GB/T 4208-2017Degrees of protection provided by enclosures (IP code) (English PDF)

1 Scope

The standard applies to the classification of degrees of protection provided by enclosures for electrical equipment with a rated voltage not exceeding 72.5 kV.

Its stated purposes are to define, for electrical equipment, the degrees of protection of the enclosure against access of persons to hazardous parts inside it, against ingress of solid foreign objects and against ingress of water having harmful effects on the equipment; to define the designation of those degrees; to state the requirements for each designation; and to verify enclosures by test against the requirements of the standard.

The extent and the manner in which product standards call up degrees of protection, and which enclosure is adopted, are left to the product standard; the tests used for a given degree shall comply with the standard, and supplementary requirements may be added in the relevant product standard where necessary. Details that may be specified in a product standard are given in Annex B.

For equipment of a special type, a product standard may lay down different requirements provided that at least the same level of safety is assured. The standard considers only enclosures that comply in all respects with the relevant product standard and whose material and workmanship, under normal conditions of use, ensure the intended degree of protection. It also applies to the empty enclosure of a type of equipment when that type satisfies the general test requirements and the selected degree of protection is suitable for it.

Protective measures against mechanical damage, corrosion, corrosive solvents such as cutting fluids, mould, vermin, solar radiation, icing, moisture from condensation and explosive atmospheres, and protection against contact with hazardous moving parts outside the enclosure such as fans, are laid down in the relevant product standards. Barriers not connected to the enclosure and obstacles provided solely for personal safety are not regarded as part of the enclosure and are not dealt with in the standard.

2 Normative references

The documents cited are GB/T 2421.1-2008 on environmental testing of electric and electronic products, general and guidance; GB/T 2423.37-2006, environmental testing, test L, dust and sand test; IEC 60050-195:1998, International Electrotechnical Vocabulary, Part 195, earthing and protection against electric shock; IEC 60050(826):1982, chapter 826 on electrical installations of buildings; and IEC 60071-2:1996, insulation co-ordination, Part 2, application guide.

3 Terms and definitions

3.1 enclosure: part of equipment that protects the equipment against certain external influences and, in any direction, prevents direct contact. A note explains that within the scope of the standard the definition taken from the International Electrotechnical Vocabulary is read as follows: enclosures provide protection of persons or of livestock against access to hazardous parts inside; and barriers, shapes of openings or any other means, whether attached to the enclosure or formed by the enclosed equipment, that prevent or limit the entry of the specified test probes are regarded as part of the enclosure, except where they can be removed without the use of a key or a tool.

3.2 direct contact: contact of persons or livestock with live parts. The note records that, on the basis of the vocabulary definition, the term direct contact is replaced in the standard by access to hazardous parts.

3.3 degree of protection: extent of protection provided by an enclosure against access to hazardous parts, against ingress of solid foreign objects and against ingress of water, verified by the test methods laid down in the standard.

3.4 IP code: coding system that indicates the degrees of protection of the enclosure against access to hazardous parts, against ingress of solid foreign objects and against ingress of water, and that gives additional information connected with such protection.

3.5 hazardous part: part that is hazardous to approach or to touch. 3.5.1 hazardous live part: live part that, under certain conditions, can give a harmful electric shock. 3.5.2 hazardous mechanical part: moving part that is hazardous to touch, other than a smooth rotating shaft.

3.6 protection provided by an enclosure against access to hazardous parts: protection of persons against contact with hazardous low-voltage live parts, against contact with hazardous mechanical parts, and against approach to hazardous high-voltage live parts where the space inside the enclosure is insufficient. A note adds that such protection may be afforded by the enclosure itself, or by a barrier forming part of the enclosure, or by a distance inside the enclosure.

3.7 adequate clearance for protection against access to hazardous parts: distance that prevents the access probe from touching or approaching a hazardous part.

3.8 access probe: test tool that conveniently simulates a part of the human body, or a tool or the like, and that is held in the hand to verify whether the clearance from a hazardous part is adequate.

3.9 object probe: test tool that simulates a solid foreign object in order to verify the possibility of its ingress into the enclosure.

3.10 opening: hole or gap that exists in the enclosure itself or is formed by applying the specified force with a test probe.

