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ANSI/NEMA C29.4-2022
Wet Process Porcelain Insulators -Strain Type
Specifications including ratings, tests, and dimensions for interchangeability for apparatus and line insulators of all types, except those on communication lines. Also, within the scope is a directive to bring the C29 series of standards in harmony with their counterparts in the IEC insulator standards wherever practical.
NEMA: National Electrical Manufacturers Association [nema]