Connecting the AC Output Power Cable

Precautions

A three-phase AC switch should be installed on the AC side of the inverter. To ensure that the inverter can safely disconnect itself from the power grid when an exception occurs, select a proper overcurrent protection device in compliance with local power distribution regulations.

• Do not connect loads between an inverter and an AC switch that directly connects to the inverter. Otherwise, the switch may trip by mistake.

• If an AC switch is used with specifications beyond local standards, regulations, or the Company's recommendations, the switch may fail to turn off in a timely manner in case of exceptions, causing serious faults.

Each inverter shall be equipped with an AC output switch. Multiple inverters shall not connect to the same AC switch.

The inverter is integrated with a comprehensive residual current detection unit to distinguish fault current from residual current. Upon detecting that the residual current exceeds the threshold, the inverter immediately disconnects from the power grid.

Cable Connection Precautions

• The cable outer diameter can be measured using the ruler sticker in the maintenance compartment.
• Ensure that the cable jacket is in the maintenance compartment.
• Ensure that the AC output power cable is secured. Failing to do so may cause the solar inverter to malfunction or damage to its terminal block by issues such as overheating.

• The ground point on the enclosure is preferred to connect to the PE cable for the inverter.
• The PE point in the maintenance compartment is used for connecting to the PE cable included in the multi-core AC power cable.
• There are two ground points on the chassis shell and you only need either of them.
• It is recommended that the PE cable of the inverter be connected to a nearby ground point. For a system with multiple inverters connected in parallel, connect the ground points of all inverters to ensure equipotential connections to ground cables.

Cable Specifications

• If you connect a ground cable to the ground point on the chassis shell, you are advised to use a three-core (L1, L2, and L3) outdoor cable or three single-core outdoor cables.
• If you connect a ground cable to the ground point in the maintenance compartment, you are advised to use a four-core (L1, L2, L3, and PE) outdoor cable.
• You need to prepare the OT or DT terminal that matches the cable.

Figure 5-8 Specifications of the Crimped OT/DT Terminal

Figure 5-9 Specification of the Rubber Baffle Plate

• The cable diameter must comply with local cable standards. The factors that affect cable selection include the rated current, cable type, routing mode, ambient temperature, and maximum expected line loss.
• When the MBUS is used for communication, it is recommended that the multi-wire cable be used. The maximum communication distance is 1000 m. If other types of AC power cables are used, contact Huawei technical support.

Connecting the PE Cable

1. Secure the PE cable using the ground screw.
   Figure 5-10 Cable connection
   

2. (Optional) Apply silica gel or paint on the ground terminal to protect it against corrosion.

Connecting the AC Output Power Cable (Multi-core)

1. Connect the AC cable to the terminal block.

   Sufficient slack should be provided in the PE cable to ensure that the last cable bearing the force is the PE cable when the AC output power cable bears pulling force due to force majeure.

   Figure 5-11 Cable connection
   

Connecting the AC Output Power Cable (Single-core)

1. Connect the AC cable to the terminal block.
   Figure 5-12 Cable connection
   

The 32–36 mm cable is supported only by some models. Refer to the corresponding label to get the supported size.

Bending Radius

Figure 5-13 Bending Radius

The AC power cable must be routed vertically into the maintenance compartment.