How to Test if an Electrical Cable is Live

Working with electrical cable is not a job you should take lightly. It can be dangerous. It can be confusing when you're dealing with a box of jumbled wires. If you didn't originally do the work, you have to rely on the expertise of someone else. If you begin working with the electrical system in your home, you may find yourself with a tiny shock or, at worse, death. You should turn off the electricity before you begin such work, unless you need to know which wire is live or hot before turning it off. This article will show you how to determine which electrical cable is live.

Step 1 - Know the Standards

Home wiring has to be up to code and, as such, the wires you find inside an electrical box are color-coded. This does not mean that someone did not come along and change things around in a repair attempt and, in the process, use a different color of wire. Thus it is smart to know the standards but even smarter to not take their word for it.

In home wiring, the black wire is the live wire. The black wire is what you should find attached to the spade or brass terminal. The green wire is typically the ground wire. The ground wire provides another path for the electricity to travel. It is there to save your life. Sometimes the ground wire is also yellow or has a yellow stripe. Make sure the ground wire is attached correctly during an electrical job. The neutral wire is the white wire. Circuits are only made when there is a complete path for the current to flow. This wire should be connected to the wider space or the silver terminal. Some outlets will have what is known as a traveler wire that is red. This can connect a three-way switch.

Step 2 - Gain Access to the Electrical Cable

Use the screwdriver to remove the face plate or the box cover. Make sure you do not touch any wires with the screwdriver and that you are grounded with the wrist strap. You don't need to remove wires in order to test them for current, so do not try to touch them.

Step 3 - Test the Electrical Cable for Current

You can use either the current tester or the voltage meter to determine if an electrical cable is hot. Keep in mind that it is possible for more than wire to be live. Touch the tip of the meter or tester to the screw where the wires are attached. Go slowly and keep your eyes and ears open. When current is found, the light will go on and the machine will beep. When you are testing, be sure to test between the wires as well. If current is flowing between two wires, the voltage meter will read 0.