Electrical equipment grounding belongs to the safety grounding, if it is independent equipment, it should be no more than 4Ω, if it is a public **** grounding should be no more than 1Ω.
Standard grounding resistance specification requirements:
1, independent lightning protection grounding resistance should be less than or equal to 10 ohms;?
2, independent safety protection grounding resistance shall be less than or equal to 4 ohms;?
3. Independent AC working grounding resistance shall be less than or equal to 4 ohms;?
4, independent DC working ground resistance should be less than or equal to 4 ohms;?
5, anti-static grounding resistance is generally required to be less than or equal to 100 ohms?
6, *** with the grounding body (joint grounding) should be no greater than the grounding resistance of 1 ohms.
Expanded Information:
Grounding Resistance Measurement Points of Attention:
1, Grounding Measurement of grounding resistance is sometimes carried out in the field, so the measuring instrument should be sturdy and reliable, with its own power supply, light weight, small size, and strong adaptability to harsh environments.
2, more than 20dB anti-interference ability, can prevent the soil of stray current or electromagnetic induction interference.
3, the instrument should have more than 500kW input impedance, in order to reduce the auxiliary pole probe and soil contact resistance caused by the measurement error.
4, the frequency of the measurement signal within the instrument should be between 25Hz ~ 1kHz, the measurement signal frequency is too low and too high prone to polarization effects, or the increase in inductance between the test pole rod leads, so that the role of inter-lead inductance or capacitance, resulting in a large measurement error, i.e., cloth pole error.
5, in the case of power consumption allows, should try to improve the test current, a larger test current is conducive to improve the anti-interference performance of the instrument.
6, the meter should be simple to operate, the readings are best digital display to reduce the reading error.
Baidu Encyclopedia - Grounding Resistance