Measurement method and principle of grounding resistance tester

1、 What is grounding?
Grounding is a low resistance connection between a circuit or device and the ground. Any electrical system requires appropriate wiring and grounding to achieve safe operation of equipment. Proper wiring requires that the system, all loads, and circuit components be properly grounded and comply with industry standards, IEEE, and other recognized organizational standards, guidelines, and recommendations.
2、 What is grounding resistance?
The grounding resistance refers to the resistance encountered when the current flows from the grounding device to the ground and then flows through the ground to another grounding body or spreads to a distance. It includes the resistance of the grounding wire and the grounding body itself, the contact resistance between the grounding body and the ground resistance, and the electrical resistance between two grounding bodies or the ground resistance from the grounding body to an infinite distance. The size of the grounding resistance directly reflects the good degree of contact between the electrical device and the "ground", and also reflects the scale of the grounding network. Under the conditions of single point Earthing system and strong interference, the measurement method of auxiliary ground level can be used for measurement. The grounding resistance is mainly divided into the following three types:
1. Protective grounding: The metal casing of electrical equipment, concrete, poles, etc., may be electrified due to insulation damage. To prevent this situation from endangering personal safety, grounding is set up.
2. Anti static grounding: Prevent the grounding of flammable fuel, natural gas storage tanks, pipelines, electronic equipment, etc. due to the influence of static electricity hazards.
3. Lightning protection grounding: In order to introduce lightning into the ground, connect the grounding terminal of lightning protection equipment (Lightning rod, etc.) with the ground to eliminate the grounding of lightning overvoltage on electrical equipment, personal property, also known as overvoltage protection grounding.