Class II Wiring Methods
Continuing Education Units (CEU): 0.10
Expected Duration: 1 Hour
This self-paced online course covers the particular problems of Class II areas, such as areas with an ignitable quantity of combustible dust. Wiring and protection methods used in Class II areas must be chosen to keep the electrical equipment and wiring from providing an ignition source for the combustible dust.
Upon completion you should be able to:
- Describe the primary protection method for Class II areas
- List and describe wiring methods permitted in Class II, Division 1 areas
- List and describe flexible wiring methods that are permitted
- Describe how conduit and cable seals are used in Class II, compared to Class I
- List and explain two methods of creating dust-ignitionproof enclosures
- Understand how wiring is handled when Class I and Class II hazards are present at the same time and in the same area
- Understand how the definition of "limited energy circuit" varies in different contexts
- Understand how the characteristics and hazards of metal dusts compare to other types of dust
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
- Class II areas are areas classified due to the presence of ignitible quantities of combustible dust.
- Wiring and protection methods used in Class II areas must be chosen to keep the electrical equipment and wiring from providing an ignition source for the combustible dust.
- Â Wiring methods must be selected to isolate ignition sources from combustible dusts and to be compatible with dust-ignitionproof enclosures. In Class II, Division 2 areas, most enclosures are not required to be dust-ignitionproof. However, any enclosures that are not required to be dust-ignitionproof must be dusttight in both Division 1 and Division 2 areas.
- Seals are not required to be explosionproof and are only required where dust could enter a dust-ignitionproof enclosure through a raceway.
- In order to use ordinary wiring methods in Class II areas, the energy in the circuits must be limited to levels that cannot ignite the specific dusts present.