UL 674

Electric Motors and Generators for Use in Hazardous (Classified) Locations

1.1 This standard applies to electric motors and generators or submersible and nonsubmersible sewage pumps and systems suitable for use in Class I, Division 1, Groups B, C and D, and Class II, Division 1, Groups E, F and G, hazardous (classified) locations as defined by the Canadian Electrical Code, C22.1 Part I (CEC), the National Electrical Code, ANSI/NFPA 70 (NEC), and NOM-001 - SEDE.

1.2 This standard covers the same type of electrical equipment indicated in 1.1 for installation and use in Class I, Zone 1, Groups IIA and IIB, IIB+H2, and Zone 20 and 21 hazardous locations.

1.3 This standard also covers other rotating machinery such as, but not limited to, electric brakes, tachometers, encoders, and slip rings.

1.4 This standard does not address types of protection other than explosion-proof or dust-ignition-proof.

1.5 For Canada Only - This standard does not include Canadian energy efficiency or product performance requirements. For such requirements, see Annex a, item 19. It is possible that item 19 is referenced in whole or in part in federal, provincial, territorial, or local laws or regulations relating to energy efficiency or product performance. The appropriate governmental authorities should be consulted to confirm whether item 19 has been referenced in laws or regulations.

Note: This standard also does not include U.S. energy efficiency requirements for electric motors used in hazardous (classified) locations.


  • Edition Number: 5
  • Edition Date: 05/31/2011
  • Price Code: B
  • Type: ulcsance
  • ANSI Approved: 11/06/2015
  • DOD Approved: 11/06/1987