THE DIFFERENCE BETWEEN A NEMA 3 RATED ENCLOSURE AND A NEMA 4 RATED ENCLOSURE
Published on: August 12, 2021 by Blair Haas
One of the most frequent questions we are asked is to clarify the NEMA rating system for enclosures. There are many misconceptions about the ratings including that a higher number rating means a greater level of protection or that all ratings suggest that the products are waterproof or dustproof. For today’s blog, I am going to focus on two of the outdoor ratings and describe what they mean, how they are tested and what the difference are. These are the NEMA 3 and NEMA 4 ratings which are often confused but mean very different levels of protection.
THE N3R Enclosure series provide excellent NEMA 3r outdoor protect
NEMA 3 RATINGS TESTING EXPLAINED
Generally, NEMA 3 means the enclosure is weather-resistant. It protects the components against falling dirt and windblown dust, against weather hazards such as rain, sleet and snow, and is undamaged by the formation of ice. It also provides the same protection as a NEMA 1 enclosure which means that the interior cannot be accessed from the exterior with fingers or other similar objects. There are several tests that are performed to certify the ratings.
- A rod of a specific size is used to insure that it cannot penetrate to the interior of the box.
- A water spray of about 5 psi is used on the top and the sides of the box to simulate rain or sleet with a 5 mph wind. The interior must remain dry
- There is an icing test to insure that ice neither penetrates the box and that formation of ice does not impede the use of the box.
- Dust tests are also performed.
- Also note that these products are meant for use outdoors so the materials must offer the appropriate UV protection.
BUT THERE ARE ALSO NEMA 3 SUBGROUPS INCLUDING NEMA 3R, NEMA 3S, NEMA 3X, NEMA 3RX AND NEMA 3SX
Just when you thought you understood NEMA 3, they toss in some variables. NEMA 3R means that the product does not have to meet the dust standards and so has not passed the dust test. It may not have a dust gasket included although this may be required to avoid the ingress of rain. NEMA 3S means that the product can operate even when the box is “laden with ice”. The test for this is typically performed on a finished product, not on the enclosure alone. The addition of the suffix “x” means that the product has corrosion protection. A 3x rated enclosure would be used near salt water, for example.
The PN Series is a plastic NEMA 4X rated enclosure
NEMA 4 ENCLOSURES HAVE DIFFERENT REQUIREMENTS THAN NEMA 3 ENCLOSURES
NEMA 4 enclosures are also required to be weather resistant but have more stringent requirements compared to a NEMA 3 Enclosure. It is also able to be used outdoors thus materials must be able to withstand the outdoor UV levels without degrading. The testing for NEMA 4 consists of spraying the enclosure with at least 65 GPM of water from a 1 inch nozzle hose from a distance of not less than 10 feet for 5 minutes. No water can penetrate the box. There is one subgroup in the NEMA 4 rating system which is NEMA 4x. This is the same as on the NEMA 3x ratings and means that it can withstand corrosion.
WHAT IS THE MAJOR DIFFERENCES BETWEEN NEMA 3 AND NEMA 4 ENCLOSURE RATINGS?
A NEMA 4 rated enclosure generally provides a higher level of protection than does a NEMA 3 enclosure. As we noted, the spray test for the NEMA 4 enclosure is much more stringent and suggests different types of applications. A NEMA 4 enclosure can be used in applications located outdoors where weather is a factor, but also when the product may need to be hosed down. A good example of this would be in the food industry, medical industry, and other situations where extensive cleaning would be required. A NEMA 3 box is used in more moderate locations such as in construction, transportation, or even on docks. The one advantage of a NEMA 3 box is that it is tested to withstand the formation of ice which a NEMA 4 box might do but is not so required.
WHAT IF YOU HAVE MORE QUESTIONS?
Check out our NEMA/IP Rating Guide.
Bud offers a wide range of NEMA 3 and 4 rated enclosures and has a strong technical staff to help you insure that you select the best possible enclosure to meet both your protection and price objectives. Bud also can modify its enclosures to make sure that you can readily prepare for the installation of your components without compromising your desired ratings. Reach out to us through your favorite Bud distributor or directly at 440-946-3200, via chat at www.budind.com, or email at saleswest@budind.com.
