ANSI C12.10-2004 pdf download American National Standard for Physical Aspects of Watthour Meters- Safety Standard
1 Scope
This standard covers the physical aspects of both detachable and bottom-connected watthour meters and associated registers. These include ratings, internalwiring arrangements, pertinent dimensions, markings, and other general specifications. Refer to the latest version of ANSI C1 2.1 and ANSI C1 2.20 for performance req uirements.
2 References
The following publicationshall be used in conjunction with this standard. Use the latest published version of the document if no year is specified:
ANSf C1 2.1 , American National Standard for Electric Meters
ANSI MH1 0.8.1 – 2000, Linear Bar Code and Two Dimensional Symbols Used in Shipping, Receiving, and Tran sport Ap pl ication s
The Handbook for Electricity Metering, 1 Oth edition 2002,The Edison Electric Institute
3 Standards applicable to watthour meters
3.1 Mounting
Mounting arrangementshall be either detachable (socket or type “S”) or bottom-connected (type “A”).
3.2 Voltage and frequency
The typical voltage and frequency ratings are 1 20,240,277 , or 480 V and 60 Hz.
3.3 Gurrent classes and test amperes (TA)
The normal current classes and test amperes shall be as listed in Table 1 :
NOTE-Current classes 200 and 320 in “S” type only.
Other values of test amperes may be used.
3.5 Rotor (electromechanical meters only) (see Figure 2)
3-5.1 Direction of rotation
Viewed from the top, the direction of the rotor’s rotation shall be counter clockwise.
3.5.2 Provisions for testing
Meters shall provide the following means for testing:
3.5.2.1 Radialmarkings
Two rings of radial markings shall be placed on the top outer surface of the rotor disk. The outer ring shall have 1 00 equally spaced marks, and the inner ring shall have 1 80 equally spaced marks.
3.5.2.2 Index markings
Index markings shall be provided on the rotor disk.
3.5.2.3 Holes
1 ) For single-stator watthour meters, two holes 1 80o apart and equidistant from the center of the rotor disk shall be provided.
2) For multi-stator meters, one or two holes shall be provided. When two holes are used, they shall be as described in subclause 3.5.2.3(1 ).
3.6 Galibration adjustments(electromechanical metersonly)
3.6.1 Means required for making calibration adjustmentshall be readily accessible.
3.6.2 The direction of control of light load and full load adjustmentshall be marked with “F” for fast and “S” for slow.
3.6.3 All calibration adjustmentshall be loaded to prevent change in meter adjustment during normal handling or vibration.
3.7 Meter nameplate
The nameplate shall contain the following information:
1 . Form designation(s) or circuit description
2. Watthour meter or other description
3. Manufacturer’s name or trademark
4. Manufacturer’serial number
5. Manufacture/s type
6. Current class
7. Rated voltage
8. Number of wires
9. Frequency
1 0. Test amperes
1 1 . Watthour meter constant
1 2. Watthour meter test constant (where applicable)
Transformer rated meters shall contain space for the following additional information:
1 ) Multiply By
2) Current transformeratio (e.9., 200:5)
3) Voltage transformeratio (e.9., 20:1 )