Electrical enclosure ratings are fundamental factors when it comes to selecting enclosures for particular applications and locations. They define the environmental and safety conditions that an enclosure is built for, as well as its general suitability for certain types of electrical equipment. There are several key ratings to be aware of, as explained in this post.
Electrical Enclosure Rating
An electrical enclosure rating is a value assigned to an enclosure that defines the maximum environment conditions it can withstand. It can be a rating for temperature, humidity, corrosion, water ingress, impact or any number of other conditions.
Enclosure manufacturers use these ratings to communicate to customers what conditions their products are designed for. When selecting an enclosure, it’s crucial to ensure that it is suitable for the specific conditions it will be exposed to, as well as any electrical equipment that will be housed inside of it.
Types of Electrical Enclosure Ratings
There are several different types of electrical enclosure ratings that engineers can use to evaluate the suitability of an enclosure for a particular application. These are developed and published by different organizations, both regional and international. The most commonly used ratings are:
IP Enclosure Ratings
IP is the short form for Ingress Protection, and is a rating system used to define the level of protection an enclosure offers against solid objects and liquids. This enclosure standard is published by the International Electrotechnical Commission (IEC)
The IP enclosure rating system has two digits, with the first digit representing the level of protection against solids, and the second digit representing the level of protection against liquids.
For example, an IP54 rated enclosure offers some protection against dust and water splashing from any direction. In contrast, an IP65 rated enclosure offers complete protection against dust ingress, and low pressure water jets from any direction.
When a digit it replaced by an X in the IP rating system, it means the enclosure is not rated for that particular protection level. For example, an IPX4 enclosure offers undefined protection against solids.
NEMA Enclosure Rating
NEMA is used is used for National Electrical Manufacturer’s Association. This enclosure rating system used to define the level of protection the enclosure offers against physical impact, water ingress and corrosion.
It’s good to note that NEMA does not test or certify enclosures. Rather, they publish voluntary standards that manufacturers can choose to follow.
The NEMA electrical enclosure ratings use numbers and letters to define the level of protection offered. And while there are many different ratings, the most common are NEMA 1 up to NEMA 13.
NEMA electrical enclosures are among the most common, given the standard’s adoption by many manufacturers. And because they offer protection against a wide range of environmental conditions, NEMA enclosures can be used in a variety of applications.
UL Enclosure Rating
UL is the short form for Underwriters Laboratories. This is a global safety consulting and certification company. They have developed several standards for products, including electrical enclosure ratings.
The UL rating system classifies enclosures according to their suitability for specific types of equipment and enforces these ratings through a certification program.
This program requires manufacturers to submit their products for testing by independent laboratories to ensure they meet the relevant standards.
CE Enclosure Rating
The CE enclosure rating is a mandatory conformity mark for products sold within the European Economic Area. It is an indication that a product meets the requirements of all relevant EU directives.
In order to affix the CE mark to an enclosure, the manufacturer must carry out a self-declaration process to show that the product meets all the necessary requirements.
RoHS Enclosure Rating
RoHS stands for Restriction of Hazardous Substances. This is a directive that was introduced by the European Union and that placed restrictions on the use of six hazardous materials in the manufacture of electronic and electrical products
To be compliant with RoHS, an enclosure must not contain more than 0.1% of any of the restricted materials. These include lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers, among other substances.
RoHS electrical enclosure ratings are complied with by different EU countries independently. Other regions, such as Asian countries, have also introduced their own RoHS-inspired directives.
NEMA vs. IP Enclosure Ratings
Both NEMA and IP enclosure ratings are used to assess the suitability of an enclosure for a particular application by its ability to protect against water ingress and dust. However, there are some key differences between the two systems.
- While the IP rating system is governed by the IEC, the NEMA rating system is published by the National Electrical Manufacturer’s Association.
- NEMA rating only defines standards for electrical enclosure ratings, while IP rating can be applied to other types of electrical devices or products.
- Unlike NEMA rating that usually uses one digit to define the level of protection against water ingress, IP rating uses two digits. The first digit defines the level of protection against solids, while the second digit defines the level of protection against liquids
Choosing Enclosure Rating
Before settling for a particular enclosure rating, it’s important that you consider the conditions in which it will be used. This will help you to determine the level of protection it requires. Some of the factors that you need to consider when electrical enclosure ratings include:
- The type of electrical equipment that will be placed in the enclosure
- The environment in which the enclosure will be used
- The level of protection that is required
You also need to consider the regulations and standards that apply to your industry or application. This will help you to choose an enclosure that meets all the necessary requirements.
Always look for an enclosure that has a higher rating than what you actually need. This will provide you with some margin for error and give you some leeway in case the conditions are harsher than anticipated.
Electrical enclosure ratings are an important factor to consider when choosing an enclosure. Ratings provide a way to assess the suitability of an enclosure for a particular application which, in turn, means that you can choose the right enclosure for the job. Note that different enclosures will use one or more of the rating systems that we’ve discussed in this article.