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#85216 - 06/09/03 12:26 AM NEMA type 7 enclosure
Nagelec Offline

Registered: 06/08/03
Posts: 12
Loc: Sharjah, UAE
Is NEMA Type 7 enclosures are for indoor use only? Can any one please clarify this and give the NEC reference?

2014 / 2011 NEC & Related Books and Study Guides
#85217 - 06/13/03 10:35 AM Re: NEMA type 7 enclosure
Philip White Offline

Registered: 08/06/02
Posts: 13
Loc: trenton, tennessee, usa
then term "nema" is from the national electrical manufacturers association - a US manufacturere organization. nema standards describe each type of enclosure in general and functional terms, and specifically omits reference to construction details.

NEMA 7 is defined as a hazardous location type of enclosure.

NEMA 7 - enclosures are for use indoors in locations classified as Class 1, Groups A,B,C, or D, as defined in the NEC. Nema standard 1-10-1979.

this is from the Weigmann enclosure catalog dated 1996. other enclosure brands should also have this listing in their catalogs if you have one handy.

hope this helps.

#85218 - 06/13/03 09:52 PM Re: NEMA type 7 enclosure
Nagelec Offline

Registered: 06/08/03
Posts: 12
Loc: Sharjah, UAE
Hi Philip,

Thanks for your reply. I found in ANSI/API RP 14F-91, table 4.11 the description of various NEMA enclosures available, which says,

" An explosion proof enclosure (NEMA type 7) is desgined to meet the application requirements in art 500 of NEC for Class I locations and is designed in accordance with the latest specifications of UL for particular groups of gases. Certain NEMA 7 enclosures are approved for sdeveral groups (such as group B,C and D), while others may be approved only for a particular group (such as group D). NEMA 7 enclosures are not necessarily suitable for outdoor use".

As I understood, NEMA 7 denotes to only "explosion" type and not to any Ingress protection of enclosures.

#85219 - 06/24/03 07:17 PM Re: NEMA type 7 enclosure
John Steinke Offline

Registered: 04/03/01
Posts: 509
Loc: Reno,Nv., USA
The enclosure will often have multiple NEMA classifications, detailing all the areas where it is intended for use. For example, it may be marked both NEMA 4 (hose tight) and NEMA 12 (oil tight.) An outdoor hazardous location requires either an enclosure that is rated for both hazardous and wet locations, or it may be placed under an overhang to remove it from the "wet" location.
Where locations or NEMA designations are absent, and indoor, dry location is assumed.


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