Jeremy: Hi! I am Jeremy from Klein Tools. Today I am going to show you how to properly use a Non-Contact Voltage Tester. Whether trying to install a ceiling fan, a new light fixture, or even a thermostat, you always want to ensure that the wires are not live before commencing any work. Thats where a Non-Contact Voltage Tester comes in. A voltage tester is a device that senses the electrical field generated by voltage on a wire or other electrical system to tell if the wire or system is energized with an electrical potential. When sensing voltage in dark cabinets, panels or rooms, a flashlight is normally required in addition to a Non-Contact Voltage Tester. There are Non-Contact Voltage Testers on the market, like this one, that come with a flashlight for this reason. Non-Contact Voltage Testers with flashlights can be found at Big Box Home Improvement Stores, online retailers or any trusted electrical distributor. Before beginning any work make sure you read, understand and follow all warnings and instructions in the manual so you are familiar with how to properly use the tester. Best practice in testing with Non-Contact Voltage Testers consists of three steps:First, test a known live system, such as a cord of a lit lamp or an electrical receptacle or outlet to verify the tester is functioning correctly. Then test the unknown system. And then finally, repeat the test on a known live system. When the Non-Contact Testers detect the presence of a voltage, various models may provide continuous trips or you may see a series of flashes or both to confirm the tester has detected voltage. It is important to test each wire before and after disconnecting it to ensure it is not energized. When testing an electrical outlet or receptacle, the tip just needs to be placed on the faceplate near the smaller plug slot. But its a good idea to test all slots on the outlet or receptacle just in case they were wired incorrectly, differently or on different circuits. If the receptacle is connected to a wall switch, make sure the switch is on during testing. When testing a power switch, unscrew and remove the cover plate, then place the nose of the tester against the screw terminals on the side of the switch. When testing a three-way switch, test all screw terminals on both switches before proceeding. When testing a light fixture, turn the circuit off at the main panel and ensure the light switch is turned on. Then unscrew the light bulb and place the nose of the tester onto the center socket button. If the light fixture has two switches, as with a three-way switch, test with one switch in both the up and down position. Having a Non-Contact Voltage Tester in your toolbox can save a lot of time when testing to ensure that a workplace is safe every time.