Mitsubishi Electric MELSEC LJ72GF15-T2-U-HW Safety Manuallines page 60

(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.
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