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Cable vocabulary

Cable manufacturing:

Laying up: A work stage in which the different elements of the cable are combined; can be completed in a single step or several steps.

Cross-linking: A process in which chemical bonds are formed between molecules in a polymer. The process is often referred to as “curing” plastic.

CV line: CV is an abbreviation of the words “continuous vulcanisation”. The CV line is used for isolating the conductor and forming cross-links in the plastic insulation for improved properties. In practice, this means curing polyethylene at high pressure and temperature.

Drawing: A cold forming process in which raw material (aluminium or copper) is drawn through a hole in a die made of hard material. There may be several dies along the drawing line, and the hole diameter of the last die determines the final diameter of the wire.

Extrusion: A work stage in which plastic raw material is melted and extruded at high pressure and temperature, forcing it into the cable’s structure. Extrusion is most commonly used for wire insulation and to form the outer sheath of the cable.

Cable structure:

Armoured cable: A cable protected by a layer of metal wires or tapes under the sheath. Depending on the cable structure, the most typical armouring materials include galvanised steel, aluminium and copper.

Bedding: A structural layer inside the cable protecting the layer below. Semiconducting taping, for example, is used as bedding below the metallic screen, forming a base for copper wires.

Conducting material: Any material allowing electricity to pass through it. In addition to the actual conductors, conducting materials are utilised in many other layers of the cable.

Conductor: The innermost part of the cable responsible for carrying the electrical current.

Electrolytic copper: An extremely pure form of copper which has been purified electrolytically to provide the optimal electrical conductivity.

Insulating material: Any material preventing electrical current from passing through it. In addition to the actual insulation, insulating materials are utilised in other layers of the cable.

Twisted pair: Two insulated wires twisted together. The twisted pair is a basic element in almost all data transfer and signal cables.

Metallic screen: A layer between the insulation and sheath typically made of aluminium or copper, providing a path for earth fault and charging currents. At least one end of the metallic screen must be earthed.

Sheath: The outer layer of the cable, providing support for the structures below and protecting them against moisture and mechanical stress. The most typical sheath materials include PE and PCV plastics

General information about cables:

Fire performance: Describes how the cable handles in case of fire. Several different standards set requirements for the performance of cables in various circumstances.

Fire rating: Specifies the time and fire test conditions in which the cable remains functional. The most typical applications for fire-rated cables include hospitals and other public spaces.

Flame retardant: The cable’s flame propagation rating indicates the rate at which the cable will spread fire once it has caught fire. Flame retardant cables are typically used in hospitals and other public spaces.

HV: High Voltage. A cable or system with a voltage higher than 52 kV.

MV: Medium Voltage. A cable or system with a voltage in the range of 6–42 kV

LV: Low voltage. A cable or system with a voltage no higher than a few kilovolts.

Power cable: A cable specifically designed for carrying electrical power.

Specialty cable: A cable designed for a special purpose. Can be a power cable, signal cable or a combination of both.

Materials:

Plastic compound: A homogenous mixture of polymers, fillers and additives. Fillers and additives are used in order to achieve the required properties.

Filler: A material or layer included in the cable structure to provide the required features or properties, such as water-tightness or specific fire properties.

Halogen free: A polymer or other material which includes no base elements of the halogen group. The most common halogen-free polymer is PE, polyethylene.

Halogenated polymer: A polymer which includes base elements of the halogen group, most typically chlorine. Halogenated polymers emit poisonous gases and a lot of smoke during combustion. The most common halogenated polymer is PVC, polyvinyl chloride.

FRHF: An abbreviation of “Fire Retardant Halogen Free”, used for cables which do not propagate fire and remain functional in case of fire, even if installed as bundles.

Polymer: A long-chain hydrocarbon generated by combining several short hydrocarbon molecules into long chains.

Polyethylene: A polymer produced from ethylene monomers, a common material in sheaths and insulations. Extremely flammable.

PVC: Polyvinylchloride. A halogenated polymer (with chlorine) which does not catch fire easily, but emits poisonous gases and a lot of smoke during combustion. Used both as insulation and in sheaths.

Semiconducting layer: A polyethylene-based compound with added carbon promoting electrical conductivity. Used in medium- and high-voltage cable insulation to even out variations in the local electrical field.

XLPE (PEX): An abbreviation of “Cross-linked Polyethylene”. Electrically, mechanically and chemically more durable than standard polyethylene. XLPE includes additional cross-links between polymer chains. Used in cables as insulation.

Miscellaneous:

Cable accessory: Any accessory used for cable installation, such as fastening, terminating or extending the cable.

Coil: Small cable quantities are delivered as coils. Coils are typically plastic-wrapped or packaged in small boxes.

Reel: Larger quantities of cable are usually delivered spooled on large wooden or plastic reels or drums. Reel widths range from tens of centimetres to more than three meters.

Joint: A product which allows a cable to be extended by connecting it to another without compromising the safety or performance of the system.

Cable termination: A device used especially in middle- and high-voltage cables, allowing the cable to be connected to, for example, air insulated systems. Cable terminations are used for sealing the cable end and to redirect the cable's electrical field to prevent faults.

Standard: An internationally-accepted set of rules establishing the proper conduct and way of manufacturing specific products. For example, cable manufacturing is governed by national, European and international standards.