Components of an electrical cable
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Components of an electrical cable
An electric cable consists of:
Electric conductor: which channels the flow of electricity
Insulation: it covers and contains the electric flow in the conductor.
Auxiliary elements: that protect the cable and guarantee its longevity.
Outer sheath: it covers all the mentioned materials protecting them from the outside.
Types of electric conductors
Bare wire conductor: single wire in solid state, not flexible and without coating.
Aluminum electrical conductors: in some cases, aluminum conductors are also used, despite the fact that this metal is 60% worse conductor than copper.
Copper electrical conductors: the most commonly used material.
Flexible copper wire conductor: it is a set of fine wires covered by an insulating material. They are flexible and malleable.
Single-core cable: a cable with a single conductor.
Multi-core cable: a cable that has several conductors.
Types of insulation for electric cables
The insulation consists of placing an insulating coating on the conductor to prevent current leakage. They are classified into two large groups: thermoplastic and thermoset.
1. Thermoplastic insulation
They are most common in the manufacture of electrical cables are:
PVC:Polyvinyl chloride
Z1: Polyolefins
PE: Linear polyethylene
PU: Polyurethane
2. Thermosetting insulation
The most common are:
EPR: Ethylene Propylene
XLPE: Crosslinked Polyethylene
EVA: Ethyl Vinyl Acetate
SI: Silicone
PCP: Neoprene
SBR: Natural Rubber
Types of metal protections for electrical cables
In some cases, the cables may have metal shields.
Screens: these are electrical metal protections applied to isolate the signals that pass through the interior of the cable from possible external interference.
Armours: these are mechanical protections that protect the cable from possible external aggressions: animals, blows, etc.
Nomenclature of electrical cables according to standards
Each cable has a standard designation. This designation is composed of a set of letters and numbers, each with a specific meaning. This designation refers to a series of product characteristics (materials, nominal tensions, etc.) that facilitate the selection of the most suitable cable for your needs, avoiding possible errors in the supply of one cable by another.
When a cable does not clearly indicate these data, it may be a defective cable, which does not comply with safety regulations or guarantee the cable’s life and proper operation.
Designation according to type of insulation
| nomenclature | Cable type |
|---|---|
| R | Crosslinked polyethylene (XLPE) |
| X | Cross-linked polyethylene (XLPE) |
| Z1 | Halogen-free thermoplastic polyolefin |
| Z | Halogen-free thermosetting elastomer |
| V | Polyvinyl chloride (PVC) |
| S | Halogen-free thermosetting silicone compound |
| D | Ethylene-propylene elastomer (EPR) |
Screen designation, interior lining, armature seat
| nomenclature | Cable type |
|---|---|
| C3 | Copper wire screen, helically arranged |
| C4 | Copper shield in the form of a braid, on the assembled insulated conductors. |
| V | Polyvinyl chloride (PVC) |
| Z1 | Halogen-free thermoplastic polyolefin |
If there is no screen, no inner lining and no armature seat, no letter is used.
Designation of the different types of armor
| nomenclature | Cable type |
|---|---|
| F | Steel strapping arranged in a helical pattern. |
| FA | Aluminium strapping arranged in a helical pattern |
| FA3 | Longitudinally corrugated aluminium strip |
| M | Steel wire crown |
| MA | Aluminium wire crown |
Designation of the outer sheath
| nomenclature | Cable type |
|---|---|
| V | Polyvinyl chloride (PVC) |
| Z1 | Halogen-free thermoplastic polyolefin |
| Z | Halogen-free thermosetting elastomer |
| N | Vulcanized chlorinated polymer |
Conductor’s designation
| nomenclature | Cable type |
|---|---|
| K | Flexible copper (class 5) for fixed installations |
| F | Flexible copper (class 5) for mobile services |
| D | Flexible for welding machine cables. When there are no letters on it, the conductor is made of solid copper, class 1 or 2. |
| AL | AL If the conductor is made of aluminium, (AL) is indicated. |
Tensión nominal
| Rated | voltage |
|---|---|
| 0,6/1 kV | Rated voltage 1,000V |
Explanation of the number of conductors
| nomenclature | Cable type |
|---|---|
| nGS | Number and cross-section of wires, in mm2 , with Yellow/Green conductor |
| nxS | Number and cross-section of conductors, in mm2 , without conductor Yellow/Green |
Cable design rules
The cable design rules are also referenced in the marking of each cable:
UNE 21123
IEC 60502
UNE 21150
Additional data
| nomenclature | Cable type |
|---|---|
| CE | CE CE marking is compulsory for the marketing of the product in the European Community. This marking can be on the product or on the packaging. |
| Manufacture date | Date of manufacture (YYMMDD). The date of manufacture is usually placed for traceability purposes. Traceability makes it possible to know who, when and where has carried out each stage of the process and with which materials. |
You can review concepts through this video that we have prepared:
Dimensioning criteria of electrical conductors
There are two sizing criteria for copper conductors:
In the AWG-American Wire Gauge, conductors are defined by specifying a number of wires and a diameter of each wire.
In European sizing (mm2), the conductors are defined by specifying the maximum resistance of the conductor (Ω/km). Solid or flexible conductors are defined by specifying the minimum number of wires or the maximum diameter of the wires that form it. In addition, the actual geometrical sections are somewhat smaller than those indicated as nominal.
Electrical cable measurements
| CROSS-SECTION in mm2 | (AWG) | CURRENT CONSUMPTION | USED |
|---|---|---|---|
| 25 mm2 | 4 | Very high | Central air conditioning and industrial equipment.. |
| 16 mm2 | 6 | High air | Conditioners, electric stoves and electric power connections. |
| 10 mm2 | 8 | Medium high | Refrigerators and dryers. |
| 6 mm2 | 10 | Medium | Microwave and blenders |
| 4 mm2 | 12 | Medium | Lighting |
| 2.5 mm2 | 14 | Under | Lamps |
| 1.5 mm2 | 16 | Very low | Thermostats, bells or security systems. |
Types of colours in electrical cables and their meaning
The colours of the electrical cables are governed by the International Electrical Commission Standard IEC 60446. For the identification of the conductors, the following colors are allowed: black, brown, red, orange, yellow, green, blue, violet, gray, white, pink and turquoise.
Neutral conductor: blue. It is recommended not to use more blue conductors to avoid confusion.
Phase conductor: black, grey or brown.
Protective or earthing conductor: two colours, yellow and green. The use of yellow or green single-coloured cables is only permitted in places where, for safety reasons, there is no possibility of confusion with the earthing system.