This standard covers the physical aspects of both detachable and bottom-connected watthour meters and associated registers. These include ratings, internal wiring arrangements, pertinent dimensions, markings, and other general specifications. Performance requirements are included in ANSI C12.1 and ANSI C12.20.

Changes were made to the standard to bring it up to date with modern practice and new editions of other ANSI C12 standards. These changes include updating the title to more accurately reflect the contents, moving performance specifications for solid state registers on electromechanical meters to ANSI C12.1, and the addition of new form designations.