Design Your Sheet Metal Fabricated Electrical Enclosure for the Right NEMA Protection Rating
Are you designing your electrical enclosure for the right protection rating?
The level of protection required for an electrical enclosure directly influences the materials and manufacturing methods used to make it , so it’s important to get it right.
As a manufacturer of UL 508a certified electrical sheet metal enclosures and custom enclosures adhering to National Electrical Manufacturer Association (NEMA) standards, Ameritex is committed to making the right electrical enclosures for every application.
Our goal is to help product developers avoid common mistakes in the design process, such as over- or under-engineering an electrical enclosure. Over-engineering can lead to unnecessary cost increases, while under-engineering leaves electrical components at risk and exposed to the elements.
Remember it is important to share your enclosure design project with your manufacturer if you intend to UL list your enclosure. In order to UL list an enclosure, it must meet the design criteria set forth in your manufacturers UL manual, or the design will have to undergo costly tests to certify the project. Things as simple as latch or hinge spacing can cause an enclosure to not pass a UL inspection. Alternatively, your manufacturer can self-certify a custom enclosure by testing and approving in house to design criteria for each type of enclosure.
Need a detailed refresher on NEMA protection ratings? We’ve got you covered!
NEMA 1 Enclosures
Designed for indoor use only, NEMA 1 enclosures provide just enough protection to prevent people from directly accessing hazardous electrical components. The circuit breaker boxes found in residential homes or indoor are perfect examples of this type of enclosure. Commercial applications include indoor marshaling panels that are destined for clean environments
NEMA 1 enclosures are commonly made from powder coated carbon steel with very minimal welding and little to no gasketing.
NEMA 3R and NEMA 3RX Enclosures
A step above NEMA 1 enclosures, NEMA 3R and NEMA 3RX enclosures are permitted for indoor or outdoor use. In addition to preventing access to hazardous electrical components, these types of enclosures protect against regular weather events like rain, sleet, and snow. NEMA 3RX enclosures have the added protection of being corrosion resistant as well. NEMA 3R enclosures can have features like louvers for ventilation. The design of the louver prevents rainwater from entering the enclosure but would not protect from pressurized water directed toward the enclosure.
Cost effective NEMA 3R and NEMA 3RX enclosures feature stitch or spot welding and are often powder coated to coordinate with the materials at the project site or safety requirements. To ensure corrosion resistance, NEMA 3RX enclosures require the use of aluminum or stainless steel.
NEMA 4 and NEMA 4X Enclosures
Designed for outdoor applications featuring sensitive equipment in potentially extreme environmental conditions, NEMA 4 and NEMA 4X enclosures offer significant water protection against anything from water hoses to rushing water. These types of enclosures are commonly found on rigs that must withstand frequent powerashing or in hurricane zones containing sensitive equipment.
Similar to NEMA 3RX enclosures, NEMA 4X enclosures are designed for corrosion resistance. Materials for NEMA 4X enclosures can be up to five times more expensive than materials for NEMA 4 enclosures, so we always advise our customers to consider whether corrosion resistance is critical for a particular application.
Common materials for these types of enclosures include powder coated steel for NEMA 4 and aluminum or stainless steel for NEMA 4X. We seam weld these enclosures all the way around to prevent any water from seeping through.
A common problem we see is engineers requesting a Type 4 or 4X enclosure but they have louvers for ventilation that do not meet the 4 or 4X design criteria. In this situation we suggest going to a cheaper 3R construction to reduce costs and lead time.
NEMA 12 Enclosures
NEMA 12 enclosures are designed for indoor use, with the purpose of protecting electrical components from small particles like dust and dirt. These types of enclosures are commonly found on industrial applications that contain the electrical components for a particular machine, like the back of a laser cutter or a water jet. You will find these cabinets in almost any indoor manufacturing environment.
When you request a quote for an electrical enclosure, be sure to tell us all the necessary features and applications so we can recommend the appropriate specifications. The Ameritex team can help you avoid common mistakes and make sure your enclosures are precisely engineered to the NEMA protection you need. At the same time, for UL-listed enclosures, we will confirm your design follows the criteria set forth in our UL manual for each Enclosure Type.
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