The diffuser core, internally installed in the graphite ground wire and connected with the ground wire of protected objects, enables a rapid discharge of incoming electric current to the earth so as to give a rise to a low ground resistance. The mechanism is that it enlarges the diffusing area of the grounding body itself and reduces the contact resistance between the grounding body and soil layers. With strong moisture absorption and retention ability, it gives full play to the conductive functions of non-metal efficient grounding materials.
The graphite ground wire can be installed by vertical or horizontal embedment. The depth of horizontal embedment is generally from 0.8m to 1.0m (31.50 to 39.37 inches), while that of vertical embedment is from 1.5m to 2.0m (59.05 to 78.74 inches). When a few modules are embedded in parallel, the distance between each other should not be less than 4m (13.12 feet). However, if conditions do not permit, restrictions may be relaxed as appropriate. If vertical embedment is adopted, the heavy modules should be carried down to the foundation trench with iron wires or cords.
The cautions in the operation of the graphite ground wire:
1. The graphite ground wire should be maintained regularly in order to ensure that humidity is in an appropriate range and it is protected from hot, dry and scorching environment. Otherwise, the surface of the module may crack, even though it will not affect the use of products.
2. In transporting and installation, non-metallic graphite ground modules need protections from the damage caused by mechanical forces. When choosing the embedment location, we cannot choose areas that are vulnerable to chemical earth which might lead to corrosion and areas with high temperature.
3. An appropriate amount of water can be sprinkled for compaction in layers during earth filling. After non-metallic graphite ground modules have absorbed moisture for 72 hours, we can measure the initial value of the ground resistance and 15 days later measure the final value. The water content of soils for burying stands at 5%.
4. In cold areas, the non-metallic grounding body should be buried under the permafrost. The graphite ground wire can be installed by vertical or horizontal embedment. The depth of horizontal embedment is generally from 0.8m to 1.0m (31.50 to 39.37inches), while that of vertical embedment is from 1.5m to 2.0m (59.05 to 78.74 inches).
5. When the pole cores of the graphite ground wire are connected in parallel with each other or with the ground wire, welding is needed. It is required to use the same metal material in welding process to ensure the reliability of the connection. The welding length shall not be less than 100mm. No virtual welding or the lack of welding is allowed. When vertical embedding is carried out, jumper welding is required.
Welding slags should be removed at the welding place, and it should be coated with a layer of asphalt or anticorrosive paint in order to prevent the pole cores from corrosion.
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