Q: What Are The Features Of The Clamp Ground Resistance Tester?

A: The Clamp Ground Resistance Tester is suitable for grounded systems with loops. It does not require disconnecting the ground lead or auxiliary ground electrodes, making it safe, fast, and easy to use. It can measure ground faults that traditional methods cannot detect and is applicable in scenarios where traditional methods are ineffective. This is because the tester measures the combined resistance of the ground body and the ground lead. Additionally, some models can measure leakage current and neutral line current in the grounding system.

Q: What Are The Components Of The Clamp Ground Resistance Tester?

A: The Clamp Ground Resistance Tester consists of a clamp head, buttons, and an LCD screen. The clamp head handles the core measurement function, the buttons correspond to various operational features, and the LCD screen displays measurement values, battery level, and other information.

Q: How To Determine If A Loop Is Formed On Site?

A: The basic principle of the Clamp Ground Resistance Tester is to measure loop resistance. For example, the resistance ring included in the accessories represents a simple loop resistance. On site, clamp the tester into the loop and observe the measurement value. If the display shows "OL" (infinity), no loop is formed, indicating single-point grounding. Common examples of single-point grounding include single ground leads (e.g., copper cables, flat steel) and grounding flat iron for independent lightning rods or small towers. If a measurement value appears, further analysis is required based on the value and site conditions.

Q: Why Does The Instrument Display "Er" On The Screen When Powered On?

A: For detailed handling of this issue, please refer to the article: Handling And Maintenance Of Clamp Resistance Meter Displaying "Er".

Q: Why Does The Instrument Screen Show Jumping Values Or A Dash Symbol When Powered On?

A: After normal power-on self-test, the instrument should display "OL". If it shows jumping values or a dash symbol instead, the measurement function of the clamp head may be impaired. Press the handle to open the clamp head and inspect the contact surface for stains, debris, or scratches. Use a dry, soft lint-free cloth (e.g., glasses cloth) to wipe the clamp head while the instrument is off until it is clean and dry. After wiping, restart the instrument. If it displays "OL" and accurately measures the 1Ω resistance ring from the accessories, the instrument has returned to normal operation.

Q: If A Large Value Appears When Powered On, Can The Instrument Still Be Used Normally?

A: If the post-self-test display shows a large resistance value instead of "OL", but the tester still provides correct results with the test ring, it indicates that the clamp meter has significant errors only when measuring high resistance (above 200Ω), while maintaining accuracy for low resistance (below 200Ω). Users can continue to use it confidently.

Q: Why Does The Screen Value Fluctuate Unstably After Clamping The Instrument Into The Measured Circuit?

A: The clamp section of the meter comprises a voltage coil and a current coil. The voltage coil supplies an excitation signal, inducing a potential E in the measured circuit. This potential E generates a current I in the circuit. The meter measures E and I to calculate resistance R using R=E/I. If the value fluctuates after clamping, check for existing current or voltage in the measured circuit, as these can interfere with measurement. Generally, higher current or voltage in the circuit leads to greater measurement errors.

Q: Why Does The Clamp Head Of The Instrument Make Sound?

A: During resistance measurement, the clamp head emits a continuous slight humming sound, which is normal and does not affect accuracy. Note that this differs from the buzzer alarm sound triggered by the instrument’s alarm function. When the alarm is enabled, an alarm symbol will appear on the display.

Guangdong ETCR Technology Co., Ltd. specializes in the research, development, and production of power test instruments and power supply quality management systems. With nearly two decades of experience in the power industry, the company adheres to a path of technological innovation and independent research and development, meticulously crafting each product and providing attentive service to every customer. It actively supports OEM & ODM customization services, tailoring solutions to meet specific client needs and deliver greater value. Yidian Measurement and Control is the manufacturer of the ETCR EM2000 Clamp Earth Resistance Tester, ETCR EM2000B+  Explosion Proof Type Clamp Earth Resistance Tester, ETCR EM2150 Loop Resistance Tester, ETCR EM2200 Multi-Function Clamp Earth Resistance Tester, EM2800 series, and EM2900 series Non-Contact type Earth Resistance On-line Detector， For assistance, contact the ETCR service hotline: +86 13802922567, or visit the official website: www.etcrmeter.com.