Power Supply - Mitsubishi A1SJH(S8) User Manual

9. EMC AND LOW VOLTAGE DIRECTIVES
9.2.3

Power supply

The insulation specification of the power supply module was designed assuming
installation category II. Be sure to use the installation category II power supply to the
programmable controller.
The installation category indicates the durability level against surge voltage generated by
a thunderbolt. Category I has the lowest durability; category IV has the highest durability.
Category II indicates a power supply whose voltage has been reduced by two or more
levels of isolating transformers from the public power distribution.
Category IV Category III
Figure9.1: Installation Category
9 - 11
Category II Category