IEC 529 Protection Grades

IEC ( International Electrotechnical Commission )

The IEC has established an enclosure grading system that produces an IP rating. (For example, IP 54 - "5" is the first character - refer to tables I & II. "4" is the second character - refer to table III - following page).

Table I - Degrees of Protection against Hazardous Parts
(Degree of protection is indicated by the first characteristic numeral)
Number Brief Description Definition
0 Non Protected xxx
1 Protected against access to hazardous
parts with the back of a hand.
The access probe, sphere of 50 mm ø, shall have adequate clearance from hazardous parts.
2 Protected against access to hazardous
parts with a finger.
The jointed test finger of 12mm ø, 80 mm length, shall have adequate clearance from hazardous parts.
3 Protected against access to hazardous
parts with a tool.
The access probe of 2.5 mm ø shall not penetrate.
4 Protected against access to hazardous
parts with a wire.
The access probe of 1.0 mm ø shall not penetrate.
5 Protected against access to hazardous
parts with a wire.
The access probe of 1.0 mm ø shall not penetrate.
6 Protected against access to hazardous
parts with a wire.
The access probe of 1.0 mm ø shall not penetrate.

Note: In the case of the first characteristic numerals 3, 4, 5 and 6, protection against access to hazardous parts is satisfied if adequate clearance is kept. Due to the simultaneous requirement specified in Table II the definition "shall not penetrate" is given in Table I.

Table II - Degree of Protection against Solid Foreign Objects
(Degree of protection is indicated by the first characteristic numeral)
Number Brief Description Definition
0 Non Protected  xxx
1 Protected against solid foreign objects of
50 mm ø and greater.
The object probe, sphere of 50 mm ø, shall not fully penetrate.¹
2 Protected against solid foreign objects of
12.5 mm ø and greater.
The object probe, sphere of 12.5 mm ø, shall not fully penetrate.¹
3 Protected against solid foreign objects of
2.5 mm ø and greater.
The object probe of 2.5 mm ø shall not penetrate at all.¹
4 Protected against solid foreign objects of
1.0 mm ø and greater.
The object probe of 1.0 mm ø shall not penetrate at all.¹
5 Dust-protected Ingress of dust is not totally prevented, but dust shall not penetrate in a quantity to interfere with satisfactory operation of the apparatus or to impair safety.
6 Dust-tight No ingress of dust
Table III - Degrees of Protection against Water
(Degree of protection is indicated by the second characteristic numeral)
Number Brief Description Definition
0 Non Protected  xxx
1 Protected against vertically falling water drops Vertically falling drops shall have no harmful effects.
2 Protected against vertically falling water drops when enclosure tilted up to 15°. Vertically falling drops shall have no harmful effects when the enclosure is tilted at any angle up to 15° on either side of the vertical.
3 Protected against spraying water Water sprayed at any angle up to 60° on either side of the vertical shall have no harmful effects.
4 Protected against splashing water Water splashed against the enclosure from any direction shall have no harmful effects.
5 Protected against water jets Water projected in jets against the enclosure from any direction shall have no harmful effects.
6 Protected against powerful water jets Water projected in powerful jets against the enclosure from any direction shall have no harmful effects.
7 Protected against the effects of temporary immersion in water. Ingress of water in quantities causing harmful effects shall not be possible when the enclosure is temporarily immersed in water under standardized conditions of pressure and time.
8 Protected against the effects of continuous immersion in water. Ingress of water in quantities causing harmful effects shall not be possible when the enclosure is continuously immersed in water under conditions which shall be agreed between manufacturer and user but which are more severe than for numeral 7.