The two digits after the IP indicate the protection strength of the device enclosure against solid foreign objects and water intrusion. The first number indicates the level of the electrical equipment against dust and foreign objects intrusion, and the second number indicates the equipment’s resistance to moisture and water intrusion. The degree of airtightness, the larger the number, the higher the protection level.
For example: IP54 protection grade, IP is the marked letter, the number 5 is the first marked number, 4 is the second marked number. The first marked number indicates the level of contact protection and foreign object protection, and the second marked number indicates the waterproof protection level.
In addition, when the level of protection requirements is higher than the level indicated by the above characteristic numbers, the extended range will be expressed by adding an appendix letter after the first 2 digits, which also needs to meet the respective requirements of these additional letters.