(1) Use the ground resistance tester to prepare

1. Familiar with the instruction manual of the grounding resistance measuring instrument, you should fully understand the structure, performance and usage of the instrument.

2. Prepare all necessary tools and all instrument accessories for the measurement, and wipe the instrument and the ground probe clean, especially the ground probe, the dirt and rust stains that affect the conductivity of the surface must be cleaned.

3. Disconnect the connection point between the grounding trunk and the grounding body or the connection points of all grounding branches on the grounding trunk, so that the grounding body becomes independent from any connection relationship.

(2) Measurement steps using ground resistance tester

1) Insert the two grounding probes into the ground 20m and 40m away from the grounding body along the radiation direction of the grounding body, and the depth of insertion is 400mm.

2) Lay the grounding resistance measuring instrument near the grounding body and connect the wires. The wiring method is as follows:

① Use the shortest special wire to connect the grounding body to the terminal "E1" (three-terminal button measuring instrument) of the grounding measuring instrument or to the common terminal (four-terminal button measuring instrument) shorted to C2,".

②Connect the measuring probe (current probe) 40m away from the grounding body to the terminal "C1" of the measuring instrument with the longest special wire.

③Connect the measuring probe (potential probe) away from the grounding body ⒛m to the terminal "P1" of the measuring instrument with the remaining dedicated wire centered at the length.

3) After placing the measuring instrument horizontally, check whether the pointer of the galvanometer points to the center line, otherwise adjust the "zero adjuster" so that the pointer of the measuring device points to the center line.

4) Place the "magnification scale" (or coarse adjustment knob) at the maximum multiple, and slowly turn the generator handle (the pointer begins to shift), and at the same time turn the "measurement dial" (or fine adjustment) Knob) so that the galvanometer pointer points to the center line.

5) When the pointer of the galvanometer is close to balance (the pointer is close to the center line), speed up the rotation of the handle to make the speed reach 120r/min or more, and adjust the "measurement dial" so that the pointer points to the center line.

6) If the reading of the "measurement dial" is too small (less than 1) and it is difficult to read accurately, it means that the magnification scale multiple is too large. At this time, the "magnification scale" should be set to a smaller multiple, and the "measurement dial" should be readjusted so that the pointer points to the center line and an accurate reading is taken.

7) Calculate the measurement result, that is, R place = "magnification scale" number x "measurement dial" reading.