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This paper reviews progress in arc flash standards and requirements and the protective relaying techniques used to reduce arc flash energy, primarily through “high-speed detection and operation”. In some cases, the high-speed zone is permanent, and in others it is switched in during maintenance or repair. The need for high-speed “backup” arc flash protection will be discussed. Using a single high-speed zone of protection, thus establishing the level of “personal protective clothing,” begs the question “what if the single high-speed zone fails”? Several arc flash clearing time examples will demonstrate this concern.