This self-paced online course covers wiring methods and equipment that can be used in Class III areas. These areas are classified due to the presence of fibers or flyings.

Upon completion you should be able to:

• Understand the hazards and concerns specific combustible fibers and flyings
• Explain why stringent housekeeping requirements are important in Class III areas
• Understand why surface temperature is a concern in Class III areas
• Understand how the situation is handled when Class II and Class III hazards are present at the same time and in the same area
• List and describe wiring methods that are permitted in Class III areas
• List the two essential characteristics for equipment to be permitted in Class III areas

Who Will Benefit

Anyone whose job involves designing, reviewing, evaluating or installing fire protection systems, including: designers, installers, engineers, electrical contractors, technicians, project managers, fire marshals, and architects.

Course Summary

• Ignitible fibers and flyings that may be ignited by electrical equipment and wiring must be isolated from the electrical ignition sources.
• Equipment is required to be dusttight generally, but surface temperatures must be controlled so that fibers or flyings are not ignited by contact with surfaces, including surfaces where fibers or flyings may collect.
• Some equipment is required to be identified for Class III areas, but most equipment must simply be dusttight. It must also be marked with a maximum surface temperature if the equipment produces heat.
• The maximum surface temperatures are quite low compared to most equipment used in Class I or Class II areas. Lower temperatures are required where equipment is subject to overloading.
• The wiring methods that may be used include those that are suitable for Class I or Class II areas but a few additional wiring methods are permitted, such as rigid nonmetallic conduit (RNC).
• Class II equipment may be used in Class III areas because it is dusttight, but surface temperatures must be limited to sufficiently low values.