Ingress Protection express the degree of which enclosure protects the inside equipment.
Ingress Protection is specified by “IP” appended by two digits which represent the enclosure ability to prevent the ingress of dusts and liquids.
The first digit indicates the degree of protection of enclosure against the ingress of solid particle. It is also usually used to designate the protection of enclosure against personnel contact with the equipment either live or rotating.
The second digit indicates the degree of protection of enclosure against the ingress of water.
IEC 60529 is international standard which describes details for degree of protection provided by enclosures.