Industrial computers are designed to protect against harmful elements from penetrating the enclosure to the computer and damaging the system. To help consumers select the right industrial PC with the correct computer enclosure, rating systems have been designed by both Europe and USA.
Guide to IP Ratings
The European system, known as ingress protection (IP), defines two numbers for an enclosure. The first number denotes the protection against solid objects whilst the second digit demonstrates the protection offered against liquids. Each number defines the protection offered with the higher the number the better protection that is offered. So therefore and IP65 enclosure offers both better dust proofing and waterproofing than an IP54 enclosure.
First Digit (solid object protection)
0 No special protection offered
1 Protection from solid objects greater than 50mm in diameter.
2 Protection against fingers or other object not greater than 80mm in length and 12mm in diameter.
3 Protection from entry by tools, wires etc, with a diameter of 2.5 mm or more.
4 Protection against solid bodies larger than 1mm
5 Protected against dust that may harm equipment.
6 Totally dust tight.
Second Digit (moisture protection)
0 No protection offered.
1 Protection against condensation.
2 Protection against droplets deflected up to 15° from vertical
3 Protected against spray up to 60° from vertical.
4 Protected against water spray from all directions.
5 Protection against low pressure water jets (all directions)
6 Protection against high pressure water jets and waves.
7 Protected against temporary immersion.
8 Protected against prolonged effects of immersion
The NEMA standard is devised by the USA’s National Electrical Manufacturers Association (NEMA) and is similar to the European system although only a single digit is used.
NEMA 1 – protection against falling dirt and large objects such as fingers
NEMA 2 – Same as NEMA 1 including protection against light splashing of liquids.
NEMA 3 – Enclosures that provide a degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and that will be undamaged by the external formation of ice on the enclosure.
NEMA 3R – Same as NEMA 3 excluding protection against windblown dust.
NEMA 3S – Enclosures provide a degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and in which the external mechanism(s) remain operable when ice laden.
NEMA 4 – Protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water; and that will be undamaged by the external formation of ice on the enclosure.
NEMA 4X – Same as NEMA 4 including protection against corrosion.
NEMA 5 – Enclosures protection against falling dirt; against settling airborne dust, lint, fibers, and flyings; and to provide a degree of protection against dripping and light splashing of liquids.
NEMA 6 – Enclosures protection against falling dirt; against hose-directed water and the entry of water during occasional temporary submersion at a limited depth; and that will be undamaged by the external formation of ice on the enclosure.
NEMA 6P – Same as NEMA 6 including protection against the entry of water during prolonged submersion at a limited depth.
NEMA 7 – Enclosures are for indoor use in locations classified as Class I, Groups A, B, C, or D and shall be capable of withstanding the pressures resulting from an internal explosion of specified gases,
NEMA 9 – Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting or discoloring dust on the enclosure or igniting dust-air mixtures in the surrounding atmosphere.
NEMA 12 – Enclosures protection against falling dirt; against circulating dust, lint, fibers, and flyings; and against dripping and light splashing of liquids.
NEMA 12K – Same as NEMA 12 including enclosures constructed with knockouts.
NEMA 13 – Enclosures protection against falling dirt; against circulating dust, lint, fibers, and flyings; and against the spraying, splashing, and seepage of water, oil, and non-corrosive coolants.
Information courtesy of IEC, NEMA and CENELEC