Electrical enclosures are boxes that are designed to contain electrical circuitry, components, and switches. At NJ Sullivan, enclosures are typically constructed from Formed continuously seam welded 12 gauge steel, carbon steel, aluminum, or stainless steel. Enclosures are usually for commercial use, designed to contain components that aren’t accessed daily and are usually powder coated to help prevent corrosion.
To ensure that electrical enclosures are constructed to a safe, consistent standard, the National Electrical Manufacturer’s Association (NEMA) has assigned a series of codes that designate how well the enclosures stand up to dirt, water, wind, and cold. These NEMA ratings allow builders and electricians to make sure that their jobs are up to code. They also allow you to mix and match components from multiple manufacturers, which wouldn’t be possible if there weren’t a universal standard.
Enclosures are available in a variety of sizes. They can be large, walk-in cabinets, or small, wall-mounted boxes that only contain a few components. If you’re mounting one enclosure inside a larger enclosure, it’s important that both enclosures have the same NEMA rating. Otherwise, you’re very likely to be in violation of code, which can lead to delays and added expenses.
But what do these NEMA ratings actually mean? Here’s a quick explanation of some of the more common specifications:
- NEMA Type 1 enclosures are designed for indoor use. They provide a minimal level of water protection, but they’re primarily designed to keep dirt and dust out of your wiring. They’re also reinforced to keep unauthorized employees from getting inside and injuring themselves.
- NEMA Type 3 enclosures are engineered for outdoor use. They’re resistant against rain, sleet, and wind-driven dirt. The outside of NEMA Type 3 enclosures are treated or powder-coated to resist corrosion and ice buildup.
- NEMA Type 3R enclosures are a variant of Type 3 enclosures that add extra layers of protection with an internal gasket and ventilation louvers.
- NEMA Type 4 enclosures add even more protection and are designed, to protect against high-pressure jets of water from a hose. This makes them easier to clean than Type 3 enclosures, so they’re ideal for applications where the cosmetic appearance is important.
- NEMA Type 4X is a subtype of Type 4, which is also resistant to corrosion by being constructed from stainless steel. The NEMA Type 4X also has an internal gasket and is considered a weatherproof enclosure. If your enclosure will be subject to road salt or other damaging chemicals, it’s a good idea to upgrade to Type 4X.
Please click the link below for a full list of NEMA and UL type enclosures, ratings and descriptions.