Compared with conductors such as copper or aluminum cables, Earth Resistance Tester the ground surface is a relatively poor conductor. However,Earth Resistance Tester considering the great quality of the ground surface,Earth Resistance Tester it provides a large area for the current, so the resistance to current may be very low,Earth Resistance Tester and as a result,Earth Resistance Tester the ground surface can be considered as a good conductor. The internal live parts of electrical equipment and the external metal chassis are insulated and provide protection against electric shock by direct contact. When an insulation fault occurs,Earth Resistance Tester the potential of the metal chassis of the device becomes the power supply voltage, so a potential difference with respect to the ground will occur.

Therefore, if there is no proper grounding and protection, when the human body touches the chassis,Earth Resistance Tester due to the potential difference on the human body, current will flow from the human body to the ground through the chassis,Earth Resistance Tester which may cause a fatal electric shock. If the metal casing is grounded,Earth Resistance Tester the fault current will be shunted. Therefore, most of the fault current flows through the grounded protective conductor and into the ground because the resistance of the grounding path is designed to be much lower than the resistance of the human body. Therefore, Earth Resistance Tester only a small amount of harmless current flows through the human body. If a fault is caused due to the value and duration of the dangerous touch voltage and causes a harmful effect on people,Earth Resistance Tester the power supply needs to be automatically disconnected. The correct coordination and design of the grounding resistance measuring instrument and the protection device will ensure that the power supply is automatically disconnected. What element does the earth resistance measuring instrument mainly detect?

The resistance of the ground wire and the ground electrode,Earth Resistance Tester the contact resistance between the ground electrode and the ground, the ground resistance or better ground resistance are characteristics of grounding. Generally,Earth Resistance Tester it is recommended to insert the electrode of the grounding resistance measuring instrument as deep as possible into the ground, Earth Resistance Tester in damp soil to reduce the grounding resistance to a low level. In addition,Earth Resistance Tester no matter how the season changes, the electrode should be installed in a place where the temperature is stable,Earth Resistance Tester that is, below the frost line.

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