The IP rating system classifies the protection of emergency lights and exit signs from dust, water and impact afforded by electrical equipment and their enclosures.
The system is recognised in most European countries and is set out in IEC529 (BS EN 60529: 1992) Degrees of Protection provided by Enclosures (IP code).
The degree of protection is expressed as 'IP', followed by two numbers which define the degree of protection. The first digit indicates the extent, to which
the equipment is protected against particles, or to which persons are protected from enclosed hazards. The second digit indicates the extent of protection against
water.
IP20
(2) SOLID - Protected against solid objects over 12mm diameter, not exceeding
80mm long, e.g. fingers
(0) LIQUID - Not protected
IP23
(2) SOLID - Protected against solid objects over 12mm diameter, not exceeding
80mm long, e.g. fingers
(3) LIQUID - Protected against sprayed water at up to 60° from the vertical
IP40
(4) SOLID - Protects against solid objects over 1.0mm, e.g. small wires
(0) LIQUID - Not protected
IP43
(4) SOLID - Protects against solid objects over 1.0mm, e.g. small wires
(3) LIQUID - Protected against sprayed water at up to 60° from the vertical
IP44
(4) SOLID - Protects against solid objects over 1.0mm, e.g. small wires
(4) LIQUID - Protected when sprayed from any direction - limited ingress allowed
IP54
(5) SOLID - Protects against dust, limited ingress (no harmful deposit)
(4) LIQUID - Protected when sprayed from any direction - limited ingress allowed
IP55
(5) SOLID - Protects against dust, limited ingress (no harmful deposit)
(5) LIQUID - Protected against low pressure jets, from all directions - limited
ingress allowed
IP64
(6) SOLID - Dust tight. Totally protected against dust
(4) LIQUID - Protected when sprayed from any direction - limited ingress allowed
IP65
(6) SOLID - Dust tight. Totally protected against dust
(5) LIQUID - Protected against low pressure jets, from all directions - limited
ingress allowed