The National Electrical Code (NEC) defines hazardous locations as those areas where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings. Electrical equipment and/or electrical components can sometimes be a source of ignition in these volatile areas. To protect against such ignition, enclosures are often used to house electrical equipment and/or electrical components located in volatile areas. These enclosures are often made of heavy cast metal and are bolted shut. Electrical equipment or components housed in an enclosure often require maintenance or must be replaced. When this occurs, an electrician or maintenance person is often exposed to the hazardous environment for extended periods of time. Further, the enclosure may be located in areas that are difficult to access and may be exposed to harsh climatic conditions.
USPTO Backgrounds
USPTO Backgrounds