The National Electrical Manufacturers Association (NEMA) announced that ANSI Accredited Standards Committee C84 revised ANSI C84.1 American National Standard for Electric Power Systems and Equipment—Voltage Ratings (60Hz). This standard establishes nominal voltage ratings and operating tolerances for 60Hz electric power systems above 100V.
ANSI C84.1 establishes standards voltage ranges for systems so products can be designed to provide operation in those systems. It also includes preferred voltage ratings up to 1200kV maximum system voltage.
With the 2016 revision of ANSI C84.1, a 690/400V category has been added to the Low Voltage Class in table 1, and a paragraph discussing conservation voltage reduction has been added to Annex B.
ANSI C84.1-2016 can be purchased in hard copy or electronic download on the NEMA website.