NEMA rating and IP rating: Explain the difference between the two namesFor optimal safety and performance, electrical equipment needs to be kept away from the environment. NEMA rating and IP rating both indicate the protection level of the equipment against external conditions (from falling dust to waves). The two names differ in method, parameter, and category.
When selecting a pressure sensor or transmitter, an important factor to consider is the extent to which its housing or enclosure protects the sensor from elements and the possibility of explosion. Common and seemingly harmless environmental conditions, such as dust or moisture, can cause errors or malfunctions, both of which can have a negative impact on performance and safety.
Both organizations make it easy to understand the protection levels of products. The National Electrical Manufacturers Association (NEMA) has proposed many NEMA enclosure types, commonly referred to as "NEMA ratings," specifically for electrical equipment. The International Electrotechnical Commission (IEC) has created a digital system to classify almost any type of project, covered or surrounded. The Ingress Protection (IP) code not only covers the electronic enclosure, but also only considers solids and liquids.
These rating systems are similar in the sense of classifying the quality and quantity of intrusions. However, they use different test parameters, so they cannot be directly compared or easily converted. In addition, the IP rating only involves access, while the NEMA rating is more comprehensive, taking into account other factors such as corrosion and the physical location of the instrument.
What is NEMA rating?
NEMA ratings widely used in the United States are based on the NEMA 250 standard "Enclosures for Electrical Equipment (1000 Volts Maximum).". They represent the protection level of the equipment, ranging from falling dust to corrosive media. All NEMA ratings assume that enclosures protect personnel from hazardous components.
NEMA grades 1-6 and 12-13 are for non hazardous locations, Type 11 deals with corrosion, Type 7-10 complies with enclosures for hazardous (explosive) locations, and also contains other industry guidelines, namely Underwriters' Laboratories (UL) Class I or II requirements and Mine Safety and Health Administration (MSHA) standards. The following table summarizes the most common NEMA ratings:
NEMA enclosure type
score | Equipment location | Enclosure protection from…… |
NEMA 1 | within four walls | · fallen dust |
NEMA 2 | within four walls | · fallen dust · Drips and light splashes |
NEMA 3 | Indoor/outdoor | · Falling dust, wind dust · Rain, sleet, snow |
NEMA 3R | Indoor/outdoor | · fallen dust · Rain, sleet, snow · Damage caused by external icing |
NEMA 3S | outdoors | · Falling dust, wind dust · Rain, sleet, snow · Solid ice (external mechanism remains operable) |
NEMA 4 | Indoor/outdoor | · Falling dust, wind dust · Rain, sleet, snow · Water sprinkling, hose guided water |
NEMA 4X | Indoor/outdoor | · Falling dust, wind dust · Rain, sleet, snow · Water sprinkling, hose guided water · corrosion · Damage caused by external icing |
NEMA 5 | Mainly indoors | · Falling dirt, dust, lint and fiber in the air · Drips and light splashes |
NEMA 6 | Indoor/outdoor | · fallen dust · Hose guide water · Temporary inundation at limited depth · Damage caused by external icing |
NEMA 7 | within four walls | · Internal explosion complies with UL Class I, Groups C&D explosion-proof requirements |
NEMA 8 | Indoor/outdoor | · Combustion meets UL Class I, Groups C&D explosion-proof requirements |
NEMA 9 | within four walls | · Dust ignition meets UL Class II, Groups E, F, G requirements |
NEMA 10 | Indoor/outdoor | · MSHA compliant internal explosion |
NEMA 11 | within four walls | · Dropping corrosive liquid and gas |
NEMA 12 | within four walls | · Falling dirt, circulating dust, lint, fiber · Drips and light splashes |
NEMA 13 | within four walls | · Falling dirt, circulating dust, lint, fiber · Drips and light splashes · Spray, splash and oil leakage · Non corrosive coolant |
Red=hazardous situation
What is an IP rating?
The IP (ingress protection) rating is based on the IEC 60529 international standard, using a two digit system. The first number represents the protection against various solid intrusions, ranging from 0 (no protection at all) to 6. The second number represents the protection against various liquid intrusions, using a similar ranking, but reaching 9K. For example, most umbrellas are IP01:0=not resistant to solids, 1=resistant to vertical drops of water.
IP is the preferred encoding system in the EU, but it is also increasingly used in the United States and other countries. The following table lists the IP class codes and their general allowable conditions:
IP rating code
First digit: protection of solids | Second digit: liquid protection |
|---|
0 | No protection | 0 | No protection |
1 | Objects>50 mm (2 in) For example, hands, larger animals | 1 | Droplets, falling vertically |
2 | Objects>12 mm (. 5 in) For example, fingers, smaller animals | 2 | Spray water at 15 ° from vertical |
3 | Objects>2.5 mm (. 01 in) For example, thick wires, tools, insects | 3 | Water spray,<60 ° from vertical |
4 | Objects>1 mm (0.04 in) For example, thin lines | 4 | Drops and spray, any direction Limited access allowed |
5 | dustproof Limited access allowed | 5 | Water jet and spray, low pressure Limited access allowed |
6 | Dustproof | 6 | Water jet, high pressure For example, strong jets, waves, rough seas |
| | 7 | Immerse in water for a limited duration According to the specified pressure and time conditions |
| | 8 | Immerse in water indefinitely At the specified pressure |
| | 9K | Steam injection, high temperature and high pressure K = according to ISO 20653 |
Here are some items and their IP ratings:
● Chain fence: IP10
● Shredded chicken: IP20
● Window screen: IP30
● Kevlab: IP40
● Camping tent: IP42
● Fresh film: IP51
● Wine bottle: IP67
● The latest generation of smart phones: IP68
