How to Find and Trace a Circuit Using a Circuit Breaker Finder

A Sperry circuit finder in an outlet
  • 01 of 06

    How to Use an Electronic Circuit Breaker Finder

    Electronic circuit finder being used in an electrical panel

    Circuit breakers are very convenient and common safety devices used to protect your electrical system from overloading the circuit wires. Unless your circuit breaker box is very carefully mapped, though, it can be difficult to identify which breaker controls which outlets, switches, or light fixtures. 

    When an overload or short circuit "trips" a  circuit breaker, it easy to identify, as the lever on the breaker snaps to the "off" position. But when you are doing home repair work and just want to turn off a circuit feeding an electrical outlet or light fixture, finding the correct circuit breaker to turn off is usually a two-person job involving you at the circuit breaker box, an assistant at the outlet, and a good deal of shouting back and forth.

    A great little device that simplifies this task is an electronic Circuit Breaker Finder, which easily locates a circuit in an electrical power panel or load center and makes this all a one-person job. These devices work for either circuit breakers or fuses. Let's take a look.

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  • 02 of 06

    How the Circuit Breaker Finder Works

    A circuit breaker finder

    The electronic circuit breaker finder works with two parts: a transmitter and a receiver. The transmitter plugs into the outlet or light socket for which you're trying to identify the controlling circuit breaker or fuse. 

    At the electrical service panel, you use the electronic receiver that is paired with the transmitter. When the receiver passes over over the circuit and circuit breaker carrying the electronic signal from the transmitter, the receiver rapidly beeps and flashes. It's as simple as that. 

    There are many manufacturers of these devices. The one used in this tutorial is Model Sperry Instruments CS500A. 

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  • 03 of 06

    Battery Installation

    A circuit breaker finder receiver on/off switch

    The receiver will usually be powered by a 9-volt battery or similar. The model used in this tutorial has a 9-volt battery installed in the handle and is easily accessed by sliding a cover back on the bottom of the receiver.

    Once the battery is installed, confirm operation by rotating the wheel back until it just clicks and the LED lights up. The unit is now at maximum sensitivity. You will adjust the sensitivity of the unit when you are at the electrical panel.

    The next step is to test the transmitter and receiver operation.

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  • 04 of 06

    Test Receiver and Transmitter

    A circuit breaker finder

    Next, test that the receiver will pick up the transmitter's signal. Place the receiver near the transmitter as shown in the above photo. You will get a distinctive beep occurring about six times per second, and the LED will flash if the receiver is working and the wall outlet’s power is on.

    Once you have confirmed the transmitter and receiver are working, you can now use the device to locate the matching circuit breaker in your panel.

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  • 05 of 06

    Match Circuit to Circuit Breaker

    Diagram of a circuit breaker finder in action

    Once you have confirmed operation of the transmitter and receiver, now you're ready to the circuit breaker finder: 

    1. Plug the electronic transmitter into the desired wall outlet, making sure the power to the outlet is on.
    2. At the circuit breaker panel or fuse box, hold the receiver, so the flat surface of the tapered end is at a right angle and directly on the face of the circuit breaker or fuse, as shown in the photo.
    3. Slowly move the receiver up and down over the row or rows of circuit breakers or fuses while continually lowering the receiver’s sensitivity by rotating the wheel away from the panel box until only one breaker or fuse causes the receiver to beep. (Note: Sometimes an adjacent breaker or fuse may cause a beep due to the routing of the wires in the panel.)
    4. After you have located the correct breaker or fuse, you can turn off the circuit, and the receiver will stop beeping.
    5. It is a good idea also to check to make sure the red light on the transmitter in the outlet is off, which confirms you have turned off the correct breaker or fuse.
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  • 06 of 06

    Matching a Lighting Circuit to Circuit Breaker

    A diagram with a circuit breaker finder and socket adapter

    If you have a light fixture that is not attached to an outlet—a ceiling fixture, for example—you may be able to use a neat little adapter called a keyless socket adapter. It works by simply being screwed into the threaded base of a light fixture socket,  which is thereby converted to a non-grounded outlet plug.

    Simply plug the transmitter into the adapter, and it will function as if it were plugged into an outlet.

    Follow the same instructions as in Step 5 of this tutorial to trace this lighting circuit back to the correct circuit breaker in your panel.