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3.2.3 Power supply
The insulation specification of the power 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 III
Category II
Category I
Category IV
Figure 1.: Installation Category
Category II indicates a power supply whose voltage has been reduced by two or
more levels of isolating transformers from the public power distribution.