For any lIve parts of class B, they should proVIde the
production of avoiding danger. Protection of directly
contacting with should be provided by dielectric surface of
live parts, or by the out case, or both them.
B. requirements of the way of personnel shock
If the protection is provided by the insulation, the
insulation which will be destroyed only by being apart
cover, should meet the requirements of working voltage
and temperature.
C. requirements of out case
The live parts should be inner of out case, if the
protection supported by case. At the states of normal
working, the protection is strong enough to fight with
extraneous force. They be classified according with the
size of out case and the distance to live parts.
The out case that could be touch directly should meet
the requirement of IPXXD at least. The rest is classified
three kinds as showed in the table:
TABLE 2 SHELL/BLOCK TYPE AND REQUIREMENTS