Wireman · Can’t find which breaker feeds something: troubleshooting for electricians · 2023 NEC ·

Can’t find which breaker feeds something

Use the directory, a breaker finder or the one-at-a-time method, and know what it means when nothing turns it off.

Before you start

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How it works

Each branch circuit starts at one breaker, but panel labels are often missing or wrong after years of changes. A breaker finder sends a signal from an outlet that a handheld receiver picks up at the right breaker. For lights and hardwired items, turning breakers off one at a time works. A box can hold more than one circuit, and sometimes power comes from a second panel, so always confirm dead with a meter before working.

Step by stepFull flowchart

Every question and answer in this guide. Tap “Step by step” to walk through it.

What are you trying to find the breaker for?
- A receptacleTest: Use a breaker finder
  - Found it, and it kills the receptacleFound the breaker
  - Picked one, but the receptacle stays liveTest: Turn breakers off one at a time
    - One breaker kills itFound the breaker
    - Part dies, part stays liveMore than one circuit in the area or box
    - Stays live with every breaker offIs there another panel, a subpanel, a generator, solar or a second meter?
      - Yes, there’s another panel or sourceIt’s fed from another panel or source
      - None foundTest: Confirm with a meterExpect: 0 V if it’s truly dead.
        About 0 V: it’s deadIt was a false alarm from a non-contact tester
        About 120 V or morePower from an unknown source
  - No clear signalTest: Turn breakers off one at a time
    - One breaker kills itFound the breaker
    - Part dies, part stays liveMore than one circuit in the area or box
    - Stays live with every breaker offIs there another panel, a subpanel, a generator, solar or a second meter?
      - Yes, there’s another panel or sourceIt’s fed from another panel or source
      - None foundTest: Confirm with a meterExpect: 0 V if it’s truly dead.
        About 0 V: it’s deadIt was a false alarm from a non-contact tester
        About 120 V or morePower from an unknown source
- A light or hardwired itemDoes the panel directory list it, and does turning that breaker off kill it?
  - Yes, that breaker kills itFound the breaker
  - No label, or the label is wrongTest: Turn breakers off one at a time
    - One breaker kills itFound the breaker
    - Part dies, part stays liveMore than one circuit in the area or box
    - Stays live with every breaker offIs there another panel, a subpanel, a generator, solar or a second meter?
      - Yes, there’s another panel or sourceIt’s fed from another panel or source
      - None foundTest: Confirm with a meterExpect: 0 V if it’s truly dead.
        About 0 V: it’s deadIt was a false alarm from a non-contact tester
        About 120 V or morePower from an unknown source
- A whole room or several thingsDoes the panel directory list it, and does turning that breaker off kill it?
  - Yes, that breaker kills itFound the breaker
  - No label, or the label is wrongTest: Turn breakers off one at a time
    - One breaker kills itFound the breaker
    - Part dies, part stays liveMore than one circuit in the area or box
    - Stays live with every breaker offIs there another panel, a subpanel, a generator, solar or a second meter?
      - Yes, there’s another panel or sourceIt’s fed from another panel or source
      - None foundTest: Confirm with a meterExpect: 0 V if it’s truly dead.
        About 0 V: it’s deadIt was a false alarm from a non-contact tester
        About 120 V or morePower from an unknown source