IP #	First Number - Protection against solids	Second Number - Protection against liquids	Third Number - Protection against mechanical impacts (often omitted)
0	No Protection	No Protection	No Protection
1	Protected against solid objects over 50mm	Protected against vertically falling drops of water	Protected against impact of 0.225 joules
2	Protected against solid objects over 12mm	Protected against direct sprays up to 15 deg. from vertical	Protected against impact of 0.375 joules
3	Protected against solid objects over 2.5mm	Protected against direct sprays up to 60 deg. from vertical	Protected against impact of 0.5 joules
4	Protected against solid objects over 1mm	Protected against direct sprays from all directions - limited ingress permitted	Protected against impact of 2.0 joules
5	Protected against dust - limited ingress permitted	Protected against low pressure jets from all directions - limited ingress permitted	Protected against impact of 6.0 joules
6	Totally protected against dust	Protected against strong jets from all directions - limited ingress permitted	Protected against impact of 20.0 joules
7		Protected against effects of immersion from 15cm - 1m
8		Protected against long periods of immersion under pressure
9k		Protected against close-range, high pressure, high temperature spray downs

For example IP65 would be interpreted for protection as follows: 6 (being the first number of the code, the number relates to the second column in the table) - Totally protected against dust, and 5 (being the second number of the code, the number relates to the third column in the table) - Protected against low pressure jets of liquids from all directions - limited ingress permitted.

This system is designed for IP ratings of up to three digits.