Ingress Protection Ratings

Commonly referred to as the IP rating the ingress protection number is defined in various national and international standards:
BS 5490:1977IEC 529:1976 Classification of degrees of Protection Provided by Enclosures
BS 5420:1977IEC 144:1963 Specification for degrees of Protection of Enclosures of Switchgear and Control Gear for Voltages up to and Including 1000Vac and 1200Vdc

The IP number consists of two or three digits as described below and indicated the degree of protection provided against solid and particulate materials and liquids. The third digit if specified describes the degree of protection against impacts from solid objects. The British standards do not specify the impact digit.

First Digit Protection against Solid Objects
0 No Protection  
1 Protected against solid objects up to 50mm Accidental touch by hand
2 Protected against solid objects up to 12mm Fingers
3 Protected against solid objects over 2.5mm Tools and wires
4 Protected against solid objects over 1.0mm Tools and small wires
5 Protected against dust
Limited ingress permitted with no harmful deposit
 
6 Totally sealed against dust  

Second Digit Protection against Liquids
0 No Protection  
1 Protected against vertically falling water drops Condensation
2 Protected against direct water spray up to 15o from vertical Rain
3 Protected against direct water spray up to 60o from vertical Driving rain
4 Protected against water sprayed from all directions.
Limited ingress permitted
 
5 Protected against low pressure water jets from all directions.
Limited ingress permitted
 
6 Protected against strong water jets from all directions.
Limited ingress permitted
For use on ship decks
7 Protected against immersion between 0.15m and 1m  
8 Protected against long periods of immersion under pressure  

Third Digit Protection against Mechanical Impacts
0 No Protection  
1 Protected against impact of 0.225J 0.15 kg weight dropped from 0.15m
2 Protected against impact of 0.375J 0.25 kg weight dropped from 0.15m
3 Protected against impact of 0.5J 0.25 kg weight dropped from 0.2m
4 Protected against impact of 2.0J 0.5 kg weight dropped from 0.4m
5 Protected against impact of 6.0J 1.5 kg weight dropped from 0.4m
6 Protected against impact of 20.0J 5.0 kg weight dropped from 0.4m

 

 
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