Grounding resistance testing method (illustrated)
1、 Grounding resistance testing requirements:
a. The grounding resistance for communication work should not exceed 4 Ω;
b. Grounding for safety work, the grounding resistance should not exceed 4 Ω;
c. DC working grounding, the grounding resistance should be determined according to the specific requirements of the computer system;
d. The grounding resistance of lightning protection ground should not exceed 10 Ω;
e. When using joint grounding for shielding systems, the grounding resistance should not exceed 1 Ω.
2、 The ZC-8 grounding resistance tester is suitable for measuring the resistance values of various power systems, electrical equipment, lightning rods, and other grounding devices. It can also measure the resistance value of low resistance conductors and soil resistivity. 3、 This instrument consists of a hand cranked generator, current transformer, sliding line resistor, and ammeter, all of which are housed in a plastic casing with a leather cover for easy portability. The accessories include auxiliary probe wires, etc., which are packed in the accessory bag. Its working principle adopts a reference voltage comparison formula.
4、 Before use, check if the tester is complete. The tester includes the following components.
1. One ZC-8 grounding resistance tester
2. Two auxiliary grounding rods
3. One wire for 5m, 20m, and 40m each
5、 Usage and Operation
1. The wiring method for measuring the grounding resistance value is as follows: the E terminal button on the instrument is connected to a 5m wire, the P terminal button is connected to a 20m wire, and the C terminal button is connected to a 40m wire. The other end of the wire is respectively connected to the grounding electrode E ˊ of the measured object, the potential probe P ˊ, and the current probe C ˊ, and E ˊ, P ˊ, and C ˊ should be kept in a straight line with a spacing of 20m
1.1 When measuring a grounding resistance greater than or equal to 1 Ω, refer to Figure 1 for the wiring diagram. Connect the two E terminals on the instrument together.

The wiring diagram for measuring grounding resistance less than 1 Ω is shown in Figure 2
1.2 When measuring grounding resistance less than 1 Ω, connect the two E-terminal wires on the instrument to the tested grounding body in the wiring diagram to eliminate the influence of wire resistance on the measurement results during measurement