17 Glossary
100_0000_0005.fm
67
17 Glossary
Class rating
The class rating according to DIN EN 61140 specifies the safety measures for
electrical equipment to avoid electrocution. There are four class ratings:
Class rating
Meaning
0
No special protection apart from the basic insulation.
No grounded conductor.
Plug connection without grounded conductor contact.
I
Connection of all conductive housing components to the
grounded conductor.
Plug connection with grounded conductor contact.
II
Reinforced or double insulation (protective insulation).
No connection to the grounded conductor.
Plug connection without grounded conductor contact.
III
Machines are operated on protective low voltage
(< 50 V).
Connection to the grounded conductor is not necessary.
Plug connection without grounded conductor contact.
