The method of measuring resistance when one wire from the measuring unit goes to the grounding and another to the metal rod buried into the ground is considered to be the simplest and less precise, that is why it is rarely used. However there are applications when it is necessary to get an estimation of the resistance value in the conditions of lack of free space for the second rod. Two-wire method demonstrates its advantages here.
|поверхность земли||ground surface|
|проводник заземления||protective ground conductor|
|штырь заземления||grounding rod|
|выходы прибора закорочены перемычкой||device outputs are shorted by a bridge cable|
|вспомогательный штырь (X и Y замкнуты)||auxiliary rod (X and Y are terminated)|
The principle of two-wire measuring of ground resistance comprises the following. We create some grounding, for example, we bury a metal rod into the ground and suppose it deliberately has a cut-off resistance value.
You can read more details about these methods in the article "Two-wire method of grounding resistance measuring: "pro" and "contra".