I have to install two new pieces of equipment in our industrial facility. One system will be used outdoors and one will be used indoors. An electrician told us that we have to use a particular enclosure to house the wiring for both systems, and they have to be NEMA-rated. I’ve heard the term many times, but I’m not exactly sure what NEMA means and the difference between each rating. I’m hoping you can clarify.
LET'S BREAK IT DOWN:
If you’re in the market for a motorized crane or your facility already uses one, you’ve probably heard the term “NEMA rating”. In fact, several readers have emailed us wondering what determines NEMA ratings, and the answer to that question is: NEMA does.
NEMA stands for the National Electrical Manufacturers Association, which was formed in 1926 to set standards for companies producing electrical products. NEMA enclosure ratings actually apply to any type of electrical equipment or wiring that’s installed outdoors or in an industrial facility.
Originally, NEMA set out to ensure the quality of electrical devices, components, and wiring. But, as technology has developed over time, so too has the need to protect it. Now, electrical components like controls, vulnerable devices, and wiring need protection from the application and environment in which they are used. The best way to provide that protection is by housing them in an enclosure or a cabinet.
Although NEMA is not responsible for electrical enclosures, they did develop a rating system to grade and regulate them. Since then, NEMA ratings have become the standard for enclosures of all kinds. Each NEMA rating was developed to match a specific application and environment, which helps to ensure that you’re using the right enclosure for your operation. And, there’s a good reason for that.
NEMA-rated enclosures perform a very important function: controlling ingress and egress. Ingress is defined as a substance’s ability to enter a structure or space—in this case, an electrical enclosure. Egress, on the other hand, is defined as a substance’s ability to escape a structure or space. Although most NEMA ratings focus on blocking ingress (preventing a substance from entering your electric enclosure), there are a few that also work to block egress (preventing a substance from escaping your electric enclosure). It’s essential to choose the right NEMA rating for your application in order to protect your electrical components and wiring. Here’s a breakdown of the most commonly used NEMA ratings, and what they were designed to do:
NEMA-RATED ENCLOSURES FOR HAZARDOUS LOCATIONS:
NEMA 7 and NEMA 10 enclosures are both designed to contain internal explosions with out causing external hazards. NEMA 8 enclosures are designed to prevent combustion in oil-immersed equipment, while NEMA 9 enclosures prevent the ignition of combustible dust. These particular enclosures are defined by the National Electric Code® (NEC) and National Fire Protection Association (NFPA).
Here’s how it works: the National Electric Code (NEC) is the benchmark for safe electrical design, installation, and inspection to protect against electrical hazards. NFPA is best known for its sponsorship of the NEC, and their standard for electrical safety in the workplace, known as NFPA 70. In layman’s terms, NFPA 70 is an acronym used for electrical and fire safety in the workplace, and it addresses the installation of electrical conductors, signaling conductors, and optical fiber cables in commercial, residential, and industrial occupancies.
The demand for electrical devices has far surpassed other means of motive power. As the use of electrical products continues to grow, so too does the need for manufacturing regulations for electrical safety. NEMA has established a simple categorization process that ensures compatibility between devices, promotes worker safety, and continues to develop new standards for the constantly evolving electrical industry.