I wanted to share some of my experience and knowledge of how to design enclosures that protect against water and debris. This inevitably brings up the issue of NEMA or IP standards, but sometimes there is confusion as to how these work. I’m writing this to give some direction to designers who are tackling this subject. For simplicity’s sake, I’m going to limit myself to NEMA, but the principles are exactly the same if you use IP, so this should still be relevant to you.
Before starting, I’d like to make the point that designers should clearly consider what they are trying to achieve.
Are they just looking to achieve environmental protection? Or are they trying to meet a formal requirement to achieve a NEMA standard (which may have been imposed by a customer or manager)?
I have seen thousands of custom enclosures come through Protocase with environmental resistance requirements, and most of these enclosure orders only need environmental protection. Our customers will often use NEMA standards to explain what they need their enclosure to do, such as offer a certain resistance to dust, dirt or water, but do not need to formally meet NEMA’s standards.
Occasionally, we do see a customer who needs to meet a formal NEMA requirement, which necessitates testing. Although Protocase does not offer testing of enclosures to verify NEMA requirements, some of our customers will send their enclosures to a third-party testing facility in order to receive formal certification that they have met requirements. In this case, the principles I describe below are the same.
The document “NEMA Enclosure Types” is put in place to promote standardized product specifications for electrical devices. Basically, the role of NEMA standards is to specify how an enclosure must perform to meet the classification. Specifically, NEMA standards deal with the following:
What NEMA does not do is prescribe how to design and manufacture an enclosure to meet performance specifications; I will cover that in the next section of this blog.
The NEMA standard covers a large number of enclosure types. However, our customers generally deal with the following subset of common types:
Note that all of these types will protect personnel against access to hazardous parts.
To see a full list of NEMA enclosure types, click here.
In the next section, I will discuss different families of enclosures and how they can protect against the environmental hazards addressed by NEMA.
This type of enclosure is very capable of protecting against dust, debris, and splashing or dripping water. Sheet metal enclosures can be designed to meet the requirements of NEMA Types 1, 2, 4, 4X and 5. However, if your enclosure requires immersion in water, this is not the best choice for you. Here are some guidelines:
If you’re looking for an enclosure that can be immersed in water, this is it. A CNC machined enclosure can be designed to meet NEMA Types 1, 2, 4(X) and 5. It can also be completely sealed, and with the proper O-rings or gaskets, made waterproof, sufficient to protect against deep liquid immersion and thereby meeting NEMA Type 6(P).
Keep the following in mind when designing this type of enclosure for water immersion:
We also offer a line of Customizeable Diecast Enclosures, which are off the shelf (OTS) cast enclosures and customize them for you. They can be watertight with the proper designing and seals and are very similar to our custom CNC Machined Enclosures. With minimum customizations or cutouts, along with the proper gaskets or O-rings, this enclosure type could meet NEMA Type 6(P). This type of enclosure will also meet NEMA Types 1, 2, 4(X) and 5 easily.
However, there are two major differences between OTS Cast and custom machined enclosures:
Thus, if you can live with the size and shape restrictions, a customizable diecast enclosure is the economical choice.
With this enclosure, as with custom machined enclosures, if you wish to achieve water tightness, you must ensure that every item that penetrates the enclosure (connectors, switches, etc.) are suitably watertight, and equipped with a gasket or sealed as necessary.
As I mentioned above, Protocase does not perform NEMA/IP testing within our manufacturing facility, but some customers opt to send their enclosures elsewhere for testing. To find out where you can get your enclosure tested, click here.
If this interests you and you have any questions NEMA or enclosure types, don’t hesitate to ask us by emailing email@example.com or by commenting below.
For more information on our materials and services, visit: www.protocase.com
Protocase delivers a whole new experience to engineers and design professionals by delivering custom enclosures, panels and parts with unmatched speed, simplicity and service.
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