NEMA Enclosure Types

NEMA Enclosure Types

The purpose of this document is to provide general information on the definitions of
NEMA Enclosure Types to architects, engineers, installers, inspectors and other
interested parties. [For more detailed and complete information, NEMA Standards
Publication 250-2003, “Enclosures for Electrical Equipment (1000 Volts Maximum)”
should be consulted. This Standards Publication as well as all other NEMA publications
are available from IHS @ 800 854-7179 or http://www.global.ihs.com]
Definitions
[from NEMA 250-2003]
In Non-Hazardous Locations, the specific enclosure Types, their applications, and the
environmental conditions they are designed to protect against, when completely and
properly installed, are as follows:
Type 1 Enclosures constructed for indoor use to provide a degree of protection to
personnel against access to hazardous parts and to provide a degree of protection of
the equipment inside the enclosure against ingress of solid foreign objects (falling dirt).
Type 2 Enclosures constructed for indoor use to provide a degree of protection to
personnel against access to hazardous parts; to provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt); and
to provide a degree of protection with respect to harmful effects on the equipment due
to the ingress of water (dripping and light splashing).
Type 3 Enclosures constructed for either indoor or outdoor use to provide a degree
of protection to personnel against access to hazardous parts; to provide a degree of
protection of the equipment inside the enclosure against ingress of solid foreign objects
(falling dirt and windblown dust); to provide a degree of protection with respect to
harmful effects on the equipment due to the ingress of water (rain, sleet, snow); and that
will be undamaged by the external formation of ice on the enclosure.
Type 3R Enclosures constructed for either indoor or outdoor use to provide a degree
of protection to personnel against access to hazardous parts; to provide a degree of
protection of the equipment inside the enclosure against ingress of solid foreign objects
(falling dirt); to provide a degree of protection with respect to harmful effects on the
equipment due to the ingress of water (rain, sleet, snow); and that will be undamaged
by the external formation of ice on the enclosure.
National Electrical Manufacturers Association Approved by NEMA Enclosures Section
1300 N. 17th Street, Suite 1752 Nov 2005
Rosslyn, VA 22209 Page 1 of 2