UT25A, UT25B, UT25A/B Operations Manual
For UT25A, UT25B as circuit breaker finder/receiver and UT25A/B as socket tester/transmitter
Product Overview
This manual provides detailed information for the UNI-T UT25A, UT25B, and UT25A/B series of electrical testing tools.
Overall Appearances of Circuit Breaker Finder & GFCI Socket Tester
Receiver Appearance
The receiver unit is depicted as an elongated tool with a pointed tip. It features the UNI-T logo and the model name 'UT25A Circuit Breaker Finder'. Numbered labels point to its components: 1. NCV indicator light (specific to UT25B), 2. LED indicator light with line-tracking, 3. ON/OFF switch that also adjusts sensitivity, and 4. The battery compartment for a 9VDC battery (type 1604/6F22).
Attention: Refer to the battery compartment for specific battery information and opening instructions.
Transmitter Appearance
The transmitter unit is shown as a compact device with a standard electrical plug. It displays the UNI-T logo and 'Transmitter for UT25A/B'. Numbered labels indicate its features: 5. GFCI test button, 6. Area for indicator light descriptions, and 7. LED status indicators.
Safety Information
[alert] When this symbol appears, the operator should refer to the Operations Manual to avoid personal injury or damaging the meter.
[alert] When this symbol appears, it hints that there could be potential danger which might lead to severe injury or death if the danger is not avoided.
[caution] When this symbol appears, it hints that there is potential danger which might damage the product if the danger is not avoided.
The product Conforms to UL STD. 61010-1, Certified to CSA STD C22.2 NO. 61010-1.
Product Specifications
Specifications for UT25A and UT25B
| NCV working voltage | 80V (only for UT25B) |
| Operating voltage | 90-120V |
| Operating frequency | 50-60Hz |
| Power | 9VDC, battery type 1604/6F22 |
| Operating temperature | 41°F - 104°F (5°C - 40°C) |
| Storage temperature | 4°F - 140°F (-20°C - 60°C) |
| Operating humidity | At most 80% at temperature of 87°F (31°C) to 50% at temperature of 104°F (40°C) |
| Storage humidity | <80% |
| Operating altitude | 7000 feet (2000m) at most |
| Product weight | 133g (UT25A, UT25B) / 80g (UT25A/B) |
| Product size | L:192xW:54xH:28mm (UT25A, UT25B) / L:103xW:56xH:30mm (UT25A/B) |
| Product certification | ETL |
| ETL list | ETL mark does not indicate the accuracy of estimated readings |
Specifications for UT25A/B
| Working voltage | 110-125V |
| Operating frequency | 50-60Hz |
| Fuse | 1A, 250V, Ø4x11mm |
WARNING: If the equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.
Operations
Circuit Breaker Finder Operation
Warning: Make sure that the circuit is functioning properly before using.
Warning: Make sure the user understands about the equipment.
To find the location of a circuit breaker or circuit protector on a power frequency circuit loop, the transmitter sends out a signal that is received by the receiver. The receiver detects this signal with beeping sounds, allowing the exact position of the circuit breaker or protector to be found by adjusting sensitivity.
This diagram illustrates the operation of the receiver. It shows a panel with multiple circuit breakers. A hand is holding the receiver, scanning downwards across the circuit breakers, indicating the process of locating a specific breaker.
- Plug the receiver into a live socket; two green LEDs will illuminate.
- Unscrew the sensitivity adjusting knob on the receiver from the close position to the highest position; the red LED will turn on. If the red LED does not turn on, please change the battery. It is also necessary to change the battery if the NCV indicator light and line-tracking light are both blinking (only for UT25B).
- During testing, when the receiver is close to the transmitter, it will emit beeping sounds and the LED will blink. The UT25B model first determines if electricity is present. If an AC voltage higher than 80V is detected, the NCV indicator light will blink and beep. Upon detecting the signal from the transmitter, it will automatically test the line-tracking function.
- On the circuit breaker panel, adjust the sensitivity to the highest position, hold the receiver, and scan from top to bottom, as depicted in the figure.
- Move the receiver along the surface of the circuit breaker until the portion of interest is detected.
- While moving the receiver, sensitivity can be reduced to pinpoint the exact circuit breaker.
Indicator Light Description
This section details the meaning of the indicator lights. It presents a table mapping different circuit conditions (e.g., 'CORRECT WIRING', 'GFCI TESTING IN PROGRESS', 'HOT ON NEU WITH HOT OPEN') to specific patterns of three LEDs. Each pattern is represented by a sequence of filled circles (⚫) for ON and empty circles (⚪) for OFF.
| Condition | LED Pattern (Left to Right) |
|---|---|
| CORRECT WIRING | ⚫⚫⚫ |
| GFCI TESTING IN PROGRESS | ⚪⚫⚪ |
| HOT ON NEU WITH HOT OPEN | ⚫⚪⚫ |
| HOT & GND REV | ⚫⚫⚪ |
| HOT & NEU REV | ⚪⚫⚫ |
| OPEN HOT | ⚫⚪⚪ |
| OPEN NEU | ⚪⚫⚪ |
| OPEN GND | ⚪⚪⚫ |
Note: The diagram shows LED patterns as observed from the side of the GFCI buttons. The order will be mirrored if viewed from the opposite side.
⚪ OFF ⚫ ON
- Plug the transmitter into the socket.
- The operator can determine the status of circuit connection based on the 3 LEDs. The diagram above illustrates all possible circumstances for the detected circuit.
- This equipment cannot detect ground connection issues if there are 2 hot wires, a combination circuit, or if the ground and neutral wires are reversed.
GFCI Test on Socket
- Before use, press the GFCI button to ensure it returns to its original position. If not, do not plug the equipment into an electrical circuit and consult a professional electrician. If the button functions correctly, press it on the socket.
- Plug the transmitter into the socket and verify the circuit connection is correct.
- Press the GFCI button for at least 8 seconds. The indicator light will turn off when the GFCI button is released.
- If the GFCI button does not reset, the button itself might be correct, but the wire connection is faulty. Conversely, the wire connection might be correct, but the GFCI button is not functioning.
Changing Battery
- When the battery voltage is low, the indicator lights on the receiver will not turn on. Please change the battery. If the NCV indicator and line-tracking lights are both blinking (UT25B only), change the battery as well.
- Slide open the battery cover following the direction indicated by the arrow on the cover and remove the used battery.
- Install a new 9V battery, paying close attention to polarity.
- Close the battery cover.
- Dispose of the used battery in a designated battery disposal area.
