Selection and Usage of Clamp-on Ground Resistance Tester

I. Selection Points
Measurement Range: Select an appropriate range based on the common grounding resistance values. The main measurement range interval is from 0.01Ω to 2000Ω.
Resolution and Precision: The higher the precision, the higher the equipment price. You can choose according to the actual engineering requirements. A precision of 1% to 3% can basically meet most application scenarios.
Current Measurement Function: If you need to check for leakage current, you can choose a model with an AC current measurement function to enhance practicality.
Data Storage and Transmission: Higher-end models generally come with data storage functions. Some support Bluetooth connection to a computer or mobile APP, making it convenient for data management and report generation.
Quality and Safety: Prioritize choosing equipment with reliable quality assurance. Also, confirm its electrical safety level to ensure it is suitable for the working environment.
II. Operating Steps
Check the Equipment: Confirm that the instrument, clamp, and test cable are undamaged, ensuring the equipment is in a normal state.
Power On Self-Test: After powering on, wait for the instrument to complete the self-test process. Also, ensure the battery is fully charged to avoid interruption during measurement.
Select Function: Use the knob or button to switch the equipment to the “Ground Resistance” measurement mode, preparing to enter the measurement mode.
Cable Clamping Method
Correct Method: Directly clamp a single grounding lead-down line, ensuring the clamp is fully closed, and the cable is in the center of the clamp.
Incorrect Method: Do not clamp multiple cables or flat iron at the same time. Such operation may result in measurement failure or deviation due to magnetic field cancellation.
Read the Result: Keep the instrument stable. Wait until the screen reading stabilizes, and the displayed value on the screen is the measured grounding resistance value.
Record and Analyze: Timely record the measurement results. If there are abnormal readings (such as “OL” over-range, excessive or insufficient values), check if the measurement method is correct or if there are related issues with the grounding system.
III. Usage Notes
Must Form a Circuit: The measured grounding electrode must be part of the grounding system. If it is an independent grounding electrode, use the traditional measurement method.
Clamp Surface Cleaning and Closure: Keep the contact surface of the clamp clean. During measurement, ensure the clamp is fully closed. Otherwise, it will affect the measurement accuracy.
Avoid Interference Sources: During measurement, keep the instrument away from strong magnetic field sources (such as large current busbars, transformers, etc.). Also, keep the grounding lead-down line perpendicular to the clamp surface to reduce external interference.
Pay Attention to the Measurement Object: Do not clamp insulated cables. Directly clamp them on the metal conductor for measurement.