Why is my StudSensor™ tool's AC alert light always on? It's showing live wires everywhere.
There are three possible causes that can make the WireWarning® detection to give a large area of false positive readings:
- Static electricity on the wall
- Fingers moved after calibration
- Lots of strong wires behind wall
Static electricity: If the WireWarning® detection icon or light comes on when you move the tool and turns off when you stop moving it, static electricity is usually the cause. If you're scanning in a low humidity environment on certain surfaces, the felt pad on the back of your tool rubs against the wall and generates static electricity. While there's nothing you can do to stop the static electricity from forming, you can still get accurate readings by just paying attention to what the tool indicates when it's not moving. If you're holding the tool still and the WireWarning® detection is still on, then there is a live wire in the vicinity.
Movement of fingers or touching the wall: The human body can dissipate electrical charges, so if your fingers touch the wall during calibration, the sensors might calibrate incorrectly. The tool reads the electrical field around it when it calibrates, and this reading includes ambient electrical signals from the wall and from your hand. Moving your hand or fingers after calibration can cause the sensors to pick up a different electrical reading.
Multiple or strong wires: There are possibly one or several wires right behind the wall giving off a very strong signal, so the tool detects electricity many inches away on all sides from the actual wire(s). If the WireWarning® detection indicates an oversized area, you can narrow the results down by recalibrating the tool closer to the wire. Mark the wall where the WireWarning® detection first turns on, place the tool over that mark, and turn it back on. The tool will re-calibrate itself closer to the wire, so it will now be more selective about what it finds and detect the live wire within a smaller area.
Please note that the WireWarning® detection is not precise enough to pinpoint or trace the actual location of the wire. Instead, its purpose is to warn of the potential existence of a live, unshielded AC wire. If you need to locate and trace the live, unshielded AC wire, you would instead use one of our MultiScanner® tools with AC scanning capabilities.
*Note: In some buildings, wires are shielded by metal conduit. Neither the WireWarning® detection or AC Scanning feature can detect live wires shielded by metal. If you suspect you have shielded wires, use a metal scanning tool.
CAUTION: While power must be on in order to detect live wires, you should always turn the power off before working near electrical wires.
