What Is an IP Rating?

IP stands for "Ingress Protection". In layman's terms, an IP rating measures resistance of a product to dust and water. These ratings are defined in international standard EN 60529 (British BS EN 60529: 1992, European IEC 60509: 1989). They are used to define levels of sealing effectiveness of electrical enclosures against intrusion from foreign bodies (tools, dirt, etc.) and moisture. 

What Do the Digits in an IP Rating Indicate?

The numbers included in an IP rating each have a specific meaning. The first digit is indicative of the degree of protection to people from moving parts and the protection of the equipment inside the unit from foreign bodies. The second digit indicates the product's level of protection against various forms of moisture (droplets, jet spray, immersion, etc.). See the tables below for each digit defined.

Protected Against Solid Objects

1st Number Definition
0 Not Protected
1 Protected against solid objects of over 50 mm in size (for instance, hands)
2 Protected against solid objects of over 12 mm in size (for instance, fingers)
3 Protected against solid objects of over 2.5 mm in size (for instance, tools and wires)
4 Protected against solid objects of over 1 mm in size (for instance, small tools and wires)
5 Protected against limited ingress of dust that will not penetrate in a quantity to interfere with satisfactory operation
6 Protected against any dust ingress

Protected Against Liquids

2nd Number Definition
0 Not Protected
1 Protected against vertically falling drops of water
2 Protected against direct sprays of water when tilted at any angle up to 15° on either side
3 Protected against water sprayed at an angle of 60° on either side
4 Protected against water splashed from any direction
5 Protected against low pressure jets of water from all directions
6 Protected against powerful jets of water from any direction
7 Protected against the effects of temporary immersion in water under standardized conditions and pressure
8 Protected against long periods of submersion in water more severe than 7
9 Protected against water projected at high pressure and temperatures from any direction