Protection classes state, according to IEC 34-5, how the motor is protected against contact and water. These are stated with the letters IP and two digits. The first states the protection against contact and penetration by a solid object. The other digit states the protection against water.

For example

IP23 represents:

(2) protect against solid objects greater than 12 mm,
(3) protect against direct sprays of water up to 60° from the vertical.

IP54 represents:

(5) protection against dust,
(4) protection against water sprayed from all directions.

IP55 represents:

(5) protection against dust,
(5) protection against low-pressure jets of water from all directions.