What is Article 500 of the NEC?
Dust particles that are 500 microns or smaller and present a fire or explosion hazard when dispersed and ignited in air.
What are the 4 groups of the NEC?
Under the NEC system used in the United States the groups are:
- Group A – Acetylene.
- Group B – Hydrogen.
- Group C – Ethylene.
- Group D – Propane.
- Group E – Metal dusts (eg. Magnesium, Aluminum, Titanium etc.)
- Group F – Carbon-based (eg. coal and charcoal)
- Group G – Nonconductive dusts (eg. Flour, wood/sawdust, plastic dust)
What is a Class II dust?
A Class II, Division 1 location is a location. (1) In which combustible dust is in the air under normal operating conditions in quantities sufficient to produce explosive or. ignitible mixtures, or. (2) Where mechanical failure or abnormal operation of machinery or equipment might cause such explosive or ignitible.
What is temperature code T3C?
T3B and T3C correspond to 165°C and 160°C maximum respectively and will always require winding thermostats.
What NEC chapter covers hazardous locations?
NEC Article 502: Class II Hazardous Locations.
What is Group D gas?
Group D—Atmospheres containing a flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor whose MESG is greater than 0.75 mm or MIC ration is greater than 0.80. Typical gases include acetone, ammonia, benzene, butane, ethanol, gasoline, methane, natural gas, naphtha, and propane.
What are the NEC group classifications and the materials involved?
NEC & CEC Groups Groups define the type of hazardous material in the area. Groups are broken out into seven different segments – A through G. The NEC lists and defines hazardous gases, vapors and dusts by Groups characterized by their combustible or ignitable properties.
What is classification temperature?
What is Temperature Classification. Temperature classification (also known as temperature class, or T class) defines the maximum surface temperature that a product destined for use in a potentially hazardous atmosphere is allowed to operate at, relative to an ambient temperature of -20°C to +40°C.