Most electrical wires incorporate copper or aluminium metal conductors.
Electrical wire (or cable) is an insulated piece of wire that is used to transport electricity. Copper is most often used in household electrical wiring, while aluminium wiring is widely used in commercial buildings and industrial settings on account of its lighter weight. This allows for smaller, cheaper cables (i.e., less copper per length of cable) but at the cost of slightly higher resistance losses due to increased cable length for a given transmission distance/power throughput. Wires are described by their type, size, shape, voltage rating, current rating, etc. A common analogy explains that you can use pipes to transport water (current), while wires are used to transport energy (voltage). In contrast to a solid core wire, electrical wire typically consists of a number of thin strands in the core surrounded by a flexible insulating layer. In order for power to be transferred from one end of the wire to the other, it is necessary that each strand be electrically connected (or "wet") through an outer coating or insulation. A variety of materials are used for insulation, such as rubber and plastic-based materials; these require extra processing during manufacturing. Cables with two or more conductors twisted together are described as "twisted pair" cables; individual wires within twisted pair cable are twisted together to form transverse pairs (TX and TX), which reduce electromagnetic interference (EMI). Cables with many individual insulated conductors are described as multi-stranded or jacketed.
An electric wire comprises conductors, which are usually made of metals that have low electrical resistance. Insulating materials, known as insulation or sheathing, surround the conductors to prevent them from contacting each other or short-circuiting. An insulated wire is covered with plastic or rubber material sheathing. Commonly used wire types include solid core wire, stranded wire, braided wire, foil, and magnet wire. A typical wiring system has three electrical wires. The hot wire carries the circuit voltage from the generating station to the house or place of use. The neutral wire returns the voltage to the source, thus completing the circuit. The ground wire maintains the charge balance in the circuit. Power surges are channelled away via the grounding wire. PVC (polyvinyl chloride) is the most widely used insulating sheath in household wiring is PVC (polyvinyl chloride). However, many industrial applications use rubber for its excellent flexibility, even at sub-freezing temperatures. Rubber's insulation properties are not very good compared to plastics like PVC, but rubber has superior flexibility resulting in much lower electric resistance.
A bare wire transmitting power is dangerous to touch. It's for this reason that an electrical cable must be insulated. Wires for household use are supplied as a non metallic sheathed cable (NM cable). The non metallic sheathed cables have 3 or more wires inside a flexible plastic jacket. Each wire, hot, neutral, and the third wire (where applicable), are insulated separately. The bare copper wire, which is the ground runs alongside the other two (or three) insulated conductors, and the outer sheath provides its insulation. Double insulation is achieved by adding the non metallic sheath to house these two to four wires. In many configurations of the NM cables, the hot wires and the neutral wires are both insulated, with the insulation of the bare ground wire being provided by the outer sheath.
An electric wire is manufactured by pulling a piece of copper or aluminium through a die to form the wire. The metal strip goes through the same process again to make many thin metal strands. These strands are then twisted together into groups, typically in three for power cables. For example, A/C current travels on wires composed of three strands twisted into one cable. A group of three insulated copper wires may be stranded for strength, with an outer coating to provide added protection against abrasion and environmental conditions such as moisture or extreme temperatures. Core wires are often made up of fine, high-conductivity copper filaments braided around thicker conductors that support increased ampacity or mechanical strength.
A conductor is a material that allows electricity to flow through it easily and freely; most metals are good conductors of electricity because they contain mobile electrons. Electricity can be carried by conduction, convection, or radiation (radiant energy transfer). Conduction is the primary method of transferring electrical energy from place to place when using metal wires or cables.
Insulators are materials that have very few free moving electrons, so electricity cannot flow through them well. Insulating materials include glass, rubber, ceramic and plastic insulation for wires. Special insulating materials called dielectrics are used to insulate electrical components, wires, and cables.
Electrical cables are designed to suit the conditions in which they are being used. The National Electrical Code (NEC) regulates the type of wires and cables used and the fundamental installation for a particular purpose for any given electrical project. At the state level, the Local Building Codes are implemented with reference to the codes provided by NEC.
The conventional NM cable is for use in dry residential wiring conditions. In exterior and wet conditions like underground electrical power lines or powered irrigation systems, the insulation used in NM cables is not sufficient.
For lightweight outdoor power needs such as outdoor garden shed lighting, the underground feeder cables (UF cables), a type of NM cable can be used.
Direct buried cable power wiring systems utilize more robust cable sheathing technology and a different wire configuration. Panel feed wires connect the main feeder wires (transmission lines) and the household switchboard or junction box. Since they are exposed to everyday weather conditions, their insulation is also enhanced compared to internal cables.Electrical wire comes in many types, each one designed to handle specific conditions. The two major types of electrical wire are stranded, and solid core; both come in many sub-types depending on the material used to make the wire, whether it is insulated or not, and other factors.
Solid core electrical wire has no insulation making it easy to identify because it can be seen running through walls and ceilings, creating power lines. However, metal conduits must be used with this type of wiring because bare conductors provide a pathway for humans as well as rodents.
Stranded wires have a number of thin strands twisted together instead of being composed of a single piece of metal. This makes them more flexible than solid wires, which can be advantageous when pulling wire through walls or installing it. Stranded wire insulation is also more flexible than solid-core, so it wears better over time, making stranded perfect for outdoor applications.
The wire gauge is the diameter of an electrical conductor. This parameter determines the amount of current power conductors can handle.
Wire sizes are outlined in the IEC 60228 standard of the International Electrotechnical Commission. The American Wire Gauge guidelines are used in the USA and the North American zone.
Wire gauge range from about No. 22 to No. 0000, although larger numbers do not necessarily mean higher capacity because more strands can be packed into the same-sized wire. Smaller wires have more surface area and therefore carry more current per square inch than larger wires of the same material and type. Take a look at this guide from the New South Wales government for tips on staying safe around electricity.Communication cables are conducting wires used for communication signal transmission. They are useful in transferring data, information, or a signal between two or more electronic devices or between components within a device.
A well known, widely used type is the coaxial cable. At the centre of a coaxial cable is the inner conductor surrounded by the tubular insulating layer. This layer is then covered with a braided copper mesh wire or a tubular conducting shield. The outer layer is a plastic jacket.
In conjunction with the twin lead cable, coaxial cables are widely used to transmit radio and cable TV signals and between antenna transmitters and receivers.The coaxial cable technology is being slowly replaced by other methods such as HDMI and UTP cables used in ethernet communication. The coaxial cable technology is also being phased out by wireless transmission.
Modern digital appliances utilise the ribbon cable type to transmit low voltages through the PCB and assist in signal transmission.