IP ratings or Ingress protection ratings are used to indicate the resistance of the product to either Water, dust or mechanical impact. Published by the by the International Electrotechnical Commission (IEC) IP ratings are an attempt to standardise the terms used to describe a product. Terms such as Waterproof, splashproof, rugged and outdoors, are all used to described a range of products . The IP rating refers to a specific series of tests and standards the unit should achieve to obtain a rating.
The first digit is the protection against dust, the most common values are 5 – dust proof and 6 dust tight. For a dust proof system the ingress of dust is not entirely prevented, however it must not enter in sufficient quantity to interfere with operation of the equipment; the unit should offer complete protection against contact with dust. For a dust tight system there should be no ingress of dust and complete protection against contact with dust.
The second digit relates to the ingress of water, here there are 4 common values:
4 : Protection against splashing water
6: Protection against powerful water jets from any angle
7: Immersion up to 1m in water for up to 30 minutes
8: Continuous immersion beyond 1m, typically 3m
The third digit refers to protection against mechanical impact and this is not commonly seen on instrument, for a full explanation of all levels see the following link IP code.
Commonly seen values on instruments are IP54 – splashproof suitable for use in most environments, IP67 and IP68 waterproof to various levels. Example instruments in these classes.