ANSI C78.20-2022

This standard sets forth physical and electrical characteristics of the group of incandescent lamps that have A, G, PS, and similar bulb shapes with E26 single- and double-contact medium screw bases including the reduced wattage versions. Only clear, inside frost, frost-equivalent, and white bulb finishes are acknowledged. Excluded from this standard are tungsten-halogen and projection lamps.
Other groups of incandescent lamps are covered in the following associated standards:
ANSI C78.21 American National Standard for Incandescent Lamps—PAR and R Shapes
ANSI C78.22 American National Standard for Incandescent Lamps—A, G, PS, and Similar Shapes with E39 Mogul Screw Bases
ANSI C78.23 American National Standard for Specification for Incandescent Lamps—Miscellaneous Types
Many of the lamps covered by this standard do not relate to internationally standardized lamps that appear in International Electrotechnical Commission (IEC) standards. The subject lamps are not limited with regard to design life as are those in IEC 60064 Tungsten Filament Lamps for Domestic and Similar General Lighting Purposes. Their physical size may or may not comply with similarly rated IEC types.