Mitsubishi Electric MELSEC-L SSCNETIII/H User Manual page 135

(4) Control panel
(a) Electrical shock prevention
The control panel must be handled as shown below to protect a person who does not have adequate
knowledge of electricity from an electric shock.
• Lock the control panel so that only those who are trained and have acquired enough knowledge of electric
facilities can open the control panel.
• The control panel must have a structure that automatically stops the power supply when the control panel is
opened.
• Use the control panel whose protection degree is IP20 or higher for the purpose of electric shock protection.
(b) Dustproof and waterproof features
The control panel also has the dustproof and waterproof functions.
Insufficient dustproof and waterproof features lower the dielectric withstand voltage, resulting in insulation
destruction.
The insulation in our programmable controllers are designed to cope with the pollution level 2, so use it in an
environment with pollution level 2 or below. The pollution level 2 environments can be achieved when the
programmable controller is stored in a control panel equivalent to IP54.
(5) External wiring
(a) 24VDC external power supply
For the 24VDC I/O modules and intelligent function modules requiring an external power supply, use a 24VDC-
circuit whose insulation is reinforced from the hazardous voltage circuit.
(b) External devices
When a device with hazardous voltage circuit is externally connected to the programmable controller, use a
device whose circuit section of the interface to the programmable controller is intensively insulated from the
hazardous voltage circuit.
(c) Reinforced insulation
The reinforced insulation covers the withstand voltages shown below.
Rated voltage of hazardous voltage area
150VAC or lower
300VAC or lower
(Installation Category II, source: IEC 664)
Surge withstand voltage (1.2/50s)
2500V
4000V
APPENDICES
A
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