How to use a multimeter to measure whether the grounding is good or bad
Anyone who knows electricity knows that the grounding wire is important, and grounding can play a life-saving role in critical situations. For the grounding wire to work, it must be connected from the grounding hole of the three-hole socket, to the home grounding trunk, to the grounding trunk of the entire building, and then to the grounding pole to remain connected. Generally, the grounding resistance should be less than 4 ohms.
How to use a multimeter to measure whether the grounding is good or bad? Generally, you can use the resistance setting of a multimeter, connect a test lead to the ground hole of the socket, and connect one end to buried steel bars, ironware, or even steel water pipes entering the home. If the measured resistance value is relatively small (in It can range from a few ohms to dozens of ohms, because this measurement method is only approximate, and we cannot guarantee that the buried steel bars and household steel water pipes are well grounded), then it can basically be judged that the grounding wire is effective. If the measured resistance is several hundred ohms or even several megohms, it can be basically judged that the ground wire is failed. Of course, if you want to measure accurately, you need to use a grounding megger or a grounding resistance tester to test the grounding resistance.
The reasons for grounding failure are as follows: First, the grounding pole of the socket is not connected to the grounding wire or the grounding wire is not connected. Second, there is a break in the ground wire. Third, the ground wire is not connected to the ground electrode. Fourth, there is no grounding electrode at all.
However, in household electricity use, whether the ground wire is connected and whether it is effective. The answer should be no.
As far as I know, most rural power supplies do not have a grounding wire. The main wires of the power grid are usually two wires, zero and hot. The grounding of rural households is generally useless. In general, self-built houses in rural areas basically have no awareness to bury the grounding electrode by themselves. Furthermore, the water and electricity installation of self-built houses in rural areas are done by some electricians, who are not interested in doing grounding, and finally install the grounding electrode by themselves. Ground wire will increase material and labor costs. Standardizing the safe use of electricity in rural areas is a relatively long process.
