock line-load sequence of connections 6 Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STDmNEflA CLZ-8-ENGL 1981 m 6470247 0524094 143 = ANSI C12.-1981 (-i997) TOLERANC
45、E 0.016 ON ANY SINGLE DIMENSION 0.032 ON ANY CUMULATIVE DIMENSIONS ALL DIMENSIONS M INCHES NOTES: (1) The strike distance between upper and lower bus sections shall not be les than 0.25inch when the shorting nut is backed off. (2)The circuit-ciwing nut shall be a hexagomi nut 0.625 inch across flab
46、with a piate copper washer rt- tiched and hail have threads countcrbored at the bot- tom to ficiiitrte ninrUation. The bolt h- simil be keyed to prevent turning. (3) The circuit-cloring nut and bolt assembly ohai1 maintain the applied contuct pressure between the plated copper washer and the bus mcm
47、ben of the test- bypass block. (4) The insulating washer shall be made from dimen- sionally stable nontracking material and sha provide a minimum of 0.125 inch creep distance between bdt and bus sectiow. The bus sections shall be plated. (5)The wire stops shall extend to the center of Lhe terminal o
48、pening or beyond. (6)Rigid insulating bafflers shdl project at least 0.250 inch beyond any energized parts when the maxi- mum wire size U installed. (7)“he termin+ shall be aluminum bodied. me opening shall extend through the terminai body and, if the wire hole is round, shall be chamfered as neessary to facilitate installation of the largest size wire. (8)The terminal screws may be of the Allen type: 0.187 inch across flats for 100 A. 0.512 inch acres flats for 200 A. Figure 4 - 200 ampere Zest-block line-load, alternate construction sequence of connections 7 Copyright Nati
