The Ingress Protection (IP) rating of a motor shows how well it protects against both water and solid foreign objects such as dust.
Usually found on the motor nameplate, this information is crucial when choosing an electric motor as it ensures that the enclosure can protect the motor from the environment it is operating in.
IP ratings are defined in standards set by the International Electrotechnical Commission (IEC), whereas The National Electrical Manufacturers Association (NEMA) uses an enclosure description of a similar standard.
In this blog post, we take a look at IP ratings, what they mean and how to understand the IP rating of your motor.
IP or Ingress Protection refers to the degree of protection that enclosed equipment has from both foreign objects and moisture.
The first digit of the IP rating which goes from 0 to 6 refers to the protection the enclosure offers from solid foreign objects. The highest level of protection means that the motor is completely protected against dust.
As well as motor performance, this is a safety factor that can protect against accidental contact with the motor with tools, wires or parts of the body.
The second digit of the IP rating which goes from 0 – 9 refers to the protection the enclosure offers from moisture. The highest level of protection here means that the motor is protected against high-pressure and high-temperature jets of water.
As well as motors, IP ratings can be used to grade the resistance of an enclosure against dust and liquids for devices such as heating units, fans and power supply cases.
An IP rating is a combination of two numbers that indicate how well protected the enclosure is against water and foreign objects. Use the table below to see how well protected your motor is.
| Solid Foreign Objects | Water |
| 0 – No protection | 0 – No protection |
| 1 – Protected against solid foreign objects of 50 mm and greater | 1 – Protected against vertically falling drops |
| 2 – Protected against solid foreign objects of 12,5 mm and greater | 2 – Protected against vertically falling water drops when enclosure tilted up to 15° |
| 3 – Protected against solid foreign objects of 2,5 mm and greater | 3 – Protected against spraying water |
| 4 – Protected against solid foreign objects of 1,0 mm and greater | 4 – Protected against splashing water |
| 5 – Dust-protected | 5 – Protected against water jets |
| 6 – Dust-tight | 6 – Protected against powerful jets |
| 7 – Protected against the effects of temporary immersion in water | |
| 8 – Protected against the effects of continuous immersion in water | |
| 9 – Protected against high pressure and temperature water jets |
In the example below, IP55 would indicate that the motor is protected against dust whilst also being protected against water jets.
To find out more about the information that can be found on the nameplate of a motor, take a look at our blog post on how to read a motor nameplate.
Equipment should protect against external influences that could negatively impact the equipment, user or environment and so the recommended IP rating of your motor will depend on these factors.
In the most demanding environments which are potentially explosive such as quarries, sewage treatment plants or oil rigs; a higher degree of protection will be required.
Failing to take these considerations into account can result in damage to the motor, injury or even complete failure of the motor if the IP rating does not offer an adequate level of protection.
Whatever industry you work in, it’s essential to ensure that the IP rating offered by your motor takes into consideration the risk of impact from liquids and solid foreign objects.
At Mawdsleys, we are experts in the supply, installation, and ongoing maintenance of rotating equipment including AC motors, DC motors and generators.
To find out more about how we can help you, give one of our expert team a call today on 0117 955 2481 or fill out the form below and we will get back to you.
