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9.2 Requirement to Conform to the Low Voltage Directive
9.2.5 Grounding
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EMC AND LOW VOLTAGE DIRECTIVES
9.2.5 Grounding
There are the following two different grounding terminals.
Use either grounding terminal in an earthed status.
Protective grounding
: Maintains the electrical safety of the PLC and improves the
noise resistance.
Functional grounding
: Improves the noise resistance.
9.2.6 External wiring
(1) 24VDC external power supply
This power supply must include a reinforced insulation for 24VDC circuit to prevent
dangerous voltage for CC-Link Safety remote I/O module.
(2) External devices
When a device with a hazardous voltage circuit is externally connected to the PLC,
use the device whose interface circuit section to the PLC has the reinforced insulation
against the hazardous voltage circuit.
(3) Reinforced insulation
The reinforced insulation covers the withstand voltages shown in Table9.3.
Table9.3 Reinforced Insulation Withstand Voltage
(Installation Category II, source : IEC664)
Rated voltage of hazardous
voltage area
Surge withstand voltage
(1.2/50 s)
150VAC or below
2500V
300VAC or below
4000V