The meaning of interrupting ratings on low voltage protective equipment

Questions sometimes arise about the meaning of information on the nameplate of a piece of low voltage protective equipment. One item, the interrupting rating, may be somewhat difficult to understand. Various standards dictate how equipment is to be tested in order to receive a certain interrupting rating. The meaning of the actual nameplate interrupting rating may differ slightly depending on the test performance required by the appropriate testing standard. This paper reviews the various test standards for current-limiting fuses, low-voltage power circuit breakers, and molded-case circuit breakers. Comments are made regarding the nameplate interrupting rating and the actual tested performance