How to Use the Clamp Ground Resistance Tester
How to Use the Clamp Ground Resistance Tester Note on the Clamp Ground Resistance Tester:
The value of the grounding resistance measured with the clamp grounding resistance meter is the integrated resistance of the grounding branch. It includes the contact resistance, lead resistance and grounding body resistance of the branch to the common ground. With the traditional voltage and current method under the unbuckling condition, the measured value is only the grounding body resistance. Obviously, the former is larger than the latter. The size of the difference reflects the magnitude of the contact resistance between this branch and the common ground.
It should be noted that the grounding resistance specified in the national standard includes the grounding lead resistance. The terminology in DL/T621-1997 “Earthing of AC Electrical Installations†includes the following: “The sum of the resistance to ground and the resistance of the grounding wire of the grounding electrode or natural grounding electrode is called the grounding resistance of the grounding deviceâ€. This rule is also very clear. This is because the lead resistance and grounding body grounding resistance are equivalent in terms of lightning protection safety.
About the use of clamp ground resistance tester:
Clamp-type grounding resistance meters are widely used in grounding resistance measurement and loop resistance measurement in power, telecommunications, meteorology, oil fields, construction and industrial electrical equipment. When measuring a looped grounding system, it is not necessary to disconnect the ground deflector, and no auxiliary electrode is required, which is safe and fast. It can measure the ground fault that cannot be measured by the traditional method and can be used in the place where the traditional method cannot measure because the clamp-type ground resistance meter measures the integrated value of the grounding body resistance and the grounding lead resistance.
The clamp-type grounding resistance meter has a long jaw and a round jaw, as shown in the figure. The long jaws are particularly suitable for flat steel grounding applications. The C-type grounding resistance meter also measures the leakage current and neutral current of the grounding system.
Press the POWER button to boot, first automatically test the LCD display, and its symbols are all displayed, as shown in Figure 1. At the same time, the meter is automatically calibrated. After the power is turned on, it displays “OLΩ†and automatically enters the resistance measurement mode. See Figure 2 if it is not normally powered on. Calibration, the instrument will display "Er" symbol, said the boot error, see Figure 3. The boot error must be checked and restarted.
If “OLΩ†does not appear after the power-on self-test, a larger value is displayed, as shown in Figure 4. However, when testing with a test ring, it can still give correct results. This means that the clamp meter only has a large error when the resistance is measured (eg, greater than 100 ohms), but it still maintains the accuracy when the resistance is measured. The user can still use it with confidence.
About the resistance measurement of the clamp-type grounding resistance tester After the power-on self-test is completed, “OLΩ†is displayed and resistance measurement can be performed. At this point, withhold the trigger, open the jaws, clamp the circuit under test, and read the resistance value.
The user considers it necessary, as shown in Figure 5, to test it with a random test ring. The display value should be consistent with the nominal value on the test loop (5.1Ω). The nominal value on the test ring is a value at a temperature of 20°C. The difference between the displayed value and the nominal value is one word and it is normal. For example, when the nominal value of the test loop is 5.1Ω, it is normal to display 5.0Ω or 5.2Ω.
“OLΩ†is displayed, indicating that the measured resistance exceeds the upper limit of the clamp meter. See Figure 2.
"L0.01Ω" is displayed, indicating that the measured resistance exceeds the lower limit of the clamp meter. See Figure 6.
The symbol is flashing, with an intermittent "beep-beep-beep-" sound, indicating that the resistance under test exceeds the critical value of the resistance alarm.
In the HOLD state, press the HOLD key to exit the HOLD state before continuing to measure.
In the MR state, press the MEM key to exit the MR state before continuing to measure.
When setting the alarm threshold value, press the POWER button or press the AL button for 3 seconds to exit the alarm threshold setting state before continuing the measurement.
* In current test mode, press Ω key to switch to resistance test mode.
Current measurement After the power-on self-test is completed, the clamp meter automatically enters the resistance measurement mode. After “OLΩ†is displayed, press the A key. The clamp meter enters the current measurement mode and displays “AC0.00mAâ€. See Figure 7. At this point, withhold the trigger, open the jaws, clamp the wire under test, and read the current value.
The clamp meter shows “OLAâ€, indicating that the measured current exceeds the upper limit of the clamp meter. See Figure 8.
The symbol is flashing and an intermittent "beep-beep-beep--" sound indicates that the measured current exceeds the set current alarm threshold.
In the HOLD state, press the HOLD key to exit the HOLD state before continuing to measure.
In the MR state, press the MEM key to exit the MR state before continuing to measure.
When setting the alarm threshold value, press the POWER button or press the AL button for 3 seconds to exit the alarm threshold setting state before continuing the measurement.
