Wires that are white or gray are neutrally charged. Neutral wires, on the other hand, can transport power and represent a risk of electrocution if not handled appropriately. Power is returned to the service panel through white and gray cables. If not handled appropriately, both hot and neutral wires have the ability to shock and hurt you. To protect yourself from electrical shock, never touch any metal object to any part of your body, including hair, without first knowing that it is safe to do so. This includes appliances such as lamps and telephones that are connected to circuits containing metal objects.
Electricity always takes the path of least resistance. That means that if there's a ground path available, electricity will use that route to reach the ground. If not, it'll find another way. For example, if you're working with live electricity and don't have a good path to ground, you could be given an electric shock.
The voltage difference between ordinary household wiring (120 volts) and power line voltage (240-400 volts) can be dangerous if not done properly. If you try to connect a load to power line voltage without special protection, you may get a high voltage spark or arc between the wires at each end of the connection, which could start a fire or cause other damage. This is called "energizing" the circuit, and it should only be done by a professional electrician.
A neutral wire is indicated by the colors white and gray. That is, it connects to the neutral bus bar of an electrical panel. The black wire in a house is the hot wire; it always connects to a voltage source. The term "hot" means powerful or significant.
The purpose of the neutral conductor is to carry current from one end of the network to the other, just like any other conductor would do. But because electricity can't flow through a neutral, this conductor has no function except as a safety measure. If a leg of the network becomes damaged so that electricity cannot reach it, then the neutral will not be able to carry current there either, so another part of the network will have to replace it.
Neutral conductors are required by law in some states. They must be present in all new construction and all remodels. Any conductor that carries current whenever there is a power failure is considered to be a neutral conductor. Old wiring sometimes contains neutrals, but they are usually made of aluminum or copper and therefore colorless. These old neutrals don't provide much protection against electric shock and should be replaced before you begin any work on your house.
Wires for electricity 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. If you were to connect both wires together with a voltmeter, it would read 120 volts.
The term "wiring system" refers to the arrangement of cables and wiring devices within a building or home. In an electrical system, all wiring devices are hot-wired to the breaker panel. Neutral conductors are not wired to wall plates or other wiring devices. They may be marked with blue tape to indicate their neutral status.
In a wiring system, each piece of cable being fed into a junction box is called a branch. Each terminal in the junction box is also called a branch. Multiple branches can be tied together inside the box using what's called a load center. This helps prevent individuals from connecting two separate loads to one circuit, which could cause an overload on either service.
Electricity is transmitted to homes and businesses by means of transmission lines. Two types of transmission lines are used for distributing electricity: high-voltage transmission lines and low-voltage distribution lines. High-voltage transmission lines carry large amounts of electricity over long distances; they're used primarily by electric power companies to transmit electricity from one part of the country to another.
White. Depending on the kind of circuit, the "common" wire is the "neutral" or "ground" wire. A black "hot" wire, a white "neutral" or "common" wire, and a green or bare "ground" wire are standard in US home wiring. The terms "hot", "neutral", and "ground" are taken from the fact that these wires are used to supply power, send signals, and conduct electricity to ground, respectively.
The term "wiring scheme" is used to describe the arrangement of circuits inside a building or house. In many buildings today, all the circuits inside will use either red, black, or white wires to connect them together. However, this was not always the case. Before 1963, electrical wiring within homes and businesses was done with "composite" cable. This included several types of cables which were all called "composite" because they were made from multiple strands of wire wrapped around a core. These cables were color-coded according to which strand was used for voltage and which was used for current. So, for example, a red-white-red-black-black-black cable would have a red core, a white insulation cover, a red second layer, a black third layer, and a black jacket.
In most cases, the neutral and ground wires are also white.
The white cable is the positive data wire. Green: The green wire is used for data as well, but it is the negative wire. The plus and minus symbols on wiring diagrams indicate whether each wire is intended to be connected to another conductor or to a circuit element such as a fuse or switch. In other words, black means ground.
For example, in a three-wire plug that fits into a standard outlet, the black wire is the ground pin. The red wire is the live pin. The white wire is the third pin, which is not connected to anything. It's called a "hot" wire because you should never connect it to anything else than a hot source - in this case, the light bulb. If you do so, you could cause electrical damage to your house if the power goes out when the light bulb burns out.
The direction of the line patterns on a wiring diagram will tell you what connection is made at each terminal. For example, if the pattern on a wire is the same size as the others (all the way around) then it is likely to be the + signified by the presence of a black circle above it. If one end is larger than the other, then it is the - sign indicated by a white circle instead.
Only white (or grey) for the neutral power wire and bare copper, green, or green with a yellow stripe for the protective ground are required by the US National Electrical Code. In theory, any color other than these may be used for the power wires. In practice, only red for voltage and black for current are used, so all other colors represent an optional safety feature.
The code requires that if you're going to use three conductors to carry single-phase 240-volt current, then they must be identified as hot, hot, neutral, or neutral, neutral. But it also allows you to use four conductors to carry single-phase 120-volt current - call them line 1, line 2, third line 3, and fourth line 4 - if you identify line 1 and line 2, and then identify third line 3 and fourth line 4. So in this case the code permits you to use any two colors of your choice for lines 1 and 2, and any other two colors for lines 3 and 4.
But it's best not to split up the currents like this because it gives each conductor a chance to fail without warning. Instead, always use the same color for all four conductors. This makes it easier to connect them up safely when installing new wiring or repairing old wiring.
The color coding helps professionals understand which parts of the circuit need attention first when doing maintenance or repair work.