Hanging a shelf seems like a simple task, but there is an unknown danger that lurks beneath your wall's surface: electrical wiring. Due to safety reasons and the unsightly appearance of electrical wiring, electricians run the wires behind the walls and through the studs. Locating the wires is a simple task when using either a handheld wall scanner (a.k.a. multiscanner) or stud finder with wire detection. These particular tools trace the electricity flowing through the wire. A visual or audio signal will be emitted from the unit to tell you where your wires are located.
Turn on the wall scanner. Push the "Battery Charge Function" button to check if the batteries need replacing. Low battery power may cause an inaccurate reading. Two ways that indicate low battery life are an LED indicator showing low battery power, or an audible signal such as a beep when the unit is switched on. If this is the first time you are using the unit, insert batteries per the manufacturer's instructions. Replace the batteries if a low battery power is indicated.
Set the scanner to detect wiring, as applicable for the tool. Place the scanner on the wall where you want to hang your shelf. Hold the unit with the head flush against the wall. Move the head back and forth slowly over the area. Listen for a beep or watch the indicator arm for a positive movement for electricity. Read your manufacturer's instructions on exactly what your cable detector will do when electrical wires are found, if you are unsure.
Hang your shelf from the wall if no indicators exist for electrical wires. If a positive is shown for electrical wiring, choose a different location for hanging your shelf, one that is free of electrical wires.