External Wiring - Mitsubishi A-Melsec A1FXCPU User Manual

5. EMC DIRECTIVE, LOW VOLTAGE DIRECTIVE

5.2.5 External wiring

(1) 24VDC external supply power
A 24VDC I/O module or a special module requiring external supply power should
be the one whose 24VDC circuit is enhanced-insulated from a hazardous voltage
circuit.
(2) Externally connected equipment
External equipment which is connected to the PLC and has a hazardous voltage
circuit inside should be the one whose interface circuit is enhanced-insulated
from the hazardous voltage circuit.
(3) Enhanced insulation
Enhanced insulation indicates the insulation that has the following dielectric
withstand voltage.
Enhanced Dielectric Strength (Installation category II, cited from IEC664)
Rated Voltage of Hazardous Voltage Section
150VAC or less
300VAC or less
Surge Voltage Resistance
5 - 8
MELSEC-A
2500V
4000V