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NEMA, UL-Listed, and IP-Rated Junction Boxes

Electrical junction boxes, primarily utilized in housing electronic equipment, are usually listed with UL, NEMA, and IP ratings. But precisely what do these ratings mean? And what’s the difference? If you bought a junction box which was listed as dust-tight but features no rating within it, should you exercise caution?

When it comes to manufacturing, there are essentially three critical standards used in determining the various junction box grades and their degree of resistance to certain materials. However, while all serve a similar purpose, and each uses different parameters and approaches to define their standards.

Let us look at these ratings and what it all means.

NEMA Junction Box Ratings & What They Mean

Typically, NEMA-rated junction boxes are “enclosures” built for indoor or outdoor usage to offer a distinct level of protection against accidental contact of enclosed gadgets. They afford a certain protection level against circulating dust, fiber, and lint flying, not to mention against light liquid splashing.

NEMA is an acronym that represents the National Electrical Manufacturers Association, an organization established in 1962. This organization published guides and standards for equipment, with its members producing equipment that has adequately met these standards.

NEMA rated junction boxes are allocated a numerical rating between 1 and 13. This rating is non-progressive, and thus, higher number ratings don’t necessarily have all the perks of numbers below it. Instead, every number represents resistance to a given lot of varying environmental hazards. What’s more, there are letter ratings like S, X, and R that outline a certain degree of added resistance.

Some of the popular NEMA ratings and their meanings are as follows:

NEMA Type 1

These are boxes that are utilized in the protection of connections, controls, and terminations from personnel and objects. These junction boxes are used in places where you need to seal out dust, water, and oil.

NEMA Type 2

These junction boxes are for indoor usage to afford a level of protection against dirt and non-corrosive water (limited amounts). This is essentially against light splashing and dripping.

NEMA Type 3

These junction boxes are used outdoor and indoor to afford a certain level of safeguard against sleet, rain, and windblown dust, and keep the box undamaged by external ice formation on it.

NEMA Type 3R

These junction boxes are typically utilized in outdoor applications. They are used to afford protection against hail, the external formation of ice, falling rain, and snow. Indoors they safeguard against water (dripping).

NEMA Type 3S

They are designed to suit outdoor use to primarily afford a level of safeguard against sleet, windblown dust, rain, and external ice formation.

NEMA 4 Junction Boxes

These junction boxes are used in multiple applications where wash-down operations occur frequently or where there is the use of a machine tool cutter. These junction boxes also find use in applications where there is the use of pressurized water streams.

NEMA 4X Junction Boxes

These junction boxes are usually made of high-quality plastics or stainless steel. They are typically utilized in more adverse settings compared to regular NEMA 4 options. NEMA 4 boxes find use in applications that use caustic cleaners or corrosive materials.

NEMA 6P Junction Boxes

These are distinct junction boxes designed to suit both outdoor and indoor use. They offer a level of safeguard against water entry during a prolonged submission, although at a shallow depth.

NEMA 12 Junction Boxes

These junction boxes are used to protect enclosed gadgets against dust, oil, or water ingress. They are also commonly utilized for outdoor applications, mainly concerning electronic drive systems and automation control such as manufacturing applications.

NEMA 13 Junction Boxes

These junction boxes are purposed for indoor usage. They primarily offer a level of safeguard against water spraying, non-corrosive coolant, dust, or oil.

IP rated junction box

IP Junction Box Ratings & What They Mean

The International Protection Rating/Ingress Protection rating represents set codes utilized in defining certain protection levels. These codes comprise the IP prefix, accompanied by two numbers (digits) followed by an exclusive optional letter.

IP ratings (Ingress Protection) represent standards for the level of safeguard a junction box affords for users from various distinct factors such as water and foreign objects from harming the electrical components. They also offer protection for users from internal components.

IP ratings on junction boxes are used in measuring protection levels like preventing liquids and solid objects from intruding an enclosure. Solid objects are inclusive of debris, dust, and body parts of personnel. As for liquids, it involves moisture, water, and oils.

As previously mentioned, IP ratings boast two numbers: digit rating outlining the ability of the enclosure to safeguard against foreign solid object ingression; and the second, a digit outlining the degree of protection against liquids ingression.

