This document supersedes IEEE Std 28-1972 (ANSI C62.1-1971) and revises many portions ofthe previous edition. Three new significant design tests have been added to determine:(1) The highest 1.2 x 50 standard impulse which the surge arrester will allow without sparkover(2) The effect of external contamination on sparkover(3) Surge arrester disconnector characteristics. Additional substantive change...