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Comparing NEMA and IP Part 2: NEMA Enclosure Types

NEMA enclosures protect against the elementsLast week, we covered IP codes, what kind of protection it offers, and what all the numbers mean. An important observation is, that IP codes and NEMA protection types cannot be used interchangeably.

Specifically, a NEMA protection type may be able to substitute for an IP code, but IP cannot take the place of a NEMA specification.

Why? Because NEMA protection types specify much more than IP codes. The two rating systems, as covered in part 1 of this series, come from two different standards – the IEC 60529 for IP codes, and NEMA 250 for, you guessed it, NEMA protection types. As stated in NEMA documentation:

IEC 60529 is NOT a ‘product standard’ and does not cover enclosure requirements other than the ‘degree of protection’ provided. For instance, IEC 60529 does not specify the corrosion protection and other environmental operating requirements and tests defined in NEMA 250.

Beyond limiting the ingress of solid objects, water, and preventing human access to hazardous parts, NEMA 250 specifies:

  • Construction requirements
  • Door and cover securement
  • Corrosion resistance
  • Effects of icing
  • Gasket aging and oil resistance
  • and Cooling effects

So what are the ratings, and what do they specify? These tables may help:

Table 1

Indoor Non-Hazardous Locations

Provides a Degree of Protection Against the Following Conditions Type of Enclosure
1 2 4 4X 5 6 6P 12 12K 13
Access to hazardous parts X X X X X X X X X X
Ingress of solid foreign objects (falling dirt) X X X X X X X X X X
Ingress of water (Dripping and light splashing) ... X X X X X X X X X
Ingress of solid foreign objects (Circulating dust, lint, fibers, and flyings) ... ... X X ... X X X X X
Ingress of solid foreign objects (Settling airborne dust, lint, fibers, and flyings) ... ... X X X X X X X X
Ingress of water (Hosedown and splashing water) ... ... X X ... X X ... ... ...
Oil and coolant seepage ... ... ... ... ... ... ... X X X
Oil or coolant spraying and splashing ... ... ... ... ... ... ... ... ... X
Corrosive agents ... ... ... X ... ... X ... ... ...
Ingress of water (Occasional temporary submersion) ... ... ... ... ... X X ... ... ...
Ingress of water (Occasional prolonged submersion) ... ... ... ... ... ... X ... ... ...

Table 2

Outdoor Non-Hazardous Locations

Provides a Degree of Protection Against the Following Conditions Type of Enclosure
3 3X 3R 3RX 3S 3SX 4 4X 6 6P
Access to hazardous parts X X X X X X X X X X
Ingress of water (Rain, snow, and sleet) X X X X X X X X X X
Ice Covered ... ... ... ... X X ... ... ... ...
Ingress of solid foreign objects (Windblown dust, lint, fibers, and flyings) X X ... ... X X X X X X
Ingress of water (Hosedown) ... ... ... ... ... ... X X X X
Corrosive agents ... X ... X ... X ... X ... X
Ingress of water (Occasional temporary submersion) ... ... ... ... ... ... ... ... X X
Ingress of water (Occasional prolonged submersion) ... ... ... ... ... ... ... ... ... X

You may have noticed a bit more information here than on the IP codes table. Again, it is because the NEMA rating systems covers more than just the ingress of water and dirt.

To give credit where credit is due, IP codes are more detailed in their specification on human protection, and the ingress of solids objects and water. However, they do not specify protection against oils, coolants, corrosive agents, or ice.

As stated in part 1 of this series, it is best to simply understand the application, and why the protection rating has been specified. Only then can an IP code or a NEMA enclosure type be effectively converted, if possible.

For example, if a NEMA 6P enclosure type has been specified only because it can withstand prolonged immersion in water, then there is an equivalent IP code for that – IP68. As with everything in the world of sensors and process control, it depends on the application.

We will wrap this up with a conversion chart between IP and NEMA ratings for a generic guide. Again, this is technically impossible – but may be achieved in certain circumstances with a thorough understanding of the application.

Let us know if you have any questions about NEMA enclosure types and how they relate to your application. You can drop us on our contact page.

If you have experience in these matters, don’t hold back! We welcome your commentary.

Source: nema.org

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