Answer / pswin

IP means Index of Protection. All electrical equipments have the degree of protection. First numeral shows (a) Protection of persons against contact with live or moving parts inside enclosure. (b) Protection of equipment against ingress of solid bodies. Second numeral shows protection of equipment against ingress of water. IP 55 means-(a) complete protection against contact,(b) dustproof and jet(water projected from a nozzel) proof. For IP 65, for second numeral 5 is same above and for first numeral 6 shows that it is a dust tight equipment. The greater digit shows the higher protection.

Answer / u.chandarasekar

pl refer to dinamalar and siruvar malar book

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