Electrical Safety

Grounding

• For the equipment that needs to be grounded, install the ground cable first when installing the equipment and remove the ground cable last when removing the equipment.
• Do not damage the ground conductor.
• Do not operate the equipment in the absence of a properly installed ground conductor.
• Ensure that the equipment is connected permanently to the protective ground. Before operating the equipment, check its electrical connection to ensure that it is securely grounded.

General Requirements

Use dedicated insulated tools when performing high-voltage operations.

AC and DC Power

Do not connect or disconnect power cables with power on. Transient contact between the core of the power cable and the conductor will generate electric arcs or sparks, which may cause fire or personal injury.

• If a "high electricity leakage" tag is attached on the equipment, ground the protective ground terminal on the equipment enclosure before connecting the AC power supply; otherwise, electric shock as a result of electricity leakage may occur.
• Before installing or removing a power cable, turn off the power switch.
• Before connecting a power cable, check that the label on the power cable is correct.
• If the equipment has multiple inputs, disconnect all the inputs before operating the equipment.
• A circuit breaker equipped with a residual current device (RCD) is not recommended.
• A damaged power cable must be replaced by the manufacturer, service agent, or professionals to avoid risks.
• High voltage operations and installation of AC-powered facilities must be performed by qualified personnel.

Cabling

• When routing cables, ensure that a distance of at least 30 mm exists between the cables and heat-generating components or areas. This prevents damage to the insulation layer of the cables.
• Do not route cables behind the air intake and exhaust vents of the equipment.
• Ensure that cables meet the VW-1 or ZB flame spread rating requirements or higher.
• Bind cables of the same type together. When routing cables of different types, ensure that they are at least 30 mm away from each other.
• If an AC input power cable is connected to the cabinet from the top, bend the cable in a U shape outside the cabinet and then route it into the cabinet.
• When the temperature is low, violent impact or vibration may damage the plastic cable sheathing. To ensure safety, comply with the following requirements:
  • Cables can be laid or installed only when the temperature is higher than 0°C. Handle cables with caution, especially at a low temperature.
  • Cables stored at subzero temperatures must be stored at room temperature for at least 24 hours before they are laid out.
• Do not perform any improper operations, for example, dropping cables directly from a vehicle.
• When selecting, connecting, and routing cables, follow local safety regulations and rules.

ESD

The static electricity generated by human bodies may damage the electrostatic-sensitive components on boards, for example, the large-scale integrated (LSI) circuits.

• Wear ESD gloves or a well-grounded ESD wrist strap when touching the device or handling boards or application-specific integrated circuits (ASICs).
• When holding a board, hold its edge without touching any components. Do not touch the components with your bare hands.
• Package boards with ESD packaging materials before storing or transporting them.

Figure 1-1 Wearing an ESD wrist strap

Neutral-Ground Voltage

It is recommended that the three-phase loads be equalized and the neutral-ground voltage be kept at less than 2 V to meet power distribution requirements.