How are high-voltage cables made

Cable: construction, manufacture, application

electric wire consist of electrical or optical individual conductors (veins) that are connected with insulating material.

Synonym (s): cables, wires

Difference cable line

Cables and wires are used in information technology and electrical engineering. Both are used to supply electrical energy or to transport information. The terms are often incorrectly used synonymously. Cables are generally not visible, so they are located underground or on the sea floor. You can see lines on the other hand.

The following list shows when it is a cable and when it is not:

  • Electric power lines: Such power lines are e.g. the installation lines that are laid in houses to supply all rooms with electricity. They are connected to sockets, lamps, light switches, etc. These lines are usually hidden in the wall - so you could think that these are "power cables" - but since the lines become visible as soon as you connect them to a lamp, for example, we speak of lines here.
  • Aerial cables (self-supporting cables) are lines that are attached to masts and do not require any additional supports. They are used in the telecommunications sector, so cables on telephone poles are a good example of aerial cables. Since these lines are visible, the aerial cable should actually be called the aerial line.
  • Power lines (high-voltage lines) are among the overhead lines and are suspended from high-voltage pylons. With their help, energy can be transmitted over long distances.
  • Data, network and audio cables, all of these technologies should actually be called cables. Because they are all clearly visible.
  • Underground cables are located underground, so they are not visible and are therefore rightly called "cables". Their great advantage over free cables is that they are protected from the weather and "invisible" underground so that they do not disturb the environment. The disadvantage of underground cables is that they are harder to maintain and are often damaged if construction workers carelessly dig in places where underground cables have been laid.

Cables and wires in electrical engineering

A different definition prevails in electrical engineering. Cables are used here when they are permanently installed, i.e. not movable, while a line has to be flexible during operation. With this definition, it does not matter whether the cable / line is visible or not. In addition, in addition to electrical energy, gases, for example, can also flow through a line. When it comes to cables, we always mean electrical energy.

There is the DESINA standard for installing cables.

Construction cable

Simple construction of a cable

Depending on what function a cable / line has, the cable structure also differs. Usually two or more wires are joined together to form a cable. The cable casing (cable jacket) encloses and protects the individual wires. A core is a conductor (also wire) that is enclosed with an insulation. A conductor / wire is therefore always uninsulated, while a core is insulated. The insulation has a different color depending on the type of conductor. So you can see immediately from the color which conductor has to be connected where.

Cable types

Cable manufacture

How cables are made is explained by MEDI Kabel in the video

is a multi-stage process and consists of stranding, stranding, extrusion, winding, braiding and cable identification. Depending on your needs, some of these steps are repeated more often. Before each individual process, the cable must first be unwound from a reel. Then the processing follows and then it winds the bobbin again. This means that cable production does not result in an infinitely long cable that is simply cut off when necessary. Rather, a cable can only be as long as the coil is large. Depending on the length, you may need a larger coil. At some point, however, the maximum capacity will also be reached here.

Stranding & core extrusion

At the beginning, a stranding machine uses several thin copper wires to make a conductor, the so-called stranded wire. The strand is insulated with a sheath. Typical insulating materials are made of plastic, e.g. PE, PVC or PP. This process is called wire extrusion. After this step, one no longer speaks of a strand but of a wire.


Different stranded cores

A stranding system then strands individual cores together. The stranding is done by twisting the wires together. Depending on how many wires are stranded together, a different cable is created at the end. There are also different types of stranding. For example paired stranding, star-quadruple stranding and Dieselhorst-Martin quadruple stranding:

  • If the stranding machine twists two strands into a "double strand", it is a pair stranding.
  • The star-quad stranding consists of four cores that are joined together to form a large strand.
  • In the Dieselhorst-Martin four-strand stranding, two double strands are stranded together again. So a total of four wires are twisted here.

There is another reason for stranding: It is done so that the wires (and the cable / wire itself) are later robust, flexible and therefore suitable for energy chains. In this way, they are connected to form a compact, solid strand. To support this mobility, a machine sometimes wraps the stranded cores in foil or fleece. This process is called Wrapping or banding.

Cable extrusion

In the case of cable extrusion (also known as sheath extrusion), the core rope is sheathed. In order for this to work, the so-called extruder melts PVC granulate, presses it and then injects the resulting mass onto the wire ropes. This process is called extrusion or extrusion. After extrusion one no longer speaks of stranded cores but of a cable, because it now has a jacket.

There are two different ways to extrude: pressure extrusion and tube extrusion. Pressure extrusion applies so much pressure that the granulate mass is also injected into the gaps (gussets) of the stranded cores. This is called gusset-filling extrusion. In the case of hose extrusion, these spaces are not filled. The granulate mass just wraps around the core like a hose / jacket.


When braiding, a machine attaches a braid of metallic wires or yarn to the cable. The braid protects the cable from electromagnetic radiation and / or supports the mobility of the cable. This process doesn't just happen with the final cable. The wire ropes can also be spanned with a braid. More about cable protection.

Cable identification

Cable identification helps to reliably identify cables before and after installation and simplifies maintenance. The cables can, for example, be printed or marked with a sign. The cables are then ready for dispatch and ready for use, e.g. in electrical engineering.

Cable in Industry 4.0

In the field of automation technology there has been a rapid development in the last few years, which is not over for a long time in the context of Industry 4.0. In this context, the degree of networking of machines and applications increases and the proportion of data lines increases. The demands on electrical cables and lines are growing, as a failure of the data network would be fatal.


  • artec systems assembles, for example, control lines, sensor lines and ribbon cables, but also individual strands. All products are 'Made in Germany' with focus on a customer-oriented delivery program and innovative solutions.
  • Gutmann Kabel produces copper wires and cables in Germany. The company manufactures cables for all areas and is also known for a wide variety of copper wire products.
  • Lapp Kabel is a provider of cable systems. Despite its global presence, Lapp Kabel has remained a family company and attaches great importance to customer-specific wishes and requirements.
  • MEDI Kabel is a supplier of cables and wires. The Bavarian company has been operating since 1986 and its portfolio includes, among other things, single wires, hoses, fiber optic cables and ribbon cables.
  • In just 70 years, SAB has grown into one of the world market leaders in the field of cables, wires and temperature measurement technology.
  • Scherer Kabel is a cable developer, manufacturer and supplier. The owner-managed family company is characterized by its strong customer orientation.

Other meanings of cable

If you look in the Duden, you can see that a cable does not always have to be an electrical line. When speaking of cable, according to Duden, it can also mean cable television, a telegram or a steel hawser.

Cable television

When one speaks of cable, cable television is often also meant. With this type of television, data (picture and sound) are transported over a broadband cable. Well-known providers in Germany are e.g. Vodafone Kabel Deutschland GmbH and Unitymedia. In addition to television, Vodafone and Unitymedia also offer DSL and telephone connections.

Rope or wire rope

In the nautical language, the word cable is used for a thick rope made of hemp. But it can also be referred to as a wire rope or a steel cable.

Category "Cable: construction, manufacture, application"