Several Common Ways Of Grounding Garden Lights And Lawn Lights And Several Major Issues That Should Be Paid Attention To

Common ways to protect the grounding of the metal shell of garden lights and lawn lights

The grounding protection method commonly used for courtyard lights and lawn lights in low-voltage power distribution systems is a protection system where the metal shell is directly grounded, which is called protective grounding. The author once cooperated with the Street Light Management Office of the Power Supply Bureau. The street light industry is commonly known as single pole grounding. Also called TT system, I think it can be used for reference. The first symbol "T" indicates that the neutral point of the power system is directly grounded; the second symbol "T" indicates that the street lamp metal pole is directly connected to the earth through the grounding body, and has nothing to do with how the system is grounded. In the I-I’ system, all connections of the load

The ground is called protective ground.

2.2 TN mode

Once the housing of garden lights and lawn lights is electrified, the zero protection system can increase the leakage current to short-circuit current. This current is very large. In fact, it is

It is a single phase-to-ground short-circuit fault, the fuse of the fuse will blow, and the trip of the low-voltage circuit breaker will immediately act and trip, which will power off the faulty equipment, which is relatively safe.

Complete.

2.3 TN-C mode

Because the three-phase load of the courtyard lamp and lawn lamp power distribution system is difficult to balance, there is an unbalanced current on the zero line of the work, and there is a voltage to the ground, so it is connected with the protection line

The metal shell of the connected garden lamp and lawn lamp has a certain voltage; if the working device is disconnected, the protection of the garden lamp and lawn lamp shell connected to the zero is charged;

If the phase line of the power supply touches the ground, the potential of the housing of the garden lamp and lawn lamp will rise, which will spread the dangerous potential on the neutral line; used on the trunk line of the TN-C system

When the leakage protector is used, all repeated grounding behind the working zero line must be removed, otherwise the leakage switch cannot be closed, and the working zero line cannot be disconnected under any circumstances. So the neutral line can only be grounded repeatedly

What aspects should be paid attention to when grounding garden lights and lawn lights

In the actual application of TT grounding type garden lights and lawn light power distribution systems, some problems are prone to occur due to various reasons. The existence of these problems will bring unreliable or unsafe hidden dangers to the power distribution of garden lights and lawn light systems. According to Experience reminds peers that the N wire cannot be repeatedly grounded by human error, or the N wire is connected to the lamp pole due to damage to the insulation of the N wire, which causes the N wire to be connected to the separate grounding body of the lamp pole at a lamp pole, so that the N wire is repeatedly grounded. In this case , After the neutral line is repeatedly grounded, part of the normal load current will flow through the earth, forming a leakage current to the leakage protection circuit breaker and causing it to malfunction, causing the system to be unreliable. Therefore, it is necessary to recognize whether the grounding system is of the "I-I" type or the TN type, and the N line of the TT system must not be artificially grounded. On the other hand, it is necessary to ensure that the neutral wire has sufficient mechanical strength and insulation capacity. The N wire should have the same cross-section and insulation level as the phase wire, so that the N wire is not easy to be damaged and grounded.