MASTECH MS5902 Automatic Circuit Breaker Finder & Socket Tester User Manual

1. Product Overview

The MASTECH MS5902 is a versatile tool designed to automatically and quickly identify the correct circuit breaker or fuse for a specific circuit. It also functions as a socket tester to quickly identify wiring conditions. This device is suitable for renovation, installation, and acceptance testing of power grids in homes, offices, and factories. It features buzzers and lights for indication, a flashlight for dark environments, and a low voltage alarm for the battery.

Figure 1: MASTECH MS5902 Circuit Breaker Finder (Receiver) and Socket Tester (Transmitter)

Figure 2: Components of the MS5902 Receiver and Transmitter

• Receiver (MS5902R): Induction head, Low voltage indicator, Status Indicator, Switch, Light switch.
• Transmitter (MS5902TD): Indicator lights for wiring status (TONE, ON, PULSE, CORRECT, MISSING EARTH, LIVE EARTH REVERSE, LIVE NEUTRAL REVERSE, MISSING NEUTRAL), Breaker Find/Socket Test switch.

2. Safety Information

• Always exercise extreme caution when using the MS5902, especially in large circuit breaker panels.
• Do not use the device when the voltage exceeds 120V AC (for US version) or 230V AC (for EU version).
• Ensure the battery is properly installed before use.
• Do not attempt to repair or modify the device. Refer to qualified personnel for service.

3. Specifications

Figure 3: Dimensions of the MS5902 Receiver and Transmitter

4. Setup

4.1 Battery Installation

The MS5902 requires a 9V battery (not included) for operation. To install or replace the battery in the receiver (MS5902R):

1. Locate the battery compartment on the back of the MS5902R receiver.
2. Unscrew the cover of the battery compartment.
3. Insert a new 9V battery, ensuring correct polarity.
4. Replace the cover and secure it with the screw.

The transmitter (MS5902TD) does not require a battery as it draws power from the socket it is plugged into.

5. Operating Instructions

5.1 Locating a Circuit Breaker or Fuse

1. Prepare the Transmitter: Ensure the switch on the transmitter (MS5902TD) is set to the "Breaker Find" position (pillar at left).
2. Plug in the Transmitter: Plug the MS5902TD transmitter into the receptacle of the circuit you wish to test.
   • If testing a candescent light fixture, install a socket adapter (purchased separately) and ensure the light switch is OFF before plugging in the MS5902TD. Then, turn the light switch ON.
3. Activate the Receiver: Go to the circuit breaker panel box. Turn on the MS5902R receiver by pressing its power button. The red LED on the receiver should light up.
4. Scan Breakers: Place the induction head of the MS5902R directly onto each circuit breaker or fuse along both sides of the panel.
5. Identify the Breaker:
   • As you slide the receiver down each breaker, it will beep frequently, indicating the relative signal strength.
   • Move the MS5902R down each breaker once more. On the third pass, the MS5902R will emit a distinct beep, the red LED will turn off, and the green LED will light up ONLY at the circuit breaker powering the MS5902TD transmitter. This indicates the correct breaker.
6. Verify: Push the identified breaker to the OFF position. Check that the LED on the MS5902TD transmitter in the outlet turns off. This confirms you have found the correct breaker or fuse.

Figure 4: Using the MS5902R Receiver to locate a circuit breaker

Figure 5: MS5902TD Transmitter plugged into an EU socket for testing

5.2 Testing a Socket

To test the wiring condition of a socket:

1. Prepare the Transmitter: Ensure the switch on the transmitter (MS5902TD) is set to the "Socket Test" position (pillar at right).
2. Plug in the Transmitter: Plug the MS5902TD transmitter into the socket you wish to test.
3. Read Indicators: Observe the indicator lights on the MS5902TD. The combination of lit LEDs will indicate the wiring condition of the socket. Refer to the nameplate on the MS5902TD for the meaning of each light pattern.

Figure 6: MS5902TD Transmitter plugged into a US socket for testing

5.3 Flashlight Function

The MS5902R receiver includes a flashlight function for use in dark environments.

• Press the "Light switch" button on the MS5902R to turn the flashlight ON or OFF.

Figure 7: Flashlight on the MS5902R Receiver

6. Maintenance

• Cleaning: Keep the device clean with a dry cloth. Do not use abrasive cleaners or solvents.
• Battery Replacement: When the yellow LED on the MS5902R receiver lights up, it indicates a low battery. Replace the 9V battery as described in the "Battery Installation" section (4.1).
• Storage: Store the device in a cool, dry place away from direct sunlight and extreme temperatures. Remove the battery if storing for extended periods to prevent leakage.

7. Troubleshooting

8. User Tips

• Slow and Steady: When scanning for breakers, move the receiver slowly and deliberately over each breaker for best accuracy.
• Verify with Power Off: After identifying a breaker, always double-check by turning it off and confirming the power is cut to the intended outlet before performing any electrical work.
• Socket Adapter: For light fixtures, a simple screw-in socket adapter can make testing much easier.
• Environmental Factors: In some older or complex wiring systems, interference might occur. Try scanning multiple times or from slightly different angles.

9. Warranty and Support

For warranty information, technical support, or service inquiries, please contact the manufacturer or your point of purchase. Keep your purchase receipt as proof of purchase.