How to use and precautions for ground resistance tester

1. Place the instrument in a horizontal position and check whether the pointer of the galvanometer is on the center line. If not, use the zero adjuster to adjust it to the center line.

2. Set the "multiplication scale" to the maximum multiplication, slowly turn the crank of the generator, and at the same time turn the "measurement scale" so that the pointer of the galvanometer points to the center line.

3. When the pointer of the galvanometer is close to balance, increase the speed of the generator crank to more than 120 revolutions per minute, and at the same time adjust the "measuring dial" so that the pointer points to the center line.

4. If the reading on the "measurement dial" is less than 1, the magnification should be set to a smaller multiple and the "measurement dial" should be readjusted to obtain the correct reading.

5. When filling in this record, a plan view of the resistance test points should be attached and the test points should be numbered sequentially.

Ground resistance tester precautions

1. The grounding line must be disconnected from the protected equipment to ensure the accuracy of the measurement results.

2. There should be no stray current or polarized soil near the measured ground pole.

3. Measurement cannot be performed after rain, when the soil absorbs too much water, or when the climate, temperature, pressure, etc. change dramatically.

4. The detection needle should be kept away from large metal objects such as underground water pipes, cables, and railways. The current pole should be kept at least 10m away, and the voltage pole should be kept at least 50m away. If the above-mentioned metal objects are not connected to the grounding grid, the distance can be shortened by 1/2~1/3.

5. The connecting wires should use well-insulated wires to avoid leakage.

6. Pay attention to the position where the current electrode is inserted into the soil, and the grounding rod should be at zero potential.

7. The test should be carried out when the soil resistivity is high, such as in early winter or in the dry season of summer.

8. There must be no electrolytes or rotting corpses at the test site to avoid illusions.

9. When the sensitivity of the galvanometer is too high, the voltage pole of the potential probe can be inserted shallower into the soil. When the sensitivity of the galvanometer is not enough, water can be injected along the probe to make it moist.

10. Check the accuracy of the instrument at any time