UNI-T UT25CL Cable Locator User Manual

1. Overview

The UNI-T UT25CL Handheld Cable Locator is designed to detect the path of low-voltage cables buried in the ground (such as cabling inside walls), test and diagnose opens, shorts, and other problems occurring in cabling, and detect if the tested cable is energized. The transmitter can display corresponding voltages (voltage of energized cable: ≥8V), and the receiver can simultaneously display the signal strength, transmitter code, transmitter power level, low battery, etc. The UT25CL offers accurate measurement, easy operation, and a visualized display, making it an ideal tool for low-voltage cabling engineering, maintenance, and metal conductor work.

Figure 1.1: UT25CL Cable Locator (Transmitter and Receiver)

1.1 Accessories

Upon opening the package, verify that all accessories are present and undamaged:

• UT25CL-T transmitter: 1 pc
• UT25CL-R receiver: 1 pc
• Dual in-line test leads (red + black): 1 pair
• Alligator clips (red + black): 1 set
• Lantern-tip test probe (red + black): 1 pair
• AC polarized plug wire: 1 pc
• Quick guide start: 1 pc
• 1.5V AA alkaline battery: 6 pcs
• 1.5V AAA alkaline battery: 6 pcs

Figure 1.2: Included Accessories

2. Safety Information

Warning: To avoid electric shock, fire, or personal injury, read this manual thoroughly, especially the safety instructions.

2.1 Electrical Symbols

2.2 General Safety Instructions and Precautions

• Always keep this manual in an easily accessible place for future reference.
• Adhere to all safety instructions and warnings affixed to the product. Failure to do so may compromise the protection provided by the Meter.
• Before each use, inspect the Meter and test leads for damage. Replace damaged test leads immediately with approved replacements.
• Discontinue use immediately if any problem is found (e.g., bare test lead, damaged casing, abnormal display).
• Do not modify the internal wiring of the Meter.
• Avoid using or storing the Meter in high temperature or high humidity environments.
• Ensure the Meter's cover is closed properly during operation to prevent electric shock.
• Keep hands, shoes, clothing, ground, circuits, and components dry during use.
• Avoid contact with bare wires, connectors, or unused input terminals when measuring.
• Exercise caution when working with voltages over 30V (DC/AC). Always grip test leads behind the finger guard.
• Set the Meter to the maximum range if the measured range is unknown. Do not exceed specified extreme limits.
• Do not apply overrated voltage or current between terminals or between any terminal and earth ground.
• Remove test leads before opening the battery cover.
• If the low battery symbol appears, replace batteries immediately to ensure accuracy.
• Ensure batteries are installed with correct polarity.
• Remove batteries if the product is not used for a long time to prevent leakage.
• Battery acid is corrosive. If contact occurs, rinse with water immediately and seek medical attention if eyes are affected.
• Keep batteries out of reach of children and pets.
• Do not dismantle, short-circuit, or dispose of batteries in fire. Non-rechargeable batteries must not be charged.
• Power off the Meter and disconnect all accessories before cleaning or maintenance.
• Do not immerse the Meter in water or other liquids. Wipe with a damp cloth and mild detergent; do not use abrasives or solvents.
• Calibration and maintenance must be performed by qualified personnel.
• If equipped with a replaceable fuse, power off the Meter and disconnect all cables before replacement. Use only fuses with the designated type and current rating.

3. Product Components

3.1 Transmitter (UT25CL-T)

Figure 3.1: UT25CL-T Transmitter

• Input/Output Terminal: Connects accessories for signal measurement/output.
• LCD Screen: Displays information with backlight.
• ELV Indicator Light: Lights red and increases brightness if input voltage exceeds specified level when powered off.
• START/STOP Button: Short press to start/stop signal transmission.
• Up/Down Buttons: Used to set CODE (0-7, default 5) and LEVEL (I, II, III, default III) when transmission is stopped.
• Backlight/Mute Button: Short press to toggle backlight, long press to toggle mute mode.
• LEVEL Button: Short press to enter/exit LEVEL setting.
• CODE Button: Short press to enter/exit CODE setting.
• Power Button: Long press (>1s) to turn on/off the transmitter.
• Buzzer: Provides audible indications.

3.2 Receiver (UT25CL-R)

Figure 3.2: UT25CL-R Receiver

• Cable Tracking End & NCV Sensor: For cable tracking and non-contact voltage detection.
• LCD Screen: Displays information with backlight.
• AUTO/MANUAL Button: Switches between AUTO and MANUAL modes in cable tracking.
• UP Button: Increases reception sensitivity in MANUAL mode; switches to AUTO mode if sensitivity is at maximum.
• DOWN Button: Switches to MANUAL mode from AUTO; decreases reception sensitivity in MANUAL mode.
• Flashlight Button: Short press to turn on/off the flashlight.
• NCV Button: Switches between cable tracking and NCV modes.
• Power Button: Long press (>1s) to turn on/off the receiver.

