China’s continued rapid economic growth provides a huge market space for cable products, and the wire and cable industry is the second largest industry in China after the automotive industry. The electrical cable is an essential element of any domestic or commercial lighting and power supply, safely transmitting electricity around a building where it’s needed. Various cable types are used in various applications for different purposes and are generally tailored to specific requirements and regulations. This article would like to introduce electrical cables in detail from different perspectives.

What is an electrical cable?

An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current.

One or more electrical cables and their corresponding connectors may be formed into a cable assembly, which is not necessarily suitable for connecting two devices but can be a partial product (e.g., soldered onto a printed circuit board with a connector mounted to the housing). Cable assemblies can also take the form of a cable tree or cable harness to connect many terminals.

What is the use of electrical cables?

Electrical cables connect two or more devices, enabling the transfer of electrical signals or power from one device to another. Long-distance communication takes place over undersea cables. Power cables are used for bulk transmission of alternating and direct current power, especially high-voltage wires. Electrical cables are extensively used in building wiring for lighting, power, and control circuits permanently installed in buildings. Since all the circuit conductors required can be installed in a cable at one time, installation labor is saved compared to certain other wiring methods.

These cables carry electric current to our homes, offices, industries, etc. They are installed in houses, buildings, etc., and they are taken to wherever there is a population and a need for electricity.

What are the components of an electrical cable?

An electrical cable generally consists of an electric conductor, Insulation, auxiliary elements, and outer sheath.

• Electric conductor: which channels the flow of electricity.
• Insulation: it covers and contains the electric flow in the conductor.
• Auxiliary elements: protect the cable and guarantee its longevity.
• Outer sheath: it covers all the mentioned materials protecting them from the outside.

Types of electrical wires conductors

• Bare wire conductor: single wire in a solid state, not flexible, and without coating.
• Aluminum electrical conductors: in some cases, aluminum conductors are also used, even though this metal is a 60% worse conductor than copper.
• Copper electrical conductors: the most commonly used material.
• A flexible copper wire conductor is a set of fine wires covered by an insulating material, and 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.

Thermoplastic Insulation

They are most common in the manufacture of electrical cables are:

PVC: Polyvinyl chloride

Z1: Polyolefins

PE: Linear polyethylene

PU: Polyurethane

Thermosetting Insulation

The most common are:

EPR: Ethylene Propylene

XLPE: Crosslinked Polyethylene

EVA: Ethyl Vinyl Acetate

SI: Silicone

PCP: Neoprene

SBR: Natural Rubber

Tip: Physically, an electrical cable is an assembly consisting of one or more conductors with their insulations and optional screens, individual covering(s), assembly protection, and protective covering(s). Electrical cables may be made more flexible by stranding the wires. In this process, smaller individual electrical wires are twisted or braided together to produce larger wires that are more flexible than solid wires of similar size. Bunching small wires before concentric stranding adds the most flexibility. Copper wires in a cable may be bare or plated with a thin layer of another metal, most often tin but sometimes gold, silver, or some other material. Tin, gold, and silver are much less prone to oxidation than copper, which may lengthen wire life and makes soldering easier. Tinning is also used to provide lubrication between strands, and tinning was used to help remove rubber insulation. Tight lays during stranding makes the cable extensible (CBA – as in telephone handset cords).

Cables can be securely fastened and organized using trunking, cable trays, cable ties, or lacing. Continuous-flex or flexible cables used in moving applications within cable carriers can be secured using strain relief devices or cable ties.

What are the dimensioning criteria of electrical conductors?

There are two sizing criteria for copper conductors:

In the AWG-American Wire Gauge, conductors are defined by specifying the number of wires and the 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 cables that form them. In addition, the actual geometrical sections are smaller than those indicated as nominal.

What are the 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 line’s interior from possible external interference.
• Armors: these are mechanical protections that protect the cable from possible external aggressions: animals, blows, etc.

Types of colors in electrical cables and their meaning

The colors 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 colors, yellow and green. The use of yellow or green single-colored cables is only permitted in places where, for safety reasons, there is no possibility of confusion with the earthing system.

What are the types of electrical cables?

Different types of electrical cables have their specific uses and applications. Today, more than 20 types of cables are designed for applications ranging from the transmission to heavy industry. The following are common cables you may use in your projects: non-metallic sheathed cables, underground feeder cables, metal-sheathed cables, multi-conductor cables, coaxial cables, unshielded twisted pair cables, ribbon cables, direct burial cables, HDMI cables, speaker cables, category 5e cables, twin wire cables, twin spool cables, paired cables, and twisted pair cables.

Non-metallic sheathed cables

These cables are also known as non-metallic building wires or NM cables. They are characterized by a flexible plastic sheath with two to four wires (TECK cables are covered with thermoplastic Insulation) and a bare wire for earthing. This particular variety of cable is intended for underground or outdoor use, in spaces free from moisture and away from any heat sources, and should not be buried or run outside the walls. It is best used behind walls and ceilings and within floor voids. However, NM-B and NM-C non-metallic sheathed cables are the most common form of indoor residential wiring.

