Definition of Protection Grades IEC 60529

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

First
Characteristic
Numeral
Brief Description Definition
0 Non Protected  
1 Protected against access to hazardous parts with theback 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 - Degrees of Protection against Solid Foreign Objects

Degree of protection is indicated by the first characteristic numeral

First
Characteristic
Numeral
Brief Description Definition
0 Non Protected  
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 atisfactory operation of the apparatus or to impair safety.
6 Dust-tight No ingress of dust

¹ The full diameter ot the object probe shall not pass through an opening of the enclosure.  

Table III - Degrees of Protection against Water

Degree of protection is indicated by the second characteristic numeral

First
Characteristic
Numeral
Brief Description Definition
0 Non Protected  
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.

NEMA to IEC

Enclosure Rating Cross-Reference¹ 
(CANNOT be used to convert IEC Classification designations to NEMA Type Ratings)

NEMA Type IP20 IP22 IP24 IP54 IP55 IP66 IP67
1            
2            
3            
3R            
4            
4X            
6            
12, 12K            
13            

¹ This cross reference is an approximation of NEMA and IEC classifications for reference only. Please consult the appropriate agencies for requirements and test qualifications for complete information.