Electrical cables are essential in nearly every setting, from powering household appliances to driving complex industrial systems. But what exactly makes up an electrical cable?
At its core, an electrical cable is more than just a conductor that carries electricity; it’s a sophisticated assembly of components designed for safety, durability, and optimal performance. Each element of a cable – whether it’s the conductor, wire insulation, shielding, or jacketing – serves a critical purpose and is carefully selected based on the application, environmental demands, and required safety standards.
Understanding the materials and components that make up electrical cables can provide valuable insights into why different cables are chosen for specific uses, and how they are designed to endure varying conditions and hazards. In this post, we’ll break down the essential parts of an electrical cable and explore how different materials contribute to efficient and safe power or data transmission.
What is an electrical cable?
An electrical cable is a bundle of wires or conductors, designed to transmit electrical power or signals from one location to another. These cables are insulated with materials to prevent short circuits and protect users from electric shock.
Electrical cables come in various sizes and configurations to suit different applications, from household wiring to industrial power transmission. They may also include shielding to reduce electromagnetic interference, and some cables are designed to withstand specific conditions, such as high temperature cables and harsh environment cables.
Components of a cable
An electrical cable consists of several key components, each serving a specific function for safe and efficient power or data transmission. Here are the main components:
- Conductors: The core of the cable.
- Wire insulation: A layer of non-conductive material surrounding each conductor.
- Cable shielding: An optional metal layer that surrounds the insulated conductors.
- Cable jacketing: The outermost protective layer.
What are the common cable conductor materials?
The materials used for cable conductors are selected based on their electrical conductivity, durability, and suitability for specific applications. This is often the first step in cable manufacturing, after cable design. Here are the most common materials:
1. Copper
The most widely used material for electrical cable conductors, copper is highly conductive, ductile and durable, making it ideal for both power and communication cables. It is also resistant to corrosion, ensuring a long lifespan for the cables.
2. Aluminium
Lighter and less expensive than copper, aluminium is also commonly used as a conductor – especially in power transmission lines and overhead cables. Although it has lower conductivity than copper, aluminium’s reduced weight makes it easier to handle and install, especially in larger gauges.
3. Silver
Silver has the highest electrical conductivity of all metals, but its high cost limits its use to specialised applications, such as in high-frequency equipment, satellites, and military technology. Silver-plated copper conductors are often used in these settings to reduce costs while improving conductivity.
4. Gold
Although not commonly used for bulk conductors, gold is used in connectors and specialised components due to its excellent conductivity and resistance to oxidation, which helps maintain long-term performance in high-reliability applications.
5. Tinned copper
Copper conductors are sometimes coated with a thin layer of tin to increase corrosion resistance, particularly in wet or humid environments. Tinned copper is commonly used in marine cables and outdoor cables.
6. Nickel-plated copper
For high-temperature applications, nickel-plated copper is used as it withstands higher temperatures and provides good oxidation resistance. It is typically found in heating elements and high-heat industrial applications.
7. Alloys
Some specialised cables use copper or aluminium alloys that offer a balance of mechanical strength and conductivity. These alloys can improve flexibility, corrosion resistance, or other properties specific to the application.
Cable insulation materials
Cable insulation has many benefits, and as such, materials are chosen for their ability to prevent electrical leakage, resist heat, withstand environmental factors, and ensure flexibility and durability. Here are the most commonly used materials:
1. Polyvinyl Chloride (PVC)
PVC is widely used due to its cost-effectiveness, flexibility, and good insulation properties. It is resistant to chemicals, moisture, and abrasion, making it suitable for household wiring, industrial, and outdoor applications. However, PVC has a limited temperature range and can emit toxic fumes when burned.
2. Cross-linked Polyethylene (XLPE)
XLPE is a modified form of polyethylene with cross-linked molecular bonds, which improves heat resistance, making it suitable for high-temperature environments. It has excellent electrical insulation properties, is water-resistant, and is commonly used in high-voltage cables.
3. Ethylene Propylene Rubber (EPR)
EPR is a synthetic rubber with good flexibility, elasticity, and resistance to heat and chemicals. It is often used for high-voltage and medium-voltage cables, as well as in environments with extreme temperatures.
4. Polyurethane (PUR)
Known for its flexibility, abrasion resistance, and resilience, TPU is used in applications that require high durability, such as robotics cables and machinery cables. PUR cables can withstand oils and solvents, making them suitable for harsh industrial settings.
5. Silicone rubber
Silicone insulation is highly flexible and can withstand extreme temperatures, both high and low, as well as UV exposure. It is commonly used in aerospace, automotive, and medical cables where durability in extreme environments is essential.
6. Polyethylene (PE)
PE has excellent dielectric properties and low water absorption, making it suitable for high-frequency and coaxial cables. It is often used in telecommunication cables and outdoor cables, due to its resistance to moisture and chemicals.
7. Fluorinated Ethylene Propylene (FEP) and Polytetrafluoroethylene (PTFE)
These fluoropolymers, including Teflon, are highly heat-resistant, chemically inert, and have low friction. They are used in high-performance cables, such as those for aerospace, medical, and high-frequency applications.
8. Neoprene
Neoprene is a synthetic rubber used primarily in industrial and marine cables due to its resistance to oils, chemicals, and weather. It provides good flexibility and resilience under a range of temperatures and environmental conditions.
9. Rubber (natural and synthetic)
Rubber, both natural and synthetic, provides excellent flexibility, durability, and resilience. It’s used in applications like flexible cables and welding cables, where cables undergo frequent movement and bending.
Cable shielding materials
Cable shielding is used to protect electrical cables from electromagnetic interference (EMI) and radio frequency interference (RFI), and they also prevent signal leakage from the cable. Different shielding materials are chosen based on factors like flexibility, cost, and environmental resistance.
Here are the primary materials used for cable shielding:
1. Aluminium foil
Often used to wrap around individual conductors, or as an overall shield for the entire cable, aluminium foil is lightweight and effective at blocking high-frequency EMI. It’s commonly found in data cables, control cables, and instrumentation cables. To improve flexibility, the foil is often combined with a layer of polyester film.
2. Copper braid
Copper braiding is made of woven copper wires, providing excellent shielding – especially for lower frequencies. It is flexible and durable, making it suitable for applications requiring movement or where cables are exposed to mechanical stress. Copper braid is widely used in audio cables, video cables, and power cables.
3. Aluminium-mylar (foil and braid combination)
This combines an aluminium foil layer with a copper or aluminium braid. This combination provides excellent EMI protection across a wide frequency range and is often used in high-performance data cables, such as Ethernet and coaxial cables.
4. Tinned copper braid
Similar to regular copper braid but coated with a thin layer of tin, this shielding offers better resistance to corrosion, making it suitable for humid or outdoor environments. It is commonly used in marine and industrial applications, where durability is important.
5. Metalised polyester (Mylar) tape
A lightweight, cost-effective shield, metalised polyester (Mylar) tape has a thin layer of metal vapour-deposited onto a plastic film. Although not as effective as foil or braid shields, it provides basic protection and is often used in lower-cost applications like general-purpose data cables.
6. Spiral shield
Made from a single conductor, usually copper, wound around the cable in a spiral pattern, this type of shielding is highly flexible. It is often used in applications requiring frequent flexing, such as audio cables and certain power cables. However, it provides less complete coverage than braided or foil shields.
7. Conductive polymer
Some high-performance cables use conductive polymers as shielding. These materials are lightweight, corrosion-resistant, and flexible, making them suitable for aerospace and automotive applications. Conductive polymers offer an alternative for environments where traditional metal shields may add too much weight or be impractical.
8. Carbon-impregnated tape
In certain specialty applications, such as in cables requiring minimal metallic interference, carbon-impregnated tape can be used as a non-metallic shield. It provides moderate EMI protection and is lightweight and flexible. This is more often found in custom cables.
Cable jacket materials
Cable jacketing, also known as cable sheathing, is the outermost layer of a cable and are crucial for protecting the internal components from physical damage, environmental factors, chemicals, and abrasions. The choice of jacket material depends on the cable’s application, flexibility requirements, and environmental conditions. Here are some commonly used cable jacket materials:
1. Polyvinyl Chloride (PVC)
PVC cable jackets are widely used due to its affordability, durability, and resistance to moisture, chemicals, and abrasion. It can be used in a variety of environments, both indoor and outdoor, but may become brittle in extremely cold temperatures. PVC jackets are commonly found in household wiring, electronics, and general-purpose industrial cables.
2. Polyethylene (PE)
Known for its toughness and water resistance, PE is often used for outdoor cables and underground cables. It has excellent UV and weather resistance, making it ideal for telecommunications and power cables exposed to the elements. PE also has good dielectric properties, making it suitable for high-frequency applications.
3. Polyurethane (PUR)
PUR cables use a rugged material known for its flexibility, abrasion resistance, and resistance to oils and solvents. It is commonly used in environments that require high durability and resilience, such as industrial, automotive, and robotic cables.
4. Chlorinated Polyethylene (CPE)
CPE offers excellent resistance to oils, chemicals, UV radiation, and extreme temperatures. It is highly flexible and suitable for outdoor and industrial applications, including power cables, welding cables, and marine environments.
5. Neoprene
Neoprene is a synthetic rubber known for its flexibility and resilience in harsh conditions. It has good resistance to oil, weather, and heat, making it suitable for marine and industrial applications. Neoprene is commonly used for cables exposed to heavy mechanical stress, such as mining and marine cables.
6. Thermoset Rubber (EPDM)
Ethylene Propylene Diene Monomer (EPDM) rubber is known for its excellent flexibility and durability in extreme temperature conditions, both high and low. It is resistant to UV, ozone, and chemicals, making it suitable for outdoor, industrial, and power transmission applications.
7. Low Smoke Zero Halogen (LSZH)
LSZH cable jackets are made of non-halogenated compounds, which produce minimal smoke and no toxic gases when burned. This makes them ideal for indoor applications where fire safety is crucial, such as in densely populated buildings, hospitals, and airports.
8. Nylon
Nylon is often used as an additional layer over PVC jackets for added abrasion and chemical resistance. It is highly durable and provides a tough, protective outer layer, particularly in industrial settings where cables are subject to wear and tear.
9. Polypropylene (PP)
Lightweight and economical, polypropylene offers good resistance to chemicals, moisture, and temperature. Although less flexible than other materials, it is used in applications where lightweight and rigid properties are required, such as in automotive and appliance wiring.
10. Fluoropolymers (FEP, PTFE, PFA)
Fluorinated materials like FEP (fluorinated ethylene propylene), PTFE (polytetrafluoroethylene), and PFA (perfluoroalkoxy) have excellent thermal stability, chemical resistance, and non-stick properties. These materials are used in extreme environments, such as in aerospace, chemical plants, and high-temperature applications.
How does cable material affect performance and safety?
The materials used in a cable manufacturing has a significant impact on both the cable’s performance and safety. Each material brings unique properties that affect how efficiently the cable can transmit signals or power, withstand environmental stresses, and ensure user safety.
Here’s a closer look at how cable material influences these factors:
1. Electrical conductivity and efficiency
Materials like copper and aluminium are chosen based on their conductivity. Copper has excellent conductivity, meaning lower energy loss and better efficiency, which is ideal for power cables and data transmission. In contrast, aluminium is lighter but less conductive, so it may be used in larger sizes for equivalent performance.
High-conductivity materials help maintain signal strength over long distances, essential for high-frequency applications like telecommunications and data cables. Lower-conductivity materials can lead to signal degradation, impacting data quality and speed.
2. Flexibility and durability
Materials like PVC, PUR, and neoprene provide flexibility, making cables easier to install and use in dynamic environments. Flexible materials help prevent internal wire breakage and extend cable life in applications that involve movement or bending.
What’s more, durable materials resist abrasion, cuts, and impact, protecting internal conductors from exposure and failure. For example, TPU and nylon provide high abrasion resistance in industrial cables, where mechanical stress is common.
3. Temperature resistance and stability
Materials like PTFE and silicone rubber can withstand extreme temperatures, which prevents melting or degradation of the cable in high-heat environments. This stability is essential to avoid insulation breakdown, short circuits, and fire hazards.
However, on the other hand, certain materials, such as polyethylene and EPDM, perform well in cold temperatures, retaining flexibility and preventing brittleness. This prevents cracks that could expose conductors and increase shock risk.
4. Moisture and chemical resistance
Cable materials like polyethylene, neoprene, and CPE provide moisture resistance – essential for outdoor, underground, and marine applications. These materials help prevent water ingress, which could cause short circuits or corrosion of internal conductors, compromising safety and performance.
In industrial settings, cables may be exposed to oils, solvents, or other chemicals. Materials like TPU and CPE resist chemicals, protecