Electrical Enclosure

Fig: Electrical Enclosure-wall mount type



Electrical Enclosures are the essential part of any electrical system. It has mainly two purpose to serve, the one is protecting the user from electrical hazards and the another is to protect the wiring and costly electrical equipment such as breakers, PLC, VFD …are the few in the names from harsh environment and industrial hazards.

Enclosure are the box shaped cabinet in which various electrical equipment are enclosed. Mostly, enclosures are manufacture using steel, stainless steel, aluminum or fiber-glass reinforced polyester. Sheet steel are widely used my industry. To reinforce the protective strength of the cabinet, a rigorous phosphate and powder paint process is followed.

                                  Fig: Console type electrical Enclosure

Types and Ratings

Electrical enclosure can be classified on two major categories based on their dimension and another one is based on its safety standards. In terms of size, enclosures can take the shape of relatively smaller junction boxes, larger wall-mount setups or still larger floor-mount or free-standing enclosures. The choice of the size is determined by the location as well as the equipment that need to be enclosed within include the wire and Bus sizes and number.

To provide a trusted safety standard two bodies are there mostly,

  • Underwriters Laboratories (UL)
  • National Electrical Manufacturers Association (NEMA)

These two bodies have developed a comprehensive enclosure rating scale. The manufacture has to pass the testing in order to get the certificates.

NEMA ratings are the most popular among the two.  Most common electrical enclosure rating is the NEMA Type 1, NEMA Type 3R and NEMA Type 4X. Enclosures of all three ratings provide adequate protection to personnel working near the enclosure. In terms of equipment protection, a NEMA Type 1 enclosure can be only used indoors and is the lowest on the protective scale providing protection from dirt and similar particulate matter.  A NEMA Type 3R enclosure can be used either indoors or outdoors and provides protection from dirt, water (including rain, sleet and snow) and is expected to withstand the formation of ice on the enclosure body. The NEMA Type 4X enclosure is of a higher rating to the Type 3R; it incrementally provides greater corrosion protection as well as protection against hosed directed water.

The safety of Electrical Enclosures are mentioned in terms of IP ratings.

What is IP ratings?

IP rating is also known as Ingress Protection or International Protection ratings are defined to the international standard of EN 60529 (British BS EN 60529:1992). This standard is used to define the levels of sealing effectiveness of electrical enclosures against intrusion from foreign bodies such as tools, dirt and moisture

What do the two digits in an IP Rating mean?

The rating consists of the letters IP followed by two digits, the higher the number the better the protection.  Sometimes a number is replaced by X, which indicates that the enclosure is not rated for that specification. 

IP65   =  First Digit – Solids

The first digit indicates the level of protection that the enclosure provides against the ingress of solid foreign objects, from tools or fingers that could be hazardous if they came into contact with electrical conductors or moving parts, to airborne dirt and dust that could damage circuitry.

IP65   =  Second Digit – Liquids

The second digit defines the protection of the equipment inside the enclosure against various forms of moisture (drips, sprays, submersion etc).

First DigitIntrusion ProtectionSecond DigitMoisture Protection
0No protection.0No protection.
1Protected against solid objects over 50mm, e.g. accidental touch by hands.1Protected against vertically falling drops of water, e.g. condensation.
2Protected against solid objects over 12mm, e.g. fingers.2Protected against direct sprays of water up to 150 from the vertical.
3Protected against solid objects over 2.5mm, e.g. tools & wires.3Protected against direct sprays of water up to 600 from the vertical.
4Protected against solid objects over 1mm, e.g. wires & nails.4Protected against water splashed from all directions, limited ingress permitted.
5Protected against dust limited ingress, no harmful deposits.5Protected against low pressure jets of water from all directions, limited ingress permitted.
6Totally protected against dust.6Protected against strong jets of water, e.g. on ships deck, limited ingress permitted.

             Comparison between NEMA rating IP rating

     The following chart provide comparison between the two types of ratings,

NEMA RatingIP EquivalentNEMA DefinitionProtection Against Solids Protection Against Liquids
1IP10Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment and to provide a degree of protection against falling dirt1 = Protected against solid foreign objects of 50mm in diameter and greater0 = Not Protected
2IP11Enclosures constructed for indoor used to provide a degree of protection to personnel against incidental contact with the enclosed equipment, to provide a degree of protection against falling dirt, and to provide a degree of protection against dripping and light splashing of liquids1 = Protected against solid foreign objects of 50mm in diameter and greater1 = Protected against vertically falling water drops
3IP54Enclosures constructed for either indoor or outdoor used to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to prove a degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and that will undamaged by external formation of ice on the enclosure5 = Protected against dust – Limited to ingress (no harmful deposit)4 = Protected against water sprayed from all directions – Limited to ingress permitted.
3RIP14Enclosures constructed for either indoor or outdoor used to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, and snow; and that will be undamaged by external formation of ice on the enclosure1 = Protected against solid foreign objects of 50mm in diameter and greater4 = Protected against water sprayed from all directions – Limited to ingress permitted.
3SIP54Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to 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.5 = Protected against dust – Limited to ingress (no harmful deposit)4 = Protected against water sprayed from all directions – Limited to ingress permitted.
4IP66Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of 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 enclosure6 = Totally protected against dust6 = Protected against strong jets of water from all directions – Limited to ingress permitted.
4XIP66Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, hose-directed water, and corrosion; and that will be undamaged by thee external formation of ice on the enclosure6 = Totally protected against dust6 = Protected against strong jets of water from all directions – Limited ingress permitted.
5IP52Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of 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.5 = Protected against dust – Limited ingress (no harmful deposit)2 = Protected against direct sprays of water up to 15° from the vertical.
6IP67Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of 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.6 = Totally protected against dust7 = Protected against the effects of temporary immersion between 15cm and 1m. Duration of test 30 minutes.
6PIP67Enclosures constructed for either indoor or outdoor use to provide a degree of protection to the personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against hose-directed water and the entry of water during prolonged submersion at a limited depth; and that will be undamaged by the external formation of ice on the enclosure6 = Totally protected against dust7 = Protected against the effects of temporary immersion between 15cm and 1m. Duration of test 30 minutes.
12 and 12KIP52Enclosures constructed (without knockouts) for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against circulating dust, lint, fibers, and flying; and against dripping and light splashing of liquids5 = Protected against dust – Limited to ingress (no harmful deposit)2 = Protected against direct sprays of water up to 15° from the vertical.
13IP54Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against circulating dust, lint, fibers, and flyings; and against the spraying, splashing, and seepage of water, oil, and noncorrosive coolants.5 = Protected against dust – Limited to ingress (no harmful deposit)4 = Protected against water sprayed from all directions – Limited to ingress permitted.

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