IP - Ingress Protection Ratings
Ingress Protection (IP) ratings are developed by the European Committee for Electro Technical Standardization (CENELEC) (described IEC/EN 60529), specify the environmental protection an enclosure provides.

The IP rating normally has two (or three) numbers:

1. Protection from solid objects or materials
2. Protection from liquids
3. Protection against mechanical impacts (commonly omitted)

Example - IP Rating
With the IP rating IP 54, 5 describes the level of protection from solid objects and 4 describes the level of protection from liquids.

IP First number - Protection against solid objects

0	No protection.
1	Protected against solid objects up to 50mm, e.g. accidental touch by hands.
2	Protected against solid objects up to 12mm, e.g. fingers.
3	Protected against solid objects over 2.5mm (tools and wires).
4	Protected against solid objects over 1mm (tools, wire, and small wires).
5	Protected against dust limited ingress (no harmful deposit).
6	Totally protected against dust.

IP Second number - Protection against liquids

0	No protection.
1	Protection against vertically falling drops of water e.g. condensation.
2	Protection against direct sprays of water up to 15o from the vertical.
3	Protected against direct sprays of water up to 60o from the vertical.
4	Protection against water sprayed from all directions o limited ingress permitted.
5	Protected against low pressure jets of water from all directions o limited ingress.
6	Protected against low pressure jets of water, e.g. for use on ship decks - limited ingress permitted.
7	Protected against the effect of immersion between 15cm and 1m.
8	Protects against long periods of immersion under pressure.