WiremanWireman · Trace and identify a circuit: troubleshooting for electricians · 2023 NEC ·
Trace and identify a circuit
Find the breaker, follow a cable through walls, or ring out one conductor in a bundle.
Before you start
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How it works
A circuit tracer has two parts: a transmitter that puts a signal on the wiring, and a receiver that beeps louder as it gets closer to the wire carrying it. Some work on live circuits through a receptacle; others need the circuit dead and connect to the conductor directly. Ringing out uses the meter’s continuity beep: tie the far end of a conductor to a known point, then find the one that beeps at the near end.
Every question and answer in this guide. Tap “Step by step” to walk through it.
- What are you trying to do?
- Find which breaker feeds somethingTest: Use a breaker finder
- One breaker is clearly strongestTest: Turn it off and confirmExpect: 0 V with that breaker off.
- Reads 0 VBreaker identified
- Still liveNot that breaker, or more than one source
- Several breakers read about the sameThe signal is spreading
- One breaker is clearly strongestTest: Turn it off and confirmExpect: 0 V with that breaker off.
- Follow a cable through walls or undergroundTest: Trace a dead cable
- Follows clearly to a box or the endCable path traced
- Fades out partway alongOpen conductor or a hidden splice
- Identify one conductor in a bundleTest: Ring out the conductorExpect: A beep on the one conductor you tied off, and silence on the rest.
- Beeps on exactly oneConductor identified
- Beeps on severalConductors connected together somewhere
- Beeps on noneOpen conductor or a hidden splice
- Find which breaker feeds somethingTest: Use a breaker finder