The correct way to use the ground resistance tester and measure the ground resistance is:
The E end button on the instrument is connected to a 5m wire, the P end button is connected to a 20m wire, and the C end button is connected to a 40m wire. The other end of the wire is connected to the ground electrode E, the potential probe P, and the current probe C, respectively, and the E, P, and C are kept straight.
The grounding resistance is installed at the point where the current flows from the grounding device into the ground and then flows through the ground to another grounding body or diffuses to a distance. The grounding resistance value reflects the good contact degree between the electrical device and the ground and reflects the scale of the grounding network. The ground resistance meter is mainly composed of hand generator, current transformer, potentiometer and galvanometer.
The introduction of grounding technology was originally to prevent electrical or electronic equipment from being struck by lightning and take protective measures, the purpose is to introduce the lightning current generated by lightning into the earth through the lightning rod, so as to protect the building.
At the same time, grounding is also an effective means to protect personal safety, when the phase line caused by some reason and the equipment shell contact, the equipment shell will have a dangerous voltage, the resulting current will be through the ground wire to the earth, thus playing a role in personal safety protection.
Extended data
earth resistance tester
The ground resistance meter is suitable for measuring small resistance. The ground resistance meter abandons the traditional manual power generation mode, adopts advanced large-scale integrated circuit, and uses DC\/AC conversion technology to combine the three-terminal button and four-terminal button measurement methods into a new type of digital ground resistance tester. Applicable to power, post and telecommunications, railway, communication, mining and other departments to measure the ground resistance of various devices and to measure the conductor resistance of low resistance; Soil resistivity and ground voltage can also be measured. The ground resistance tester should be kept indoors to keep its ambient temperature 0 ° C ~ 40 ° C, the relative humidity does not exceed 80%, and the air cannot contain harmful substances sufficient to cause corrosion.