Underground feeder cables

These cables are very similar to NM-B cables, but instead of each wire being individually encased in thermoplastic, the wires are grouped and embedded in a flexible material. Similar to NM cables, UF cables are available in various sizes to meet all electrical codes and are marked with the same information as NM cables, plus the UF logo, and are typically used for outdoor lighting and ground applications. Their high water resistance makes them ideal for wet areas such as gardens, open-air luminaires, pumps, etc.

Metal sheathed cables

Also known as armored or BX cables, metal-sheathed cables usually supply main power or large appliances. They have three plain stranded copper wires (a current wire, an earth wire, and a neutral wire) and are insulated with cross-linked polyethylene, a PVC liner, and a black PVC jacket. BX cables with a wire sheath are usually used for outdoor applications and high-stress installations which are relatively expensive and difficult to handle. They are usually found in older houses but not in newly built houses and for indoor use only.

Multi-conductor cables

This cable is commonly used in homes because it is simple to use and well insulated. Multi-conductor or multi-core cables are characterized by having more than one conductor, each of which is individually insulated. In addition, an outer insulation layer is added for added safety. Different varieties are used in the industry, such as the audio multi-core ‘snake’ cables used in the music industry.

Coaxial cables

Coaxial (sometimes helium) cables have tubular Insulation protecting the inner conductor, which in turn is surrounded by a tubular conductive shield and possibly an outer sheath for additional Insulation. Known as ‘coaxial’ because the two inner shields have the same geometric axis, these cables are often used to carry television signals and connect video equipment.

Unshielded twisted pair cables

As its name suggests, this type consists of two wires twisted together. The wires are not insulated, which makes this cable ideal for signal transmission and video applications. As they are more affordable than coaxial or fiber optic cables, UTP cables are often used for telephony, security cameras, and data networks. UTP cables with copper or solid copper cores are popular for indoor use as they are flexible and can be easily bent for in-wall installation.

Ribbon cables

Ribbon cables are commonly used in computers and peripheral devices. Various conductive wires run parallel to each other in a single plane, visually resembling a flat ribbon. These cables are quite flexible and can only handle low voltage applications.

Direct burial cables

Also known as DBCs, these cables are specially designed coaxial or bundled fiber optic cables that do not require additional sheathing, Insulation, or ducting before being buried underground. They feature a heavy metal core with many layers of ribbon metal sheathing, heavy rubber overlays, vibration dampening gel, and a waterproof wrapped thread reinforced tape. High resistance to temperature changes, moisture, and other environmental factors make them popular for transmission or communication requirements.

HDMI cables

It is a rubber cable typically used to transmit digital video, multi-channel surround sound, and advanced control data over a single line. An all-digital audio-video interface that transmits signals in an uncompressed format and is cost-effective. HDMI connector types:

• Type A/B is defined in the HDMI 1.0 specification.
• Type C is defined in the HDMI 1.3 specification.
• Type D/E is defined in the HDMI 1.4 specification.

Speaker cables

They are used to make electrical connections between loudspeakers and audio amplifiers. A zippered type of wire in which two or more electrical conductors are individually insulated in plastic or rubber and can be easily pulled apart.

Category 5e cables

Often referred to as ethernet cable, they meet the industry standard for unshielded twisted pair (UTP) cable and are used to connect telephones, computers, home automation, and A/V networks. Copper cables usually consist of 4 pairs of wires (8 conductors in total) wrapped in a jacket.

Twin wire cables

This is a flat, two-wire cable for transmission between the antenna and the receiver, e.g., for TV and radio.

Twin spool cables

This coaxial cable variant features two inner conductors instead of one and is used for high-speed signals over very short distances.

Paired cables

This cable is typically used for DC or low frequency AC applications with two separate insulated conductors,

Twisted pair cables

This cable is similar to paired lines, but the insulated wires are twisted or interwoven.

Tip: Both non-metallic and metallic sheathed cables require special cutting tools to cut the sheath, but not the internal wires. They also require sleeves inserted at both ends to prevent sharp edges of metal from damaging the cables and special electrical boxes and connectors.

What do labels on the electrical cables mean?

All the information you need to know about a cable type is printed on its sheathing.

• Type: Will list the type of cables, such as NM-B or UF.
• Gauge: The gauge of the individual wires inside the cable, such as 14, 12, 10, etc.
• Number of wires: This Number follows the gauge. For example, 14/2 indicates two 14-gauge wires (a ground wire, if part of the cable, is not included in this number) within the line.
• Grounding: The word “GROUND” or the letter “G” indicates the presence of a ground wire.
• Voltage rating: The most common rating for residential use is 600 volts, but this can vary. The number indicates the maximum voltage the cable can safely carry.
• UL: Indicates that the cable is safety certified and approved for use by Underwriters Laboratories.

Where to buy electrical cables?

A better understanding of cables will ensure your home’s power supply operates efficiently and safely. Need to buy cable or want to learn more about the products?

DelightFire supports standard or custom electrical cables, wire harnesses, and power cords at competitive prices as a professional electrical cable manufacturer. Our manufacturing facility is ISO 14001 certified, UL and ASTA registered, and all products are RoHS and REACH compliant.

Update your electrical products and buy a credible supplier with our latest China production technology. We hope to keep every buyer up to date with this fastest-moving electronic industry and the latest product trends. You can also call or email us and get some buying guides.