FAQs
A NEMA 4 rating is the same as a NEMA 3 rating, but it adds protection against hose directed water. The testing for NEMA 4 consists of spraying the enclosure with water at 65 gallons per minute from a 1-inch hose. This is a lot more water than in the NEMA 3 test, which is a water spray at 5 psi.
Is NEMA 4X better than 3R? ›
The main difference is that the Type 4X provides superior protection for the component inside. A Type 3R enclosure provides general protection for the electrical devices it contains.
Is NEMA 4 dust proof? ›
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.
Is NEMA 4X enclosure an explosion proof? ›
Unfortunately, NEMA 4X isn't Ex-Proof, though it is resistant to some environments. Similarly, NEMA 12 is similar to NEMA 4X; however, it is resistant to circulating dust and other weather patterns and less so to the water.
What is the NEMA protection rating? ›
The NEMA rating system is defined by the National Electrical Manufacturers Association, and frequently signifies a fixed enclosure's ability to withstand certain environmental conditions. NEMA 1 Indoor use primarily to provide a degree of protection against limited amounts of falling dirt.
Is NEMA 4 good for outdoor? ›
NEMA 4 enclosures are intended mainly for outdoor use where extra protection against moisture and wind-driven rain is required.
Is NEMA 3R good for outdoor use? ›
NEMA 3R Electrical Enclosures
Our adherence to UL 508A standards will give you a quality weatherproof enclosure resistant to rain, ice, and snow. NEMA 3R electrical enclosures are compatible with both indoor and outdoor applications and hold the least demanding rating for outdoor use.
Does NEMA 4 have to be stainless steel? ›
There are a variety of options when it comes to materials, like polycarbonate, aluminum and stainless steel. You can explore material choices for NEMA 4X enclosures on our blog post “Which NEMA 4X Enclosure Type Is Right for You?”
Is NEMA 4 gasketed? ›
NEMA 4 enclosures are gasketed and the door is clamped for maximum sealing. NEMA 4 enclosures are used in many applications where an occasional washdown occurs or where machine tool cutter coolant is used. They also serve in applications where a pressurized stream of water will be used.
What IP rating is explosion proof? ›
The minimum requirement for Explosion-Proof protection is IP54.
More specifically, both ratings provide an excellent level of protection against adverse weather conditions, repeated hose washdowns and airborne particulates such as windblown dust. However, a NEMA 4X enclosure has an additional feature that a NEMA 4 enclosure lacks: protection from corrosion.
What material is NEMA 4X made of? ›
NEMA 4X enclosures are generally manufactured using made of 304 & 316 stainless steel because of it's high degree of protection from corrosive materials.
What is the difference between NEMA 3 and 4? ›
A NEMA 4 rating is the same as a NEMA 3 rating, but it adds protection against hose directed water. The testing for NEMA 4 consists of spraying the enclosure with water at 65 gallons per minute from a 1-inch hose. This is a lot more water than in the NEMA 3 test, which is a water spray at 5 psi.
What is NEMA 4 protection? ›
NEMA-4 – Gasketed door enclosure intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; undamaged by ice which forms on the enclosure.
What is NEMA 4X degree of protection? ›
NEMA 4X enclosures also provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, hose-directed water, and corrosion.
What is NEMA 3R for? ›
NEMA 3R Enclosures
Designed for outdoor use, offering protection against rain and sleet. Commonly used for housing power distribution, lighting contactors, switchgear, and other electrical components in applications such as exterior electrical panels on buildings.
Is NEMA 4X better than NEMA 6? ›
NEMA Type 6 and 6P Enclosures
The 6 and 6P ratings offer all of the same weatherproofing features of a 4 or 4X enclosure, but add protection against: Occasional temporary submersion (Type 6)
What is the equivalent of NEMA 4X? ›
NEMA Enclosure Ratings & IP Equivalents
| NEMA Rating | IP Equivalent | IP Definition |
|---|
| 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. |
| 6P | IP67 | 6 = Totally protected against dust. |
8 more rowsWe recommend electrical enclosures meet or exceed a NEMA rating of Type 4 or Type 4X for use in a Class1 Div2 hazardous location when used with appropriate purge systems.