4 Designation

4.1 Arrangement of the IP code. The degree of protection provided by an enclosure is expressed by the letters IP followed by the first characteristic numeral, which is a digit from 0 to 6 or a letter; the second characteristic numeral, which is a digit from 0 to 9 or a letter; an optional additional letter A, B, C or D; and an optional supplementary letter H, M, S or W. Where a characteristic numeral is not required to be specified it is replaced by the letter X, and if both numerals are omitted the code is written XX. The additional letter or the supplementary letter, or both, may simply be omitted without replacement. When more than one supplementary letter is used they are placed in alphabetical order. Where an enclosure provides different degrees of protection according to different mounting arrangements, the manufacturer shall state the degree of protection in the instructions for the mounting arrangement concerned. The way in which the enclosure is marked is dealt with in Clause 10.

4.2 Elements of the IP code and their meanings. The table in 4.2 sets out, for each element of the code, the digit or letter used, the meaning for the protection of the equipment, the meaning for the protection of persons and the clause to be consulted. For the first characteristic numeral, which is dealt with in Clause 5, the protection of the equipment against ingress of solid foreign objects runs from no protection at 0 through objects of diameter 50 mm and greater at 1, 12.5 mm and greater at 2, 2.5 mm and greater at 3 and 1.0 mm and greater at 4, to dust-protected at 5 and dust-tight at 6; the corresponding protection of persons against access to hazardous parts runs from no protection to the back of the hand, the finger, a tool and, from 4 to 6, a wire. For the second characteristic numeral, dealt with in Clause 6, the protection against harmful effects of the ingress of water runs from no protection at 0 through vertically falling drops at 1, drops falling at 15° at 2, spraying water at 3, splashing water at 4, water jets at 5, powerful water jets at 6, temporary immersion at 7, continuous immersion at 8 and high-temperature, high-pressure water jets at 9. The optional additional letters A, B, C and D, dealt with in Clause 7, denote protection of persons against access to hazardous parts with the back of the hand, a finger, a tool and a wire respectively. The optional supplementary letters, dealt with in Clause 8, carry information specific to the apparatus: H for high-voltage apparatus, M where the specimen is running during the water test, S where the specimen is stationary during the water test, and W for weather conditions.

4.3 Examples of the use of the IP code. The examples given are IP44 with neither additional nor optional letter; IPX5 with the first characteristic numeral omitted; IP2X with the second characteristic numeral omitted; IP20C using an additional letter; IPXXC with both characteristic numerals omitted and an additional letter used; IPX1C with the first characteristic numeral omitted and an additional letter used; IP3XD with the second characteristic numeral omitted and an additional letter used; IP23S using a supplementary letter; IP21CM using both an additional and a supplementary letter; and IPX5/IPX7/IPX9, a triple marking on the enclosure indicating that the requirements for protection against water jets, against temporary immersion and against high-temperature, high-pressure water jets are all satisfied. Further examples are given in Clause 9.

5 Degrees of protection indicated by the first characteristic numeral

The first characteristic numeral marked on the enclosure indicates that both the condition of 5.1 and the condition of 5.2 are satisfied: the enclosure protects persons by preventing a part of the body or an object held in the hand from approaching a hazardous part, and protects the equipment by preventing the ingress of solid foreign objects. Where an enclosure also complies with every degree lower than a given one, only that degree is marked with its numeral, and where a test is clearly applicable to any lower degree of protection, the tests for the lower degrees need not be carried out.

5.1 Protection against access to hazardous parts. Table 1 gives the brief description and the meaning of each degree, states that the degree is fixed by the first characteristic numeral alone and that the brief description and the meaning are not to be taken as the specification of the degree, and refers to Clause 12 for the tests. Numeral 0 means no protection. Numeral 1 means protection against access with the back of the hand, and requires that a sphere probe of diameter 50 mm keep an adequate clearance from the hazardous part. Numeral 2 means protection against access with a finger, and requires that a jointed test finger of diameter 12 mm and length 80 mm keep an adequate clearance from the hazardous part. Numeral 3 means protection against access with a tool, and requires that a probe of diameter 2.5 mm not enter the enclosure. Numerals 4, 5 and 6 mean protection against access with a wire and require that a probe of diameter 1.0 mm not enter the enclosure. The test conditions column refers to 12.2 for numerals 1 to 6. A note adds that for numerals 3, 4, 5 and 6 the requirement is regarded as met if the probe keeps an adequate clearance from the hazardous part inside the enclosure, the adequate clearance being laid down by the product standard committee in accordance with 12.3, and that because the requirements of Table 2 are met at the same time, Table 1 states that the probe shall not enter.

