SWEVY Clamp-On Ground Resistance Tester User Manual

1. Introduction

Thank you for choosing the SWEVY Clamp-On Ground Resistance Tester. This instrument is designed for accurate measurement of earth resistance and AC current, suitable for various applications including power systems, substations, industrial facilities, and lightning protection grounding. Please read this manual thoroughly before use to ensure safe and effective operation.

2. Safety Information

Always observe the following safety precautions to prevent electric shock, injury, or damage to the instrument:

• Do not use the instrument if it appears damaged or is operating abnormally.
• Ensure the measurement range is appropriate for the circuit being tested.
• Avoid touching live circuits with bare hands.
• Do not operate in wet environments or during thunderstorms.
• Replace batteries promptly when the low battery indicator appears.
• Only use the instrument for its intended purpose.

3. Product Overview

The SWEVY Clamp-On Ground Resistance Tester features a robust design with intuitive controls.

Key Components:

• Jaw: Opens to clamp around conductors for measurement.
• Lock/Unlock Display/Alarm Value Setting (HOLD button): Used to hold the current reading or set alarm values.
• Trigger: Opens and closes the jaw.
• Function keys (MODE button): Cycles through measurement modes.
• Power On/Off/Exit button: Turns the device on or off, or exits a menu.
• LCD Screen: Displays measurement readings and other information.

4. Specifications

The following table details the technical specifications for the SWEVY Clamp-On Ground Resistance Tester models:

5. Setup

5.1 Battery Installation

The product does not include batteries due to air shipping restrictions. Install four (4) AA alkaline dry batteries (LR6 1.5V) into the battery compartment, observing correct polarity.

5.2 Self-Test Function

The instrument is equipped with a self-test function to ensure accurate operation. Before performing measurements, use the provided calibration test ring.

1. Turn on the instrument.
2. Place the calibration test ring within the clamp jaw.
3. Close the jaw. The instrument will display a reading (e.g., 1.0Ω). This indicates the instrument is functioning correctly.

6. Operating Instructions

6.1 Basic Measurement

To perform a basic measurement:

1. Turn on the device using the Power On/Off button.
2. Ensure the device is in the desired measurement mode (Resistance or AC Current). Use the MODE button to switch between modes.
3. Open the clamp jaw using the trigger.
4. Place the conductor or grounding wire within the jaw.
5. Close the jaw securely. The measurement will be displayed on the LCD screen.
6. Press the 'HOLD' button to freeze the current reading on the display. Press again to release.

6.2 Data Storage and Review

The device can store up to 99 sets of measurement data for easy reference.

1. After a measurement is taken, press the MODE button to save the data. The display will show a storage location number (e.g., '01', '02').
2. To review stored data, cycle through the stored records using the MODE button. The 'mr' symbol will indicate data review mode.
3. If the memory is full, the display will show "mem" symbol.

6.3 Alarm Function Settings

The instrument features an alarm function that alerts the user when measured values exceed a set threshold.

1. In Resistance Measurement Mode or Current Measurement Mode, long press the HOLD key for 3 seconds to enter the alarm threshold setting function.
2. Use the MODE button to adjust the resistance alarm setting (range: 1-199Ω) or current alarm setting (range: 1-499mA, for SW-1200S only).
3. Once set, if a measured value exceeds the configured alarm threshold, the alarm symbol will flash on the display, and the instrument will emit a buzzing prompt.

6.4 Leakage Current / Neutral Measurement (SW-1200S only)

The SW-1200S model supports AC current measurement with a range of 0.00mA to 10.0A, a test current frequency of 50/60Hz, and a maximum resolution of 0.01mA.

1. Switch the instrument to AC Current Measurement Mode using the MODE button.
2. Clamp the jaw around the conductor carrying the AC current.
3. Read the leakage or neutral current value on the LCD screen.

6.5 Grounding Measurement Methods

The clamp meter can be used for various grounding measurement scenarios.

6.5.1 Single-Point Grounding System (Two-Point Method)

This method is applicable when traditional voltage-current methods fail. Find an independent, well-grounded electrode RB near the tested grounding electrode RA (e.g., adjacent water pipes, fire hydrants, buildings). Connect RA and RB with a test wire. The resistance measured by the clamp meter is the series sum of the two grounding resistances and the test wire resistance (RT = RA + RB + RL). If the clamp meter reading is less than the allowable ground resistance, the ground resistance of the two grounding electrodes is considered qualified.

