UL Standards & Engagement Standard for Explosive Atmospheres - Part 25: Intrinsically Safe Electrical Systems UL 60079-25

This part of IEC 60079 standard contains the specific requirements for construction and assessment of intrinsically safe electrical systems, type of protection "i", intended for use, as a whole or in part, in Class I, Zone 0, 1, or 2, or Zone 20, 21, or 22 hazardous (classified) locations as defined by the National Electrical Code® (NEC), ANSI/NFPA 70® in locations in which the use of Group I, II or III apparatus is required . NOTE 1 This standard is intended for use by the designer of the system who may be a manufacturer, a specialist consultant or a member of the end-user's staff. This standard supplements and modifies the general requirements of ANSI/ISA-60079-0 and ANSI/ISA-61241-0 IEC 60079-0 and the intrinsic safety standard ANSI/ISA-60079-11 and ANSI/ISA-61241-11 IEC 60079-11 . Where a requirement of this standard conflicts with a requirement of ANSI/ISA-60079-0, ANSI/ISA-60079-11, ANSI/ISA-61241-0 IEC 60079-0 or ANSI/ISA-61241-11 IEC 60079-11 , the requirement of this standard takes precedence. This standard supplements IEC 60079-11, the requirements of which apply to electrical apparatus used in intrinsically safe electrical systems. The installation requirements of Group II or Group III systems designed in accordance with this standard are specified in the National Electrical Code ANSI/NFPA 70 IEC 60079-14 . NOTE 2 Group I installation requirements are presently not provided in IEC 60079-14.