A white wire serves as the "neutral," while a bare copper wire serves as the ground wire. When connecting electrical lines, the black wires must be connected, the white wires must be connected to the white wires, and the ground wires must be connected. If one of these connections is made incorrectly, it can lead to electric shock or damage to your property. Before you connect any wires, be sure that you have the correct number of wires coming from the outlet box or fuse panel. If in doubt, contact a licensed wiring professional.
Copper is a good conductor, which means it will help the electricity flow if it's there. But other things can cause electricity to flow in copper wires, such as oxidation or moisture from rain or melted snow. These things can be removed with acid or soda water, respectively. After cleaning, re-insulate if necessary. Then connect the wires together with secure splices. You can use wire connectors, cable ties, or tape.
The term "copper" when used to describe a wire is referring to its material composition, not its color. Even if a wire is only hot before you start working with it, by the time you are finished it will be both hot and neutral. The fact that it was once hot does not mean that it will stay hot.
Color-Coding of Basic Wires On electrical equipment, a black or red-hot wire is commonly connected to a brass-colored screw terminal or a black wire lead. Typically, a white neutral wire connects to a silver-colored termination or white wire lead. The term "hot" means that this conductor is used to carry a voltage above ground level. The term "neutral" means that this conductor is used to carry current without affecting any other circuits or devices.
The connection between a black wire and a silver-colored screw terminal will not damage either metal if made properly. However, connection between a red-hot wire and a silver-colored screw terminal could cause injury because the heat from the wire could burn someone who touches it. Be sure that you do not connect a hot wire to a silver-colored screw terminal. If in doubt, use a black wire instead.
Connection between a black wire and a gold-colored screw terminal will not damage either metal if made properly. However, connection between a red-hot wire and a gold-colored screw terminal could cause injury because the heat from the wire could burn someone who touches it. Gold does conduct electricity so this connection should be made only with care. Use a black wire instead.
Connection between a white wire and a gold-colored screw terminal will not damage either metal if made properly.
In most circumstances, the common wire will be linked to either the supply (from the breaker) or the load. If you check inside the box, you should see a neutral (white) and a hot (black) wire from the same cable. Normally, the white wire would be linked to other white wires, however in this situation, the black wire is common. The black wire can be any of the others if there are not too many cables running into the box, so it's best to just connect it to something to avoid damaging other wires.
If you look at the wiring diagram for your house, you should be able to identify which black wire is common. Sometimes they are called "third" or "fourth" wires because they are used as secondary connections if one of the other wires gets damaged. For example, if you had an open switch for several years and then closed it recently, the old copper wire inside the wall could be damaged and only work properly with the new switch installed properly. In this case, the old switch controlled two blacks and one white, while the new one controls four blacks.
The common black wire is always connected to the chassis of your home or building, while the neutral white wire is always connected to a metal part of the structure. Chances are good that if you can get access to one of these wires, they will be fine to use when installing lights, appliances, and other things that require electricity.
The black (hot) wire is connected to the brass screw or a hole on the rear of the device on the same side as the brass screw. This wire is occasionally red. Typically, a white neutral wire connects to a silver-colored terminal or a white wire lead....
We know what each wire color performs in the circuit. The black wire is the "hot" wire, carrying power from the breaker panel to the switch or light source. The white wire serves as the "neutral" line, carrying any wasted power and current back to the breaker panel. A green wire may be included as a third conductor, called a "ground" wire. It can conduct electricity even if you have metal fillings in your teeth or other objects that would block other wires. This information will help you identify which wires are which when you get into more complicated wiring situations.
Here's how you determine which is hot and which is neutral: If you were to cut one of the wires, it would cause the light to go out. That means the un-cut wire must be neutral and the cut wire must be hot. You could also use your multimeter to check which wire has the higher voltage. If there was no voltage on either wire, they would both read 0 volts. But if one was live and one was not, then you would see a difference between them. Live wires have a voltage around 120 volts, while dead wires do not.
Finally, if you were to connect one end of a voltmeter to a live wire and another end to the opposite live wire, you would see a reading on the meter. This shows that there is electrical energy flowing through that portion of the cable.