6.5.2 Three-Point Method

This method involves measuring the series sum of two ground resistances at each step to calculate the individual ground resistance of the ground electrode RA.

1. Step 1: Find two independent grounding electrodes RB and RC near the tested grounding electrode RA. Connect RA and RB with a test lead. Read the first data R1 with the clamp meter.
2. Step 2: Connect RC and RA with a test lead. Read the second data R2 using a clamp meter.
3. Step 3: Connect RB and RC with a test lead. Measure the third data R3 with a clamp meter.

Calculations:
In the three steps above, the reading measured at each step is the series sum of the two ground resistances. Thus, each ground resistance value can be easily calculated:

Since: R1 = RA + RB, R2 = RC + RA, R3 = RB + RC
Therefore: RA = (R1 + R2 - R3) ÷ 2

This is the ground resistance value of the ground electrode RA. To facilitate memory of the above formula, consider the three ground electrodes as a triangle, then the measured resistance equals (sum of adjacent side resistances minus opposite side resistance) divided by 2.

Grounding resistance values of the other two reference grounding electrodes are:
RB = R1 - RA
RC = R2 - RA

6.5.3 Multi-Point Grounding System

For multi-point grounding systems (e.g., transmission tower grounding, communication cable grounding, where some buildings are connected via overhead ground wires to form a grounding system), the clamp meter can be used as shown in the figure below. The equivalent circuit is also shown.

Among them: R1 is the predicted grounding resistance.

R0 is the equivalent resistance of the parallel connection of the grounding resistances of all other towers. However, strictly from the perspective of grounding theory, R0 is not the usual value due to the so-called "mutual resistance" effect. In electrical terms, it is slightly higher than the parallel value, but since each tower's grounding hemisphere is much smaller than the distance between towers and there are many grounding points, R0 is much smaller than R1. Thus, from an engineering perspective, we can reasonably assume R0≈0, so the measured resistance should be R1.

Multiple comparative tests with traditional methods under different environments and occasions have proved that the above assumption is completely reasonable.

7. Applications

The SWEVY Clamp-On Ground Resistance Tester is suitable for a variety of fields:

• Power System Testing: For evaluating the grounding of electrical infrastructure.
• Computer Room Grounding Resistance: Ensuring proper grounding for sensitive electronic equipment.
• Building Lightning Protection Grounding: Verifying the effectiveness of lightning protection systems.
• Communication Base Station: Testing grounding for telecommunication equipment.

8. Maintenance

8.1 Cleaning

Wipe the instrument with a soft, dry cloth. Do not use abrasive cleaners or solvents. Ensure the jaws are clean and free of debris for accurate measurements.

8.2 Auto Shutdown Function

To conserve battery life, the instrument features an auto-shutdown function. After 5 minutes of inactivity, the LCD screen will enter a blinking state, and the device will automatically power off after 30 seconds of blinking.

8.3 Storage

When not in use for extended periods, remove the batteries to prevent leakage and store the instrument in a cool, dry place.

9. Troubleshooting

If you encounter issues with your SWEVY Clamp-On Ground Resistance Tester, refer to the following common problems and solutions:

• No Display/Device Not Turning On: Check battery installation and ensure batteries are not depleted. Replace if necessary.
• Inaccurate Readings: Perform the self-test with the calibration ring. Ensure the jaws are clean and fully closed around the conductor. Verify the correct measurement mode is selected.
• "OL" Display: This indicates an overrange overflow. The measured value exceeds the instrument's maximum range.
• Alarm Sounding Continuously: Check the alarm settings. The measured value might be exceeding the set threshold.
• "mem" Symbol Display: The data storage is full. Review or clear stored data as needed.

If the problem persists, contact customer support for assistance.

10. User Tips

• Always ensure a secure clamp around the conductor for accurate readings.
• For critical measurements, take multiple readings and average them.
• Keep the instrument clean and free from dust and moisture to prolong its lifespan.

11. Warranty and Support

This product is covered by the manufacturer's standard warranty. For warranty claims, technical support, or service inquiries, please refer to the contact information provided with your purchase or visit the official SWEVY website.