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1 Preparing for installation
H3C DG-240-55 industrial power supply is an AC-input and DC-output power supply designed for
industrial Ethernet switches. It can be installed only on a TS-35/7.5 or TS-35/15 DIN rail.
Installation environment
Make sure you install the power supply in a favorable environment.
• Do not expose the power supply to direct sunlight, strong mechanical vibrations, shocks, or
magnetic fields.
• Prevent any liquid, foreign objects, or corrosive gas from entering the power supply.
• Do not place the power supply near water or in a damp place and prevent water or moisture
from entering it.
• Keep the power supply as far away as possible from noise sources.
• Keep the air vents of the power supply open and avoid any blocking.
• To prevent the power supply from overheating, ensure a minimum clearance of 100 mm (3.94 in)
above and below the power supply and 50 mm (1.97 in) at both sides of the power supply. If an
adjacent device is a heating source (such as another power supply), increase the distance
between the two to more than 75 mm (2.95 in).
• To prevent a power cord from causing a fire when an overload occurs, use an AWG16-10 power
cord for the power supply. An AWG16-10 power cord has a maximum diameter of 2.8 mm (0.11
in). As a best practice, strip a maximum of 7 mm (0.28 in) of insulation from the power cord for
connection.
IMPORTANT:
To connect the power supply to a device, make sure the diameter of the power cord meets the
acceptable range allowed by the power port on the device.
Installation guidelines
To avoid bodily injury or damage to the power supply, read the following information carefully before
installing the power supply:
• Only authorized personnel can install and operate the power supply.
• Before installing the power supply, cut off power input and make sure no voltage is present on
the power supply.
• When installing the power supply, avoid any intrusion, such as metal sheets, conductors, clips,
or scissors, into the power supply.
• Do not dissemble, refit, or repair the power supply or touch the inside of the power supply.
• Before connecting power to the power supply, use a multimeter to test whether the live wire,
neutral wire, or PE wire is short-circuited and whether the output end is short-circuited.
• Make sure the input and output terminals are correctly connected.
• When the power supply is operating, do not touch it or any wire or terminal.
• Allow the voltage to disappear before you touch the power supply just powered off. When the
power supply is operating, its internal voltage can reach up to 400 V. Residual voltage remains
30s after the power is cut off.