Page 29 - Electrical Safety of Low Voltage Systems

12 Chapter Tw o

6) indicates the degree of protection against access of person’s finger/
back of hand to hazardous parts as well as against ingress of solid
foreign objects. The second numeral (0 to 8) designates the degree of
protection against ingress of water through enclosures and barriers.
An optional letter (A to D) designates, just like the first numeral, the
degree of protection against direct contact. A brief description of the
characteristic numerals and optional letters can be found in Fig. 2.3.

Protection of Equipment Against Person’s
1st Numeral Against Solid Particles Access With
0 Nonprotected Nonprotected
1 > 50 mm diam. Back of hand
2 > 12.5 mm diam. Finger
3 > 2.5 mm diam. Tool
4 > 1 mm diam. Wire
5 Dust Wire
6 Dust proof Wire

2nd Numeral Protection of Equipment Against Ingress of Water
0 Nonprotected
1 Vertical dripping
2 Dripping (15° tilted)
3 Rain (spraying water at an angle up to 60° on
either side of the vertical)
4 Splashes from any direction
5 Jets from any direction
6 Powerful jets from any direction (flow rate
3
> 12.5 dm /min)
7 Temporary immersion
8 Continuous immersion

Optional Letter Protection Against Person’s Access With
A Back of hand
B Finger
C Tool
D Wire

FIGURE 2.3 Brief description of the IP designations.