4. Setup and Operation

4.1 Transmitter Settings

4.1.1 CODE Setting

1. The default code is 5 when the transmitter is powered on.
2. In power-on state (transmission not started), short press the START/STOP button to stop transmission if it's active. Short press the CODE button; the CODE symbol will flash for 0.5s.
3. While the CODE symbol flashes, use the Up/Down buttons to set the code (0-7). The default is 5.
4. Short press the CODE or LEVEL button, or START/STOP button to exit the code setting.

Figure 4.2: 8 Types of Code Signals

4.1.2 LEVEL Setting

1. The default level is III when the transmitter is powered on.
2. In power-on state (transmission not started), short press the START/STOP button to stop transmission if it's active. Short press the LEVEL button; the LEVEL symbol will flash for 0.5s.
3. While the LEVEL symbol flashes, use the Up/Down buttons to set the level (I, II, or III). The default is III.
4. Short press the LEVEL or CODE button, or START/STOP button to exit the level setting.

Figure 4.4: 3 Levels of Signal Strength

4.2 Receiver Settings

4.2.1 Auto/Manual Mode Setting (Cable Tracking Mode)

1. The receiver defaults to AUTO scanning mode upon power-on.
2. Short press the AUTO/MANUAL button to switch to MANUAL scanning mode (default reception level 6).
3. In AUTO scanning mode, short press the DOWN button to switch to MANUAL mode (default reception sensitivity: 6).
4. In MANUAL scanning mode, if reception sensitivity is 8, short press the UP button to switch to AUTO mode.

4.2.2 Adjusting Reception Sensitivity in MANUAL Mode

1. Power on the receiver to enter MANUAL mode (default reception sensitivity: 6).
2. In MANUAL mode, short press the UP button to adjust sensitivity from 0 to 8. At sensitivity 8, short press UP to switch to AUTO mode.
3. In MANUAL mode, short press the DOWN button to adjust sensitivity from 8 to 0. In AUTO mode, short press DOWN to switch to MANUAL mode.

4.2.3 NCV Mode Switching

1. In AUTO or MANUAL cable tracking mode, short press the NCV button to switch to NCV mode.
2. In NCV mode, short press the NCV button to switch back to AUTO mode (cable tracking mode).

4.3 Key Applications

4.3.1 Tracking Energized and Deenergized Cables

To track cables, independent grounding is recommended to avoid signal counteraction. Connect the red test lead of the transmitter to the live wire of the circuit and the black test lead to an independent ground (e.g., water pipe, grounding spike, metal structure, or outlet grounding connection of another circuit). This ensures the strongest signal intensity.

4.3.2 Tracking Underground Cables

The UT25CL can track both energized and deenergized cables buried underground. The method is similar to locating cables in walls. Use independent grounding for best results.

Figure 4.8: Low-voltage Cable (Path) Detection

4.3.3 Identifying Circuit Breakers and Fuses

To identify the correct circuit breaker or fuse, the cable locator determines the location by signal strength and coding accuracy. For circuit breakers, connecting directly to live and neutral wires is often sufficient as conductors at the panel are independent. For best results, especially if cable tracking is also needed, use independent grounding.

Figure 4.10: Identifying Circuit Breakers and Fuses

4.3.4 NCV Mode and Passive Tracking

The NCV (Non-Contact Voltage) mode allows testing if a cable is energized or tracking it without the transmitter. The receiver can detect and track energized cables (80V~1000V AC, 50/60Hz) without current flowing through them. For safety, always confirm if the circuit is energized with a tester before working.

Figure 4.11: Non-contact NCV Function (Receiver only)

4.3.5 Identifying Specific Cable in Multi-Core Cable

A specific target cable can be quickly found in a multi-core cable. Multiple UT25CLT transmitters can be used simultaneously with different encodings (up to 8 transmitters). The strongest signal indicates the correct cable.

Figure 4.12: Identifying Specific Cable in Multi-Core Cable

4.3.6 Locating Breakpoints/Opens

Even if the cable is in a wall, ground, or ceiling, breakpoints can be accurately identified in precise tracking mode. Ensure the cable is deenergized. Connect the transmitter and track the cable. The signal will stop at the fault location. To confirm, move the transmitter to the other end and track again; if the signal stops at the same point, the fault is located.

Figure 4.14: Low-voltage Cable (Open Circuit Fault) Detection

4.3.7 Locating Shorts

Shorted cables can trigger circuit breakers. Disconnect the cable and ensure conductors are isolated. If residual charges are present, disconnect power before testing. Connect the transmitter test leads to the shorted cables. The receiver will output a signal, which will weaken dramatically and disappear at the short-circuit point.

Figure 4.16: Low-voltage Cable (Short-Circuit Fault) Detection

4.3.8 External Voltage Measurement and ELV Function (Transmitter only)

The transmitter can measure AC/DC voltage in the range of 8-480V. It also recognizes DC voltage polarity. The ELV (Extra-Low Voltage) function turns on when the port access voltage is greater than 25V, with the indicator light's brightness increasing with voltage.

