Mitsubishi MELSEC L Series User Manual page 398

(3) Power supply
Power supply modules are designed to meet the overvoltage category II.
Confirm that the power supply to a programmable controller meets the overvoltage category ll.
(4) Control panel
(a) Protection against electric shock
The control panel must be handled as shown below to protect a person who does not have adequate
knowledge of electrical installation form an electric shock.
• Lock the control panel so that only a person who is trained and has acquired enough knowledge of
electrical installation can open the panel.
• Design the control panel so that the power supply is automatically shut off when the panel is opened.
• Use the control panel whose protection degree is IP20 or higher for the purpose of electric shock
protection.
(b) Protection from dust and water
The control panel needs to be dustproof and waterproof.
Insufficient dustproof and waterproof lower the dielectric withstand of the control panel, possibly causing
dielectric breakdown.
The insulation of Mitsubishi programmable controllers is designed to be used in a pollution degree 2
environment. Use them in an environment of pollution degree 2 or below. The pollution degree 2 environment
can be achieved when the programmable controller is installed inside the control panel whose protection
degree is IP54 or equivalent.
(5) Grounding
The following two types of ground terminals are available.
Use the ground terminals in grounded status.
Terminal type
Protective ground
Functional ground
396
Application
Ensures the safety of the programmable controller and
improves the noise resistance.
Improves the noise resistance.