3. Capacitive voltage detectors have certain limitations. Correct operation depends upon the capacitance between the detector's barrel and ground (normally through your hand and body). If this path is broken for any reason, the detector probably won't work. For example, if you're standing on a wooden ladder, the capacitance between your body and ground will be much less than if you were standing on a concrete floor. To help avoid incorrect detector readings, find an installation ground that you can touch when using the voltage detector. Remember, in a series circuit, the smaller the capacitance, the greater the voltage drop: there might be too much voltage drop from you to the floor and too little across the detector. The detectors will also have a certain minimum voltage to turn on. In our wooden ladder scenario, the detector might not turn on despite the circuit being hot. By similar reasoning, the detector cannot detect live conductors inside a grounded metal conduit.
