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Types of Enclosures (NEMA Ratings)

The National Electrical Manufacturers Association (NEMA) Standard 250 defines many different types of enclosures to be used in various control applications. Of these types, BFS designs most control panels using Type 1, Type 12, or Type 4 enclosures.

Since most boiler room equipment is installed indoors in a relatively dry environment, a Type 1 enclosure is a good choice in these instances. Such an enclosure provides physical protection of the internal components and keeps personnel from inadvertently touching high-voltage components. As long as there are no oil or water leaks near a control panel, the Type 1 enclosure is a cost-effective solution.

The main drawback of a Type 1 enclosure is that it is not sealed from the outside air. This allows dust or other particles to enter and deposit on the internal components. A Type 12 enclosure prevents this by maintaining a dust-tight seal around the door, provided it is secured properly. This seal also protects against dripping and light splashing of liquids.

When an enclosure is subjected to liquids under greater pressure, such as splashing and hose-directed water, a Type 4 enclosure is used. It also provides protection against rain, snow, sleet, and ice. Therefore, it is a good industrial choice for any equipment to be installed outdoors.

For more information on types of enclosures, read NEMA Standard 250-2003, Enclosures for Electrical Equipment.