What does NEMA 4X protect against?

NEMA 4X is a watertight, dust-tight outdoor or indoor rating that also resists corrosion. It withstands windblown dust, rain, splashing, hose-directed water and ice formation, making it common for food, marine and chemical environments.

How does NEMA map to IP ratings?

The mapping is approximate because the tests differ. As a guide, NEMA 1 ≈ IP10, NEMA 12 ≈ IP52, NEMA 4 ≈ IP56 and NEMA 6P ≈ IP67. A NEMA rating can be converted to IP, but an IP rating cannot be assumed to meet NEMA without retesting.

What is the difference between NEMA 4 and NEMA 12?

NEMA 12 is an indoor type that keeps out falling dirt, dripping liquids and dust, but is not rated for hose-down water. NEMA 4 adds full watertight, hose-directed and outdoor protection, so it suits washdown and weather-exposed locations.

Which NEMA types are explosion-proof?

Types 7, 8, 9 and 10 are hazardous-location ratings for atmospheres with flammable gases, vapours, dust or mining methane. They are distinct from the general-purpose types 1–13 in this table and require certified equipment.

Does this reference run offline?

Yes. The NEMA 250 type definitions are built into the page and filtering happens entirely in your browser. Nothing is uploaded or stored.

What is the NEMA Enclosure Rating Reference?

Reference table for NEMA electrical enclosure types 1 to 13, listing indoor/outdoor use, the protection each offers against dust, water, oil and corrosion, and the nearest IEC IP equivalent. It runs free in your browser on Gera Tools, with nothing uploaded.

NEMA Enclosure Rating Reference

Name: NEMA Enclosure Rating Reference
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

What NEMA enclosure ratings cover

The NEMA 250 standard classifies electrical enclosures by the conditions they withstand: dust, water, oil, ice and corrosion, for indoor or outdoor use. Unlike the IEC IP system, NEMA ratings also account for corrosion resistance, gasket ageing and external icing, so the two systems are related but not identical.

How it works

Each NEMA type defines a set of pass/fail environmental tests. Higher general-purpose numbers do not strictly stack, but broadly: type 1 is basic indoor, type 3R adds rain and ice, type 4 is fully watertight, type 4X adds corrosion resistance, type 6 adds temporary submersion, and type 12/13 cover indoor dust, drip and oil. Suffix letters carry meaning — X is corrosion-resistant, R is rainproof, P is prolonged submersion.

This reference lists the general-purpose types with their indoor/outdoor use, the hazards they exclude, and the nearest IP equivalent. The search box filters all columns.

Quick selection guide by application

Application	Recommended NEMA type
Indoor electrical panel, clean room	Type 1
Outdoor meter or disconnect, rain/ice	Type 3R
Outdoor with wind-blown dust	Type 3 or 3S
Washdown area, outdoor (non-corrosive)	Type 4
Food plant, marine, chemical (corrosive)	Type 4X
Temporary submersion (flood zones)	Type 6 or 6P
Indoor with oil mist, dust, drip	Type 12
Indoor with oil splash, spraying liquids	Type 13

Understanding the suffix letters

The suffix letters after a NEMA number are part of the rating and carry specific meaning:

X — corrosion-resistant. The enclosure uses stainless steel, fiberglass, or an equivalent material that resists attack from moisture and corrosive agents. Type 4X is the same as Type 4 (watertight) but adds this corrosion protection.
R — rainproof. Added to certain outdoor types to indicate specific resistance to falling rain and ice. Type 3R is commonly used for outdoor meter bases and disconnects where full watertightness is not needed.
P — prolonged submersion. Type 6P can withstand extended periods underwater, unlike Type 6 which handles only temporary submersion.
S — sleet or ice resistant on external parts. Type 3S and 3RX are examples; the S means the external hardware (hinges, handles) can operate after ice forms on them.

NEMA versus IP ratings: the right way to cross-reference

The IEC IP (Ingress Protection) system uses two digits to rate solid particle exclusion and liquid ingress resistance. The comparison with NEMA is approximate because the test methods differ:

NEMA tests include corrosion resistance, icing, and gasket durability tests that IP ratings do not address.
IP ratings cover a wider range of liquid ingress levels with more granularity than NEMA.
A product tested to NEMA 4X can generally be stated to also meet IP66, but an IP66-rated product from outside North America cannot be assumed to meet NEMA 4X without separate NEMA testing.

The direction of the conversion that is safe: NEMA to IP as a statement of minimum equivalent. The unsafe direction is IP to NEMA — never assume an IP rating implies NEMA compliance without documented testing.

Tips and example

For an outdoor control box exposed to rain and washdown in a food plant, choose NEMA 4X: watertight, hose-resistant and corrosion-resistant. For a clean indoor panel that only needs dust and drip protection, NEMA 12 is sufficient and cheaper. When sourcing parts internationally, treat the IP column as a guide only — convert NEMA → IP, never the reverse.