New NEMA 250, Electrical Enclosures

NEMA 250, “Enclosures for Electrical Equipment (1000 Volts Maximum),” has just been updated and the new 2015 Edition is available from Document Center Inc. now.  This new update replaces the previous 2008 edition (now obsolete).  It covers the topic of cabinets for electrical equipment, ones that are commonly used for providing protection from the elements and to equipment users, and from access by unauthorized personnel.

The NEMA 250 is widely used not only by manufacturers, but by enclosure purchasers to determine what enclosure suits their purposes best.  It also provides information on features expected from an electrical enclosures.  And it defines the tests used to confirm that a given enclosure meets various environmental requirements.

The standard covers enclosures used for both hazardous (called classified) and non-hazardous (termed unclassified) locations.  Unclassified locations are covered in the main body of the standard and classified are in Annex A.

NEMA 250 starts with the usual scope, references, and definition clauses.  Then it reviews the types, features and applications for these electronic enclosures.  You’ll also find specific requirements for both construction and marking.  And there are a number of tests for these products:  rain, dust, salt spray, corrosion, and so on.

Who should be using this document?  It’s primarily addressed to enclosure manufacturers since it provides performance requirements for various classes of electrical enclosures.  In additional, this provides electrical enclosure purchasers with the tools to assess and compare the many types of enclosures available on the market today.

Need a copy?  Head to the Document Center webstore at and order it now!  Or contact our staff by phone (650-591-7600), fax (650-591-7617) or email (  We’ve been providing our customers with NEMA standards since the 1980’s.  Make us your standards experts.

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Claudia Bach

Claudia Bach is the President of Document Center Inc. and a world-wide recognized expert on Standards and Standards Distribution. You can connect with her on Google+

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