With so many NEMA ratings and material types available, selecting the right electrical enclosure can be a daunting task. Making the wrong selection, be it with moisture, dust or challenging environments, can lead to expensive damages. This guide addresses these issues and aims to help you select the most appropriate solution for your requirements. So, let’s start!
1) What Are NEMA Ratings?
“NEMA is short for National Electrical Manufacturers Association. This organisation established a rating system to indicate how well an enclosure protects its contents from dust, water, corrosion, and even ice.”
In selecting an electrical enclosure, you must consider the level of internal protection required. In this regard, NEMA ratings are helpful.
Well, every NEMA Rating provides protective features for certain exposure variables. Some enclosures are specifically designed for dry indoor environments. Others can withstand exposure to rain, snow, or harsh chemicals. Generally, the higher the rating number, the better the protection.
These ratings matter whether your equipment is located indoors or outdoors. If you install an indoor-only box outside, water or dust may damage your system. This is the reason why selecting the appropriate rating aids you in avoiding expensive damage or safety concerns.
To make it clearer, if your setup will be subjected to water, then a watertight enclosure is a requirement. If it’s placed inside a factory with lots of dust particles, then it should be sealed against dirt. Certain enclosures are also designed to resist corrosion from chemicals and salt.
2) Common NEMA Ratings and What They Protect Against
Every NEMA rating indicates the degree to which an electrical enclosure safeguards its contents. This assists you in selecting the right enclosure box for the environment, which could be dry, wet, dusty, or even a chemical-filled one. Here is a summary of popular NEMA ratings from 1 to 13.
NEMA 1: For indoor purposes. It protects against accidental contact with live wires or internal parts. No guard against dust, water or oil. Best suited for clean and dry environments such as office buildings and electrical closets.
NEMA 2: Suitable for indoor use only. Offers protection from light dripping water and condensation-like moisture. Works well in laundry rooms and storage areas where light moisture is present.
NEMA 3: Intended for use outdoors. Protects from falling rain, snow, sleet, and windblown dust. Also, protects against damage caused by ice forming on the enclosure. Used in light outdoor conditions.
NEMA 3R: Also for outdoor use. Enclosure NEMA 3r protects against rain and ice but not dust. Commonly found in utility boxes and lighting panels placed in open environments.
NEMA 3S: Everything NEMA 3R offers, but specifically designed to keep switches or devices operational even if ice builds up on the outside of the enclosure. So, they are commonly used in cold climates.
NEMA 4: This rating covers both indoor and outdoor locations. It shields against splashing water, hose-directed water, and rain. So, it is often used in washdown areas or outdoor settings that require watertight safeguards.
NEMA 4X: NEMA 4 has protection against corrosion. It is great for food processing plants, chemical facilities, places near the coast, and wherever else there is a risk of rust.
NEMA 5: Used for indoor environments where dust, lint, or fibres are present in the air. It keeps solid particles out and provides moderate relief against moisture. Therefore, it is frequently used within textile plants and warehouses.
NEMA 6: Provides protection against heavy water exposure as well as short-term submersion, but not deep or long-term water exposure. It was designed for areas that may experience temporary flooding or need protection from being submerged for short time periods.
NEMA 6P: Well, it is stronger than NEMA 6. This allows for long-term submersion and is recommended for very harsh or wet environments. So, it is excellent for underground equipment or equipment submerged in water.
NEMA 12: Widely used in factories. Because it protects from dust as well as dirt falling from above and drizzling non-corrosive liquids such as oil and coolant. Therefore, enclosure type 12 is frequently used in automation control panels and in industrial machinery.
NEMA 13: Almost identical to NEMA 12 with the addition of protection against splashing and spraying of non-corrosive fluids like water. Useful in areas that periodically undergo light maintenance or where oil is sprayed on machinery.
Selecting the proper NEMA rating ensures the safety and longevity of the system. Always think about the surrounding environment, dry, wet, dirty, or containing chemicals, before making the choice.
3) Material Guide Based on NEMA Ratings
Selecting the most appropriate material in regard to the electrical enclosure is dependent upon the environment and the NEMA rating classification required. Below is a table that recommends materials and their corresponding NEMA ratings.
a) Stainless Steel (304/316)
Stainless steel is tough, resistant, and does not corrode, which makes it ideal for brutal surroundings. It is used in NEMA 4x-rated enclosures to protect industries such as food processing, chemical manufacturing, and marine applications.
Type 316 is much more resistant to corrosion than Type 304. It is thus more suitable for such environments where there is saltwater exposure.
b) Aluminium
Aluminium is light in weight, does not rust, and is relatively cheap. It’s often found in NEMA 3R or NEMA 12 rated enclosures that protect against rain and light dust. Aluminium works well in outdoor applications such as telecom cabinets and indoors, where chemicals are not present.
Moreover, its ability to withstand corrosion in milder outdoor conditions also makes it useful as a versatile material.
c) Carbon Steel
Carbon steel is widely known for being strong and inexpensive. It is used in a NEMA 1 or NEMA 12 enclosure. However, untreated carbon steel rusts easily. However, the steel is best used in dry indoor settings or industrial environments where moisture is not problematic.
With a coating, the steel can be used where there is dust, dirt, or oil.
d) Polycarbonate / Fibreglass Reinforced Plastic (FRP)
Polycarbonate and fibreglass reinforced plastic (FRP) do not conduct electricity and resist corrosion extremely well. Those materials are found in NEMA enclosure type 4X, which are suitable for outdoor and chemically exposed places.