In resistance test mode, press A key to switch to current test mode.
The value of the grounding resistance measured with the clamp grounding resistance meter is the integrated resistance of the grounding branch. It includes the contact resistance, lead resistance and grounding body resistance of the branch to the common ground. With the traditional voltage and current method under the unbuckling condition, the measured value is only the grounding body resistance. Obviously, the former is larger than the latter. The size of the difference reflects the magnitude of the contact resistance between this branch and the common ground.
It should be noted that the grounding resistance specified in the national standard includes the grounding lead resistance. The terminology in DL/T621-1997 “Earthing of AC Electrical Installations†includes the following: “The sum of the resistance to ground and the resistance of the grounding wire of the grounding electrode or natural grounding electrode is called the grounding resistance of the grounding deviceâ€. This rule is also very clear. This is because the lead resistance and grounding body grounding resistance are equivalent in terms of lightning protection safety.
About the use of clamp ground resistance tester:
Clamp-type grounding resistance meters are widely used in grounding resistance measurement and loop resistance measurement in power, telecommunications, meteorology, oil fields, construction and industrial electrical equipment. When measuring a looped grounding system, it is not necessary to disconnect the ground deflector, and no auxiliary electrode is required, which is safe and fast. It can measure the ground fault that cannot be measured by the traditional method and can be used in the place where the traditional method cannot measure because the clamp-type ground resistance meter measures the integrated value of the grounding body resistance and the grounding lead resistance.
The clamp-type grounding resistance meter has a long jaw and a round jaw, as shown in the figure. The long jaws are particularly suitable for flat steel grounding applications. The C-type grounding resistance meter also measures the leakage current and neutral current of the grounding system.
Press the POWER button to boot, first automatically test the LCD display, and its symbols are all displayed, as shown in Figure 1. At the same time, the meter is automatically calibrated. After the power is turned on, it displays “OLΩ†and automatically enters the resistance measurement mode. See Figure 2 if it is not normally powered on. Calibration, the instrument will display "Er" symbol, said the boot error, see Figure 3. The boot error must be checked and restarted.
If “OLΩ†does not appear after the power-on self-test, a larger value is displayed, as shown in Figure 4. However, when testing with a test ring, it can still give correct results. This means that the clamp meter only has a large error when the resistance is measured (eg, greater than 100 ohms), but it still maintains the accuracy when the resistance is measured. The user can still use it with confidence.
About the resistance measurement of the clamp-type grounding resistance tester After the power-on self-test is completed, “OLΩ†is displayed and resistance measurement can be performed. At this point, withhold the trigger, open the jaws, clamp the circuit under test, and read the resistance value.
The user considers it necessary, as shown in Figure 5, to test it with a random test ring. The display value should be consistent with the nominal value on the test loop (5.1Ω). The nominal value on the test ring is a value at a temperature of 20°C. The difference between the displayed value and the nominal value is one word and it is normal. For example, when the nominal value of the test loop is 5.1Ω, it is normal to display 5.0Ω or 5.2Ω.
“OLΩ†is displayed, indicating that the measured resistance exceeds the upper limit of the clamp meter. See Figure 2.
"L0.01Ω" is displayed, indicating that the measured resistance exceeds the lower limit of the clamp meter. See Figure 6.
The symbol is flashing, with an intermittent "beep-beep-beep-" sound, indicating that the resistance under test exceeds the critical value of the resistance alarm.
In the HOLD state, press the HOLD key to exit the HOLD state before continuing to measure.
In the MR state, press the MEM key to exit the MR state before continuing to measure.
When setting the alarm threshold value, press the POWER button or press the AL button for 3 seconds to exit the alarm threshold setting state before continuing the measurement.
* In current test mode, press Ω key to switch to resistance test mode.
Current measurement After the power-on self-test is completed, the clamp meter automatically enters the resistance measurement mode. After “OLΩ†is displayed, press the A key. The clamp meter enters the current measurement mode and displays “AC0.00mAâ€. See Figure 7. At this point, withhold the trigger, open the jaws, clamp the wire under test, and read the current value.
The clamp meter shows “OLAâ€, indicating that the measured current exceeds the upper limit of the clamp meter. See Figure 8.
The symbol is flashing and an intermittent "beep-beep-beep--" sound indicates that the measured current exceeds the set current alarm threshold.
In the HOLD state, press the HOLD key to exit the HOLD state before continuing to measure.
In the MR state, press the MEM key to exit the MR state before continuing to measure.
When setting the alarm threshold value, press the POWER button or press the AL button for 3 seconds to exit the alarm threshold setting state before continuing the measurement.
In resistance test mode, press A key to switch to current test mode.
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