While a NEMA 12 enclosure does provide more protection than a NEMA 1, a NEMA 12 is not the highest grade of protection available (despite its high numeric rating). Other ratings, like NEMA 4X and NEMA 6P, provide much more substantial protection from dust and liquid ingress.
The National Electrical Manufacturers Association (NEMA) defines standards used in North America for various grades of electrical enclosures typically used in industrial applications. Each is rated to protect against personal access to hazardous parts, and additional type-dependent designated environmental conditions.
Type 4: Weather tight (weatherproof) enclosures. Constructed for either indoor or outdoor use to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water. Will be undamaged by the external formation of ice on the enclosure.
The Difference between NEMA 4 and NEMA 4X Enclosures is that NEMA 4X Enclosures offer corrosion resistance. X (as 4X) indicates additional corrosion resistance.
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
Keeps out rain, snow and sleet, and also offers the protections of a NEMA 1 enclosure. Protects against damage from ice forming on the enclosure's exterior. Some NEMA 3 ratings offer protection against windblown dust, dirt and debris.
What does NEMA 1 mean? NEMA 1 is the most basic level of NEMA-rated protection. A NEMA 1-rated enclosure is rated to protect against small amounts of falling dirt, as well as accidental contact by employees or tools with live components inside the enclosure.
NEMA Ratings and IP Equivalency Chart
| NEMA Rating | IP Equivalent | Protection Against Solids |
|---|
| 4 | IP66 | 6 = Totally protected against dust |
| 4X | IP66 | 6 = Totally protected against dust |
| 5 | IP52 | 5 = Protected against dust - Limited ingress (no harmful deposit) |
| 6 | IP67 | 6 = Totally protected against dust |
NEMA 4 is watertight and dust-tight for inside and outdoor applications. NEMA 4X is everything listed, plus corrosion-resistant.
IP ratings cover protection only against the ingress of water and solid objects while NEMA includes supplementary protection standards against corrosion resistance and atmospheric gasses (such as acetylene or gasoline). There is no direct conversion between NEMA and IP ratings.
NEMA 7 enclosures are designed to contain an internal explosion without causing an external hazard. These enclosures are intended for indoor use in hazardous locations classified as Class I, Division I, Groups A,B,C, or D.
NEMA-4X – Gasketed door enclosure intended for indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, and hose directed water; undamaged by ice which forms on the enclosure. This is the most common enclosure in “food†environments.
According to NEMA's official standards, NEMA 3R enclosures are designed for both indoor and outdoor use and offer a degree of protection against the following: Hazardous Parts.
Protected from water spray less than 60 degrees from vertical. IP54. Protected from limited dust ingress. Protected from water spray from any direction. IP55.
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
NEMA 9 enclosures are designed to prevent the ignition of combustible dust. The enclosures prevent dust from entering and prevent enclosed heat generating devices from causing external surfaces to reach temperatures capable of igniting dust on the enclosure or igniting dust in the air surrounding the enclosure.
the National Electrical Manufacturers Association
The NEMA mark is a trademark of the National Electrical Manufacturers Association for its trade association services and publications, and it is used solely in connection with designating the National Electrical Manufacturers Association as the source of collateral for those goods and services, it isn't a certification
A NEMA 6-15 plug has two horizontally-aligned straight-blade prongs and one horseshoe-shaped prong. A 6-15 plug's prong shape and spacing only fits into a NEMA 6-15 receptacle. The horseshoe-shaped prong pushes into the receptacle's ground terminal and the 6-15's horizontal prongs slide into the receptacle's hot slots.
Many window-mount air conditioners, air compressors and residential welders plug into a Nema 6-30R. A Nema 6-30R connects to a 240-volt 30-amp electrical circuit with 10-gauge, or larger, three-strand wire. A Nema 6-30R has two straight, horizontally aligned prongs above its ground prong.
Standard industrial motors having a rating of IP55, normally considered 'weatherproof', are suitable for dry areas. The term 'IP55' is worth explaining. In simplified terms, the first number '5' means 'protection against dust', and the second number '5' means 'protection against water'.
In the case of a NEMA 5-15, the amperage rating is 15 amps. The amperage rating, like the voltage rating, is the highest amperage allowed for use with the device by the standard. Thus, an L5-15P is a locking 125 volt, 15 amp, plug. A 5-20R is a straight blade, 125 volt, 20 amp, receptacle or outlet.
The NEMA 14 devices are four-wire grounding devices (hot-hot-neutral-ground) available in ratings from 15 to 60 A. The voltage rating is 250 V. The 14-50 has a rating of 50 A, and a straight neutral blade sized so that it does not mate with 14-30 connectors.
