UL 877-1993
用于危险(分类)场所的安全断路器和断路器外壳的 UL 标准(第四版;1999年11月18日(含)的修订重印)
UL Standard for Safety Circuit Breakers and Circuit-Breaker Enclosures for Use in Hazardous (Classified) Locations (Fourth Edition; Reprint with Revisions Through and Including November 18@ 1999)