Supply Power - Mitsubishi Electric MELCEC Q Series User Manual

8. EMC AND LOW VOLTAGE DIRECTIVES
8.2.3

Supply power

The insulation specification of the power supply module is designed assuming installation
category II. Be sure to use the installation category II for supply power to the
programmable controller.
The installation category indicates the durability level against surge voltage generated by
thunderbolt. Category I has the lowest durability; and 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 network.
Category IV Category III
Fig.8.1 Installation category
8 - 13
Category II Category