First Digit: Protect Against the Entry of Foreign Items
  • Solid objects > 12.5 mm: (2)
  • Limited ingress, dust-protected: (5)
  • No ingress, dustproof: (6)
Second Digit: Safeguard Against the Entry of Water
  • No protection: (0)
  • Water sprayed equal to 15° from a vertical: (2)
  • Water sprayed from virtually any direction: (4)
  • Low-pressure water jets projecting water from any direction: (5)
  • High-pressure water jet projected water (any direction): (6)
UL listed stainless steel electrical box

UL Listed Junction Box Ratings & What They Mean

UL is an acronym for Underwriter Laboratories, an independent safety certification organization established in 1894 that sets safety and quality standards for junction boxes containing high voltage equipment and industrial control panels among others.

Type 1

Designed for indoor use to afford a level of safeguard against personnel contact with internal components as well as against a limited falling dirt amount.

Type 2

For indoor usage to afford a level of protection against dirt and falling water (limited amounts)

Type 3

IP-rated junction boxes are used outdoor and indoor to provide a certain level of safeguard against sleet, rain, windblown dust, and keep the box undamaged by external ice formation on it.

Type 3R

Outdoor/indoor usable junction boxes to offer a level of safeguard against falling sleet and rain. The box can also not be damaged by external ice formation on it.

Type 3S

Junction boxes for outdoor/indoor usage that offer a certain protection level against the entry of rain, sleet, and windblown dust. These boxes can also not be harmed by the formation of ice on it.

Type 4

Outdoor/indoor use to afford a level of safety against the entry of hose-directed or splashing water, windblown dust, and rain. Keep the junction box unharmed by ice formation on it.

Type 4X

Junction boxes for outdoor/indoor usage to afford a level of safeguard against windblown dust, rain, hose-directed, and splashing water. Also, it protects it from damage by external ice formation on it.

Type 6 Junction Boxes

Outdoor/indoor usage to afford a level of protection against water entry during limited depth temporary submersion. It is undamaged by external ice formation.

Type 6P

Outdoor/indoor usage to offer a level of safeguard against water ingress during prolonged immersion, but relatively shallow depth.

Type 11

Junction boxes designed for outdoor usage to afford a level of safeguard for the enclosed gadgets against corrosive effects from corrosive gases and liquids, by oil submersion.

Type 12

Junction boxes designed for indoor use to offer a level of safety against falling dirt and dust, as well as dripping liquids (non-corrosive).

Type 12K

Junction boxes/enclosures designed to afford a certain level of safeguard against dripping non-corrosive liquids, falling dirt, and dust.

Type 13

Distinct junction boxes for indoor to offer a protection degree against spraying water, dust, non-corrosive coolants, and oil.

Difference Between NEMA, UL, And IP Rated Enclosures

Since all these organizations set exclusive safety standards, it is inevitable that some of the standards effectively overlap. Nonetheless, these ratings have been independently established, and therefore the standards of these three organizations are varied. These ratings, however, are centered on similar performance expectations and application descriptions.

Even so, the significant difference between these three standard sets is primarily in the testing area. Essentially, IP and NEMA ratings are ideally “self-certifying”. This means that the manufacturers can typically design products to satisfy the standards and subsequently specify this rating devoid of any certification or approval of any third-party agency.

On the contrary, the UL junction box ratings require that the manufacturers systematize independent testing of their distinct standard compliance by use of independent evaluators.

Your Trusted Source for UL, NEMA, And IP Rated Junction Boxes

As such, if you need a junction box and are unsure which one best suits your applications, hopefully you now have a more informed understanding of the different types of junction box ratings. This way, you can make a better judgment of the electrical enclosure you should purchase to ensure it effectively safeguards the various components within.

If you are looking for a junction box or assistance finding the right one, we are here to aid you in landing the best solution. West Tool Enclosures fabricates and designs quality IP, UL, and NEMA rated junction boxes to your precise specifications, that effectively meets your stated lead times.

What’s more, we believe that by taking care of your specific junction box needs as you are configuring that which goes into it, we will save you money, time, and frustrations. Be sure to contact us, and we will be certain to deliver you the ideal enclosure to suit your needs and applications.