ANSI C12 Standards for Electricity Metering
Standards for metering in the United States are developed under the auspices of the American National Standards Institute, Inc. with the National Electrical Manufacturer's Association serving as secretariat. ANSI standards are voluntary standards. That means that unlike most other coutries where national standards carry the requirement of law, in the US complying with the standards is voluntary unless mandated at the state or local level.
There are many sections to the ANSI C12 standard, each covering specific aspects of metering. These standards are developed by a consensus process. The working committees for standard development generally meet twice a year. Each standard is reviewed continuously with new revisions published every five years. The table below shows the current standards and new standards under development. if a standard designation is highlighted, you can get detailed information about current activity in the standard by double clicking on the link.
| Designation | Title | Status | Subcommittee |
| C12.1-2008 | Code for Electricity Metering | Final revision process, ballot expected 2013 | SC 1 |
| C12.4-1984 (R2011) | Mechanical Demand Registers | Reaffirmed, Published Jan 6, 2012 | SC 1 |
| C12.5-1978 (R2002) | Thermal Demand Registers | Reaffirmed, Published Oct 25, 2012 | SC 1 |
| C12.6-1987 (R2012) | Marking and Arrangement of Terminals for Phase-Shifting Devices Used in Metering | Reaffirmed, Published Sep 26, 2012 | SC 15 |
| C12.7-1993 (R2005) | Requirements for Watthour Meter Sockets | Significant revision approved April 2013. Ballot in process | SC 15 |
| C12.8-1981 (R2002) | Test Blocks and Cabinets for Installation of Self-Contained Watthour Meters | Published Dec 18, 2012 | SC 15 |
| C12.9-1993 (R2007) | Test Switches for Transformer-Rated Meters | Major additions, Approved April, 2013. Ballot in process | SC 15 |
| C12.10-2011 | Electromechanical Watthour Meters | Approved Jun 28, 2011, Published Oct 2011 | SC 1 |
| C12.11-2006 (R2007) | Instrument Transformers for Revenue Metering, 10kV BIL to 350 kV BIL | Revised/Reaffirmed 2013, Ballot in process | SC 15 |
| C12.18-1996 (R2006) | Protocol Specification for ANSI Type 2 Optical Port | BSR 11 Extension to 2013 | SC 17 WG4 |
| C12.19-2008 | Utility Industry End Device Data Tables | Revised/Reaffirmed 2013, Ballot in process | SC 17 WG2 |
| C12.20-2010 | For Electricity Meters - 0.2 and 0.5 Accuracy Classes | Approved Aug 31, 2010, Published Sep 2010 | SC 16 |
| C12.21-1999 (R2006) | Protocol Specification for Telephone Modem Communication | Revise/Reaffirm 2011 (BSR 11 Extension to 2013) | SC 17 WG4 |
| C12.22-2008 | Protocol Specification for Interfacing to Data Communication Networks | Revise/Reaffirm 2013, Ballot passed. In preparation for publishing | SC 17 WG1 |
| C12.23 | AMR Device Compliance Test Standards | MOU Signed - Work in Process | SC 17 WG3 |
| C12.24 TR-2011 | Definitions for Calculations of VA, VAh, VAR, and VARh for Polyphase Electricity Meters | Published as Technical Paper not Standard Oct 2011 | Closed |
| C12.26 (Placeholder) | Communication Interface Module | Inactive | Inactive |
| C12.27 (Placeholder) | Meter Upgradeability | Work in process | SC 27 |
| C12.29 (Placeholder) | Field Testing of Metering Sites | Work in process | SC 29 |
| C12.30 (Placeholder) | Test Requirements for: Metering Devices Equipped with Service Switches | Technical Report Ballotted Apr 2, 2013 | SC 1 |