Apart from this, they are long-lasting and require no maintenance, which makes them ideal for use in chemical processing plants and wastewater treatment plants.
e) Plastic
Plastic is lightweight and does not corrode, so it is used for NEMA 1 or NEMA 4 rated enclosures. It is ideal for light-duty work indoors and in places that require protection from dust and water.
This guide assists you in selecting a material that ensures enclosures provide optimal protection for the equipment.
4) Indoor vs. Outdoor Use: Material Considerations
The geographical location or the indoor/outdoor placement of the particular structure is going to dictate the choice of material for the electrical enclosure. Some of the considerations are outlined below:
Outdoor Enclosures
It is obvious that they have to withstand harsh environmental impacts such as UV exposure, snow, rain, and in particular salty sea water. If adequate materials are not used, corrosion, rust, and general degradation of the enclosure will occur.
Thus, stainless steel (NEMA 4X) and fibreglass can be employed. You know stainless steel is resistant to corrosion and rust, even with exposure to salty air, plus fibreglass is both lightweight and resistant to UV radiation and moisture.
Great that these materials guarantee durability, especially for the outdoor telecom cabinets, which are required to be serviced in harsh weather conditions.
Indoor Enclosures
The case of Indoor enclosures is different, the conditions are relatively less extreme. There is no requirement for moisture or UV blockade, but they need protection against grease, dirt, and dust.
To be honest, for indoor applications, carbon steel is often used for NEMA 12-rated enclosures as it is strong and inexpensive when compared to other materials. In addition, it provides protection from dust and non-aggressive contamination. It makes it useful for indoor automation control systems.
One has to ensure that the carbon steel is coated; otherwise, in a humid environment, the steel will rust.
Impact of Chemicals, Temperature, and Washdowns
Chemical exposure, extreme temperatures, and washdowns, both indoor and outdoor, have a dire impact on the longevity of enclosures’ lifespan. The use of chemicals contributes to the thinning and erosion of metals and plastics.
Thus, enclosures, especially in industrial plants or factories, will require additional protection. Expansion and contraction of some materials due to temperature fluctuations may compromise some of the materials’ structural integrity as well. During the washdown of food and pharmaceutical products, there is a need for enclosures with greater protection against corrosion and water pressure. It often employs NEMA 4x-rated materials.
These delimitations allow you to choose the proper materials which guarantee maximum lifespan and reliability of the electrical enclosures in the particular environment.
5) Choosing the Right Enclosure: Practical Tips
To choose the appropriate electrical enclosure, you must take into consideration some key factors which make the process more complex. Here are some practical steps to find the best option:
? Assess Environmental Factors: Evaluating the environment is of utmost importance as the starting point. So, pay attention to the presence of moisture, dust, chemicals, and the surrounding temperature. You know enclosures that undergo constant exposure to high humidity or extreme temperatures require stainless steel or fibreglass.
? Evaluating Protection Needs: Establish your desired level of protection. For instance, if your enclosure will be subject to rainfall or chemical exposure, select materials with a NEMA rating of 4X or higher. If your requirements are not as demanding, NEMA 12 ratings for dust and oil resistance will be acceptable.
? Select a Suitable Material: The material surrounding the enclosure is of importance. In harsh environments, stainless steel is best, while aluminium is suited for moderate conditions. Polycarbonate is lightweight and resistant to corrosion, but does not possess the strength metals do, making it less desirable.
? Joint Material and NEMA Rating: The NEMA rating must correspond with the material and its protective abilities. As an example, fibreglass or stainless steel NEMA 4X enclosures outdoor harsh weather, while NEMA 1 carbon steel enclosures are better placed in dry indoor environments.
? Weight vs Protection: Analyse the balance between weight and protection. Less cumbersome materials, such as aluminium, are easier to handle, but do not stand up as well as more dense materials like fibreglass or stainless steel.
? Cost vs Durability: Analyse the budget. The price for protection is often higher for stainless steel. Consider the cost of the intended lifespan of the enclosure.
? Consider Custom Solutions: Should you have specialised needs, engage enclosure companies to develop custom solutions that suit your needs.
? Compliance and Standards: Check that the enclosure complies with the standards relevant to your industry. Compliance with safety and protection standards is fundamental in ensuring the system operates reliably.
6) FAQS
1. Can any material meet any NEMA rating?
Not every material can satisfy a NEMA rating. Certain protections must be offered, such as moisture, dust, or corrosion, in order to achieve a certain NEMA rating.
2. Are polycarbonate enclosures durable in harsh environments?
While polycarbonate enclosures are generally durable, they may not be suitable in extreme conditions. They are impact and corrosion-resistant, but in highly chemical or extreme temperature environments, alloys like stainless steel perform better.
3. When is stainless steel necessary?
Stainless steel is essential in extreme environments like outdoor locations where moisture, chemicals, or salts are present. It has exceptional corrosion resistance and is best used for NEMA 4X applications.
4. Is aluminium OK for marine use?
Aluminium is acceptable for marine use, but it does not have as much corrosion resistance as stainless steel. In severe marine environments, stainless steel or fibreglass may be more appropriate.
7) Conclusion
Selecting the proper enclosure is key to extending the life and protecting your equipment. So, it’s important to understand NEMA ratings and how they relate to materials, which include stainless steel, aluminium, and polycarbonate. For both indoor and outdoor use, moisture, dust, chemicals, and temperature extremes all need to be considered.
Using reputable suppliers such as Saipwell ensures you get the right materials and ratings needed for your enclosures. Saipwell caters to a variety of industries, providing an extensive catalogue of tailored, high-quality solutions to keep your equipment safe and functional. To get the desired rating enclosures, you can contact us right now!