5.2 Protection against ingress of solid foreign objects. Table 2 gives the brief description and the meaning of each degree and refers to Clause 13 for the tests. Where the first characteristic numeral is 1 or 2 the object probe shall not enter the enclosure completely, which means that the full diameter of the sphere shall not pass through an opening of the enclosure; where it is 3 or 4 the object probe shall not enter the enclosure at all. Numeral 0 means no protection; numeral 1 protection against solid foreign objects of diameter 50 mm and greater, verified with a sphere probe of diameter 50 mm; numeral 2 protection against objects of diameter 12.5 mm and greater, verified with a sphere probe of diameter 12.5 mm; numeral 3 protection against objects of diameter 2.5 mm and greater; and numeral 4 protection against objects of diameter 1.0 mm and greater. A dust-protected enclosure marked 5 does not prevent the ingress of dust entirely, but the quantity of dust that enters shall not affect the normal running of the equipment nor impair safety; the test conditions refer to 13.4 and 13.5. A dust-tight enclosure marked 6 admits no dust at all, with test conditions in 13.4 and 13.6. A footnote to the table states that the diametral portion of the object probe shall not enter the opening of the enclosure, and a note observes that where the first characteristic numeral is 1 to 4 an object whose dimensions in the three perpendicular directions exceed the corresponding figure in the third column of Table 2 cannot enter the enclosure, whether the object is regular or irregular in shape.

6 Degrees of protection indicated by the second characteristic numeral

The second characteristic numeral indicates the degree of protection of the enclosure against harmful effects on the equipment caused by the ingress of water.

The tests for the second characteristic numeral are carried out with clean water. If the cleaning operation uses water jets hotter or at a higher pressure than required for numeral 9, or uses solvents, the actual degree of protection may be affected.

Table 3 gives the brief description and the meaning of the degrees represented by the second characteristic numeral; the brief description and the meaning are not to be taken as the specification of the degree, and the tests are given in Clause 14.

For the second characteristic numeral 6 and for the degrees below 6, the degree marked also indicates compliance with the requirements of every lower degree; accordingly, where a test is clearly applicable to all the lower degrees, the tests for those lower degrees need not be carried out.

An enclosure marked with the second characteristic numeral 9 alone has been considered only for suitability against high-temperature, high-pressure water jets, and need not comply with the requirements for the numerals 5, 6, 7 or 8, which cover water jets and immersion, unless it carries the multiple marking shown in the standard.

7 Changes from the previous edition

The foreword records that the standard replaces GB/T 4208-2008 and that, apart from editorial changes, the main technical changes are the following: the second characteristic numeral 9 has been added to the arrangement of the IP code in 4.1; the meaning of the second characteristic numeral 9 has been added in 4.2; an example of the triple marking IPX5/IPX7/IPX9 has been added in 4.3; the field of application for second characteristic numerals higher than 6 has been revised in Clause 6; the water test method and the main test conditions for the second characteristic numeral 9 have been added to Table 8; the water spray test for the second characteristic numeral 9 has been added in 14.2.9; Figures 7 to 12 have been added, covering the dimensions of the fan-shaped nozzle, the dimensions of the nozzle orifice used for verification, examples of fan-shaped nozzles for surfaces of different smoothness, the apparatus for measuring the impact force of the water jet in the IPX9 high-temperature and high-pressure water test, the distribution of the impact force, and the verification of the IPX9 degree of protection on small enclosures against high-temperature and high-pressure water; and B.25 has been added to Annex B.

The standard is the identical adoption, by the translation method, of IEC 60529:2013 in its English version.

The foreword also records the previous editions of the standard it replaces: GB 4208-1984, GB 4208-1993 and GB/T 4208-2008.

The introduction adds that the present revision only introduces the degree of protection given by the second characteristic numeral 9 and makes no change to the degrees of protection already laid down in GB/T 4208-2008, so that the existing test methods are unchanged, and that in general an enclosure marked with a given IP code under the previous edition will meet the same degree under the present one.

8 Note on the printed English title

The English title printed on the cover of the document reads Degrees of protection provided by enclosure (IP code), with enclosure in the singular. The wording has been corrected to enclosures in the record above; no other word of the printed title has been altered.