Figure 4.17: Voltage Measurement and ELV Functions

5. Specifications

5.1 Transmitter Specifications (UT25CL-T)

5.2 Receiver Specifications (UT25CL-R)

Figure 5.3: Technical Specifications

6. Maintenance

6.1 Battery Replacement (UT25CL-T Transmitter)

The transmitter uses 6 pieces of AA alkaline batteries. Batteries are not preinstalled.

1. Ensure the transmitter is powered off and all test leads are removed.
2. Use a screwdriver to loosen the screws on the battery compartment.
3. Remove the battery cover.
4. Install new batteries, observing correct polarity.
5. Reinstall the battery cover and fasten the screws.

Battery Type and Threshold (Transmitter)

Battery type: AA LR06 alkaline battery (6 pieces connected in series)

• >8V to 9V: Level 4 battery symbol displayed.
• >7.2V to ≤8V: Level 3 battery symbol displayed.
• >6.6V to ≤7.2V: Level 2 battery symbol displayed.
• >6.2V to ≤6.6V: Level 1 battery symbol displayed.
• <6.2V: Batteries run out of power. The battery symbol flashes three times (2Hz) and the transmitter powers off.

6.2 Fuse Replacement (UT25CL-T Transmitter)

If the transmitter is equipped with a replaceable fuse:

1. Power off the Meter and disconnect all measured cables.
2. Dismantle the battery compartment and remove the batteries.
3. Loosen the screws on the rear cover and remove it.
4. Use a tool to take off the fuse.
5. Install a new fuse of the same type and current rating.
6. Reinstall the rear cover and fasten the screws.
7. Reinstall the battery cover and fasten the screws.

6.3 Battery Replacement (UT25CL-R Receiver)

The receiver uses 6 pieces of AAA alkaline batteries.

1. Ensure the receiver is powered off and disconnected from all circuits.
2. Use a screwdriver to loosen the screw on the battery compartment.
3. Remove the battery cover.
4. Install new batteries, observing correct polarity.
5. Reinstall the battery cover and fasten the screw.

Battery Type and Threshold (Receiver)

Battery type: AAA LR03 alkaline battery (6 pieces connected in series)

• >8V to 9V: Level 4 battery symbol displayed.
• >7.2V to ≤8V: Level 3 battery symbol displayed.
• >6.6V to ≤7.2V: Level 2 battery symbol displayed.
• >6.2V to ≤6.6V: Level 1 battery symbol displayed.
• <6.2V: Batteries run out of power. The battery symbol flashes three times (2Hz) and the transmitter powers off.

7. Troubleshooting

• No Signal or Weak Signal:
  • Ensure proper connection of test leads to the transmitter and the circuit.
  • Verify that the transmitter is powered on and transmitting.
  • Check battery levels in both transmitter and receiver.
  • Ensure independent grounding is used for optimal signal strength, especially for cable tracking.
  • Adjust the signal strength (LEVEL) on the transmitter and sensitivity on the receiver.
  • For cables in metal pipes, the receiver cannot penetrate the metal, so direct contact or alternative methods may be needed.
• Incorrect Fault Location:
  • For breakpoints, ensure the cable is deenergized.
  • For shorts, ensure conductors are isolated and power is disconnected if residual charges are present.
  • Adjust transmitter signal strength (LEVEL) to II or I to reduce coupling with adjacent cables/metal objects, preventing ghost signals.
  • When identifying circuit breakers, scan multiple times and adjust sensitivity to pinpoint the strongest signal.
• GFCI Triggering:
  • If connecting the transmitter to a GFCI-protected circuit, using independent grounding might trigger the GFCI. Consider connecting the test lead to neutral and live wire (which may reduce signal strength) or switching off the circuit power.
• Interference from Dimmers:
  • Dimmers can create electrical noise. When locating circuit breakers or fuses in systems with dimmers, turn off the dimmer (disconnect the light switch) to prevent incorrect readings.

8. User Tips

• Underground Cable Detection: For effective underground cable detection, it is recommended to attach the transmitter to one end of the cable. This provides a clear signal for the receiver to trace the path.
• Signal Strength Adjustment: When tracking cables, especially in complex environments or near other conductors, experiment with the transmitter's signal strength (LEVEL) and the receiver's sensitivity. Lower signal levels can help pinpoint exact locations by reducing interference from adjacent cables.
• Independent Grounding: Always prioritize using independent grounding for the transmitter when possible. This significantly improves signal clarity and accuracy, especially for tracing long runs or in noisy electrical environments.
• Multi-Core Cables: When dealing with multi-core cables, remember that the UT25CL can differentiate between individual wires by using different code signals from multiple transmitters. This is crucial for identifying a specific wire without guesswork.

9. Warranty and Support

Uni-Trend guarantees that the product is free from any defect in material and workmanship within one year from the purchase date. This warranty does not apply to damages caused by accident, negligence, misuse, modification, contamination, or improper handling. The dealer shall not be entitled to give any other warranty on behalf of Uni-Trend. If you need warranty service within the warranty period, please contact your seller directly.

Uni-Trend will not be responsible for any special, incidental, or subsequent damage or loss caused by using the device.