NEMA 4 vs. NEMA 12 Electronics Enclosure

WHICH ONE IS THE RIGHT OPTION?

The NEMA 4 and NEMA 12 are two most commonly confused electronics enclosure ratings. Several customers easily assume that they need a NEMA 4 for their engineering project, simply because it is one of the highest levels of protection for weatherproof cabinets. However, if the needs are not well identified, the user can spend too much on buying a NEMA 4 – and opt for a NEMA 12 instead.

When you want to choose electrical enclosures, there are two factors you should consider:
First, which environment will you use it in? Indoor or outdoor?
Second, what level of protection in that environment is required?

Once the customer recognizes their need to use an electronics enclosure for their engineering project, they should take into consideration exactly what type of protection is needed.

The National Electrical Manufacturers Association (NEMA) has successfully defined 13 different enclosure ratings to help you identify which type of enclosure will best protect your equipment in a given environment. Choosing the wrong rating can lead to premature failure, costly downtime, and even safety hazards.

Choose wrong level of protection could cost you a big Damage

It could cost you money, time, equipment and trust.

If you buy the wrong enclosure, you waste money and time. Make sure you understand the environment, the type of protection needed, and how you plan to install it before you purchase.

Many assume NEMA 4 is always best because it’s one of the highest protection levels. But if you only need dust and light splash protection indoors, a NEMA 12 will save you money without compromising safety.

Outdoor, hose‐directed spray, windblown rain or ice? Use NEMA 4.
Indoor, dust, light dripping or splashing, oil seepage? Use NEMA 12.

NEMA 4 Common Application

Typically used to protect IT networking cabinets, automated electronics, traffic‐signal controls, phone and cable distribution, and security/communications equipment.

Also used in packaging and material‐handling systems or any application exposed to windblown rain, splashing water, and freezing rain.

To Pass the Criteria

NEMA 4 TESTING REQUIREMENTS

Outdoor use requires protection against windblown dust and rain, splashing water and hose‐directed spray. The minimum NEMA 4 test is a 65 gal/min (246 L/min) fire hose spray for 5 minutes with zero water ingress.

NEMA 12 TESTING REQUIREMENTS

Indoor use only—expects dust, light dripping, and light splashing of non-corrosive liquids. The NEMA 12 test is a 30-minute drip test followed by a 30-psi (200 kPa) spray test, with no water ingress.

Protection Against the Following Conditions	NEMA 4	NEMA 12
Indoor Use	✔︎	✔︎
Outdoor Use	✔︎
Access to hazardous parts	✔︎	✔︎
Ingress of solid foreign objects
Falling dirt	✔︎	✔︎
Circulating dust, lint, fibers, and flyings **	✔︎	✔︎
Settling airborne dust, lint, fibers, and flyings **	✔︎	✔︎
Windblown dust, lint, fibers, and flyings	✔︎
Ingress of water
Dripping and light splashing	✔︎	✔︎
Hosedown and splashing water	✔︎
Rain, snow, and sleet ***	✔︎
Sleet ****
Occasional temporary submersion
Occasional prolonged submersion
Oil & Corrosion resistance
Oil and coolant seepage		✔︎
Oil or coolant spraying and splashing
Corrosive agents