The National Electrical Manufacturers Association (NEMA) has published ANSI C12.20-2010 American National Standard for Electricity Meters—0.2 and 0.5 Accuracy Classes. The standard, last published in 2002, was produced by the ANSI C12 Accredited Standards Committee for Electricity Metering, Subcommittee 16.

ANSI C12.20 establishes acceptable performance criteria for electricity meters, and covers accuracy class designations, current class designations, voltage and frequency ratings, test current values, service connection arrangements, pertinent dimensions, form designations, and environmental tests.

In this revision, the standard was broadened to allow three phase current and voltage sources as an optional test method to the existing single phase, series, parallel method.

The contents and scope of ANSI C12.20 may be viewed, or a hardcopy or electronic copy purchased for $67, by visiting www.nema.org/stds/c12-20.cfm, or by contacting IHS at 800-854-7179 (within the U.S.), 303-397-7956 (international), 303-397-2740 (fax), or www.global.ihs.com.

NEMA is the association of electrical and medical imaging equipment manufacturers. Founded in 1926 and headquartered near Washington, D.C., its approximately 450 member companies manufacture products used in the generation, transmission and distribution, control, and end use of electricity. These products are used in utility, industrial, commercial, institutional, and residential applications. The association’s Medical Imaging & Technology Alliance (MITA) Division represents manufacturers of cutting-edge medical diagnostic imaging equipment including MRI, CT, x-ray, and ultrasound products. Worldwide sales of NEMA-scope products exceed $120 billion. In addition to its headquarters in Rosslyn, Virginia, NEMA also has offices in Beijing and Mexico City.