How to Find and Trace Electrical Wires in Walls

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Simple ways to trace and locate electrical wires before you drill

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Using a Stud Finder

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Using a Wire Tracer or Locator

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Testing for Live Wires

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Before drilling into a wall in your home, it’s vital to identify any electrical components to avoid electrocution or damaging your wiring. Thankfully, it’s a simple safety precaution that takes just minutes. We’ll show you how to find wires in your walls using both a stud finder and a wire tracer. Then, we’ll show you how to determine if the wire is live, so you can stay safe and get the job done right.

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Move a stud finder capable of detecting electric currents slowly along the wall, and mark the spots where it beeps in pencil.
Or, use a wire tracer for a more reliable reading. Attach the tracer’s wires to the end of an exposed wire, then turn on both the transmitter and receiver.
Then, move the tracer’s transmitter slowly along the wall, marking the spots where it beeps with pencil or tape.

Method 1

Method 1 of 3:

Using a Stud Finder

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Stud finders put out a magnetic field to detect changes in density, and some also detect metal objects or electrical currents.

To use a stud finder, hold it to the wall and move it slowly back and forth until you hear it beep, indicating that there’s an object. As you work, lightly mark any spot the stud finder detects, so that you know to avoid it in the future.

Note that since stud finders detect many objects, it may beep for something other than a wire, so this method works best if you’re just trying to find out where not to drill.

Check the stud finder’s packaging or user manual to ensure that it can detect electrical currents as well as density.

Wire detectors are similar to stud finders, but are specialized to search for wires. Their operation is often identical.

Method 2

Method 2 of 3:

Using a Wire Tracer or Locator

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To be safe, turn off your circuit breaker to ensure that power isn’t running through the wires, which can cause electrocution.^{[1]XResearch source} Find your home’s circuit breaker and set the switches for the relevant areas to “off.”
Check the manufacturer’s instructions to find a way to plug in and connect your wire tracer to the electrical circuit. If a cable is sticking out of the wall, choose a connector bit that will plug into the cable. If your device comes with a traditional electrical plug, connect it to a socket at the base of the wall.

If your device has clamps, attach the red clamp to a visible wire, and the green clamp to a nearby metallic object, like a pipe.^{[2]XResearch source}The transmitter is often larger than the receiver, which is usually thinner and smaller with a pointed tip on one end.
Power on both the transmitter and receiver. Place the pointed end of the receiver against the wall and move it slowly back and forth, horizontally or vertically.

When the receiver detects an electrical current or a wire, it’ll beep to let you know.^{[3]XResearch source}

Test the receiver on a spot where you know there are wires, like an outlet. Listen for the beep to ensure it’s working correctly.

Adjust the tracer’s sensitivity until the signal strength is between 50% and 75%. Once the signal bar on your receiver is fully expanded, you’ve found your wire.^{[4]XResearch source}
If possible, insert your transmitter’s remote lead (a cord with a single prong) into an electrical socket of a different wall. This boosts the signal and makes wires easier to find.^{[5]XResearch source} Avoid plugging both ends of the remote lead into sockets attached to the same wall. Some wire tracers are also equipped with a tone generator that emits different sounds for different wires, allowing you to trace individual wires within a bundle.
Continue dragging the device slowly along the wall.^{[6]XResearch source} Any time it beeps and finds a wire, lightly mark the spot with a pencil or bit of tape. Continue following the beeps to trace the wire to its opposite terminal.

Method 3

Method 3 of 3:

Testing for Live Wires with a Voltage Tester

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Or, touch the tip of the detector to the outlet where the wire originates. If the detector makes a sound and lights up, the wire is live, so practice caution.^{[7]XResearch source}A wireless detector can sometimes give phantom readings, so always follow up with a contact tester.
Contact testers, or multimeters, have 2 prongs. Use the multimeter by placing either prong into the slots of an outlet. The multimeter then tells you if the outlet, and therefore its wires, have a charge, by lighting up.^{[8]XResearch source}A plug-in tester works similarly, but in the form of a wall plug.

Expert Q&A

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Question
When a fuse is broken, what does it read on a multimeter?
Ricardo Mitchell
Electrician & Construction Professional, CN Coterie
Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience.
Ricardo Mitchell
Electrician & Construction Professional, CN Coterie
Expert Answer
When a fuse is broken, it reads the circuit is not complete, so it reads an open line on the multimeter.
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Tips

In a pinch, a metal detector can also be used to discover wires within walls, though they may not be very precise.^{[9]XResearch source}
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If they’re available, your home’s blueprints might also display the networks and positioning of its original wiring.
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Warnings

Always wear insulated electrical gloves when handling exposed wires.^{[10]XTrustworthy SourceUS Occupational Safety and Health AdministrationU.S. government agency responsible for setting and enforcing workplace safety standardsGo to source}
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If you’re ever in doubt about the quality or electrical status of a wire, consult a professional electrician.
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