The distribution box is connected with wires. It is required to assemble the switchgear, measuring instruments, protective appliances, and auxiliary equipment in a closed or semi metal cabinet or on a screen to form a low-voltage distribution device. During normal operation, the circuit can be opened or closed through manual or automatic switches.

When there is a malfunction or abnormal operation, use a protective device to cut off the circuit or give an alarm. Measuring instruments can display various parameters during operation, adjust some electrical parameters, prompt or send signals deviating from normal working conditions, and are commonly used in power generation, distribution, and substations.

1. The yellow, green and red (a, b, c) three-phase lines are respectively output from the distribution switch of the general distribution box, the Baby blue working zero line is led out from the working zero line end, and the yellow and green PE protection zero line is led out from the PE end. (Note: The doors and boxes of the main distribution box must be reliably connected with braided soft copper wires, with a protective neutral connection, and a safety distance should be set between the five wires);

2. The yellow, green and red three phase lines of the line are connected to the main disconnector of the secondary distribution box, and the Baby blue N line is connected to the N end of the Residual-current device, and then connected to the working zero breaking terminal board through the leakage protection;

3. Connect green and yellow PE wires to protect the PE board of the zero terminal board;

4. Lead the three-phase line from the main disconnector of the second distribution box to the Residual-current device;

5. Lead out the phase line from the terminal of the Residual-current device to the parallel disconnecting switch; (Note: the PE line cannot enter the Residual-current device, because the action of the line end Residual-current device will trip the primary leakage protection, resulting in a large area of power failure);

6. The yellow, green and red three-phase lines are respectively led out from the shunt disconnector of the distribution box, the Baby blue working zero line is led out from the N-board terminal, and the yellow green double color protection zero line is led out from the PE board terminal; (Note: The reliable connection between the distribution box door and the box must use braided soft copper wire as the protective neutral connection).