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Electrical cable

technology Maturity 11-13 Next article →

An electrical cable is a specialized assembly of one or more wires. These wires run side by side or are bundled together. The primary purpose of a cable is to act as an electrical conductor. This allows it to carry electric current from one place to another.

Leitungsende Abisoliert en
Leitungsende Abisoliert en

Cables connect two or more devices. They enable the transfer of electrical signals, power, or both. Without these connections, modern technology could not function. They are essential for everything from small gadgets to massive power grids.

Physically, a cable is composed of several specific layers. It starts with one or more conductors, which are the wires that carry the electricity. Each conductor has its own insulation to keep the current contained. Some cables also include optional screens or individual coverings. An assembly protection and a final protective covering are often added to the outside.

Electric guide 3×2.5 mm
Electric guide 3×2.5 mm

In some cases, cables are formed into a larger cable assembly. These can be used to connect many terminals together in a cable tree or harness.

Engineers use different methods to change how a cable behaves. To make a cable more flexible, they use a process called stranding. In stranding, many small individual wires are twisted or braided together. This creates a larger wire that bends more easily than a single solid wire. Bunching small wires before concentric stranding provides the most flexibility.

ElectricWireOnReel
ElectricWireOnReel

The copper wires inside may also be plated with other metals. Metals like tin, gold, or silver are used because they resist oxidation. Tinning also provides lubrication between the strands and makes soldering easier.

History shows how materials for cables have changed over time. In the 19th and early 20th centuries, makers used cloth, rubber, or paper for insulation. For underwater cables in the 19th century, a natural latex called gutta-percha was used. In 1930, the first man-made plastic, polyethylene, was invented. It was initially restricted to military use. After World War 2, it became more widely available. During the war, a telegraph cable using polyethylene was laid across the English Channel to support troops after D-Day.

Cables must also manage electromagnetic fields. Every current-carrying conductor radiates an electromagnetic field. At the same time, a cable can pick up energy from nearby fields. This can cause unwanted energy transmission or pick up noise that masks a signal.

Coaxial cable cutaway
Coaxial cable cutaway

To solve this, engineers use three main design techniques. The first is shielding, which uses a foil or wire mesh to create a Faraday cage. This decouples the wires from external electrical fields. The second is coaxial geometry, where the inner conductor sits exactly in the center of a circular shield. The third is twisted-pair geometry, where two wires are wound around each other to cancel out interference.

USB Twisted Pair
USB Twisted Pair

Safety is a critical concern because many cable jackets are made of flexible plastic. This material can burn, which creates a fire hazard when cables are grouped together.

Cable tray fire sweden
Cable tray fire sweden

To prevent this, manufacturers can formulate the jacketing material to resist fire. They can also apply fire retardant coatings directly to the cable exterior. Another method is to place the cables inside boxes made of noncombustible materials. This helps isolate the threat and prevents a fire from spreading through an installation.

There are many different types of cables designed for specific tasks. Power cables are used for the bulk transmission of alternating and direct current. These often use high-voltage to move electricity over long distances. Coaxial cables are used for radio frequency signals, such as cable television. Ribbon cables are designed to handle low-level voltages and are useful when many wires are needed. Other specialized types include armored cable for strength and submersible cables for use underwater. These various designs ensure that electricity and data reach their destinations safely and efficiently.

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🖼️ Images & Media (8)
File:Leitungsende Abisoliert en.svg
Leitungsende Abisoliert en.svg
File:Electric guide 3×2.5 mm.jpg
Electric guide 3×2.5 mm.jpg
File:6 inch cable.jpg
6 inch cable.jpg
File:Cable tray fire sweden.jpg
Cable tray fire sweden.jpg
File:500mcm cable jacket marking.jpg
500mcm cable jacket marking.jpg
File:Coaxial cable cutaway.svg
Coaxial cable cutaway.svg
File:USB Twisted Pair.svg
USB Twisted Pair.svg
File:ElectricWireOnReel.JPG
ElectricWireOnReel.JPG
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