Prior to standardization, manufacturers used vague terms such as “waterproof” or “dust-proof,” which were not standardized or easily quantifiable. It was difficult to discern if a product’s qualities were true in how they were described.
This article outlines two different systems of ratings that quantify degrees of protection against the elements.
IP Ratings
In 1976, the International Electrotechnical Commission (IEC) established IP Codes under IEC 60259. IP (Ingress Protection) ratings measure how resistant a device is against solid materials and water.
An IP rating is made up of two digits, the first indicating protection against solids on a scale of 0-6. The second digit indicates protection against water on a scale of 0-9.
IP Ratings Chart
Solids
| First Digit | Protection Level |
| 0 | No protection. |
| 1 | Protection against solid objects that are greater than 50 mm. |
| 2 | Protection against solid objects that are greater than 12.5 mm. |
| 3 | Protection against solid objects that are greater than 2.5mm. |
| 4 | Protection against solid objects that are greater than 1 mm. |
| 5 | Protection against dust, limited ingress of dust permitted. The dust will not interfere with operation. |
| 6 | Dust tight. No ingress of dust. |
Water
| 2nd Digit | Protection Level |
| 0 | No protection. |
| 1 | Protection against water drops. |
| 2 | Protection against water drops at a 15-degree angle. |
| 3 | Protection against water drops at a 60-degree angle. |
| 4 | Protection against water splashing from any angle. |
| 5 | Protection against water jets from any angle. |
| 6 | Protection against powerful water jets. |
| 7 | Protection against the effects of temporary submersion in water (up to 30 minutes, up to 3 feet). |
| 8 | Protection against the effects of permanent submersion in water (up to 13 feet). |
| 9(K) | Protection from close-range, powerful, high pressure/high temperature water jets. |
Commonly Used IP Ratings in Electronics
- IP67: This rating indicates that the device is resistant to dust and can be submerged into up to 1 meter of water for a limited time (3 feet, 30 minutes) without damage.
- IP68: This is the 2nd highest IP rating for electronic goods. Dust-tight and can be continuously submerged in water.
- IP69(K): The high 9 rating denotes harsh environments and regular water exposure. Items that are made for industrial manufacturing, food processing, and road vehicles will often have this rating. The “K” that is sometimes included in this rating is derived from the German word “Kondeswasser” (condensation water).
NEMA Ratings
The National Electrical Manufacturers Association (NEMA) has its own set of ratings that defines the degree of protection from environmental conditions.
This set of guidelines was created in 1926 when the Electric Power Club and Associated Manufacturers of Electrical Supplies merged, with the goal to standardize the emerging market of electrical products and provide clearer information to consumers.
NEMA ratings indicate the degree of protection an enclosure offers against hazards such as dust, water, oil, and corrosive materials, and functionality across various industrial applications.
A NEMA rating is notated, or referred to as “NEMA”, followed by the number that denotes the degree of protection, such as “NEMA 5” or “NEMA 12K.”
NEMA Ratings Chart
| 1 | Dust-tight. |
| 2 | Can be exposed to falling dirt and dripping water. |
| 3 | Weather-resistant. |
| 3R | Weather resistant, except for wind-blown dust. |
| 3S | Weather resistant and can be used in icy conditions. |
| 3X, 3RX, 3SX | Has the properties of NEMA 3, but with additional corrosion protection. |
| 4 | Watertight. |
| 4X | Watertight, with corrosion resistance. |
| 5 | Dust-tight, for indoor use. |
| 6 | Submersible for short periods of time. |
| 6P | Submersible, can withstand to be in water for longer periods of time. |
| 7 | For use in areas with specific hazardous conditions classified by the National Fire Protection Association (NFPA) as Class I, Division 1, Groups A, B, C, or D as defined in NFPA 70. For indoor use where explosion-proof capabilities are essential. |
| 8 | For use in areas with specific hazardous conditions classified by the National Fire Protection Association (NFPA) as Class I, Division 1, Groups A, B, C, or D as defined in NFPA 70. For indoor or outdoor use where explosion-proof capabilities are essential. |
| 9 | For use in areas with specific hazardous conditions classified by the National Fire Protection Association (NFPA) as Class II, Division 1, Groups E, F, or G as defined in NFPA 70. For indoor use where explosion-proof capabilities are essential. |
| 10 | Meets requirements of the Mine Safety and Health Administration (MSHA). |
| 11 | General purpose; protects against corrosion from liquids and gases. |
| 12 | Enclosures constructed without knockouts should protect against falling dirt and dust, with protection against the effects of water. General purpose, for indoor use. |
| 12K | Enclosures constructed with knockouts should protect against falling dirt and dust, with protection against the effects of water. General purpose, for indoor use. |
| 13 | General purpose, meets oil exclusion and rust resistance tests. |
NEMA vs. IP Ratings
In the United States, NEMA ratings are generally preferred. However, IP ratings are used internationally. NEMA and IP ratings are not necessarily equivalent to each other, as the higher numbers in NEMA ratings do not correspond with a higher degree of elemental protection.
Below is a chart outlining NEMA ratings and their IP equivalents.
| NEMA | IP (2-digit combination) |
| 1 | 10 |
| 2 | 11 |
| 3 | 54 |
| 3r | 14 |
| 3s | 54 |
| 4 and 4x | 56 |
| 5 | 52 |
| 6 and 6p | 67 |
| 12 and 12k | 52 |
| 13 | 54 |
In short, IP and NEMA ratings are key for ensuring the durability and safety of electrical products. While IP focuses on dust and water resistance, NEMA offers broader protection against a range of elements and hazards. Understanding these systems can help in making informed decisions about which products to purchase for an upcoming project depending on the environments in will be working under.
