As far as I know, in real life, some of the electrical applicators don't know much about the problems and requirements of landscape yard lamp grounding, and it is easy to see the problem in actual construction. Now let me answer for you, its concentrated performance is: TN-S system on the repeated grounding problem is N line repeated grounding, or PE repeated grounding is not clear. For landscape courtyard lights, repeated grounding is the repeated grounding of the PE line. The analysis is as follows.

1. If no repeated grounding is carried out, when PE is broken, the system is in an unprotected state of neither zero connection nor grounding. After repeated grounding, the system is in the state of zero-connection protection when PE is normal and grounding protection when PE is broken. The landscape yard lamp with repeated grounding has dual protection function, that is, the protection mode of the TT system is changed from TN-S after PE disconnection (PE disconnection is in front of the repeated grounding).

2. The repeated grounding of PE line can reduce the voltage of the equipment shell to the ground when the phase line is short-circuit. When the phase line is short-circuit, the voltage of the shell to the ground is equal to the voltage between the fault point P and the neutral point of the transformer. Assuming that the phase line is the same as the PE line specification, the equipment enclosure is 110V for the ground. The impedance of PE line is parallel to the repetitive grounding resistance RF: which is in series with the grounding resistance RA. In general, the equivalent impedance from P to the neutral point of the transformer is still close to the impedance of the PE line from P to the neutral point of the transformer because the resistance of the repetitive grounding resistance RF connected in series with the working grounding resistance R is much greater than the impedance of the PE line itself. If the phase line conforms to the PE line specification, the voltage UP between the P and the transformer neutral point is still about 110V, while the equipment shell to the ground voltage UP is only part of the voltage UP between the fault P and the transformer neutral point.

3. When the phase line is broken and the earth is short-circuited, the potential of the PE line increases because of the fault current. When the resistance between the breaking point and the earth is small, the potential of the PE line is likely to exceed the safe voltage. This dangerous voltage is transmitted along the PE line to equipment and other shell, endangering personal safety. After repeated grounding, the equivalent resistance of the parallel connection of the repeated grounding resistance and the power supply T is less than the grounding resistance of the power supply T, so that the grounding resistance at the grounding point of the phase line breaks can share the increased voltage, thus effectively reducing the voltage to the ground of the PE line and reducing the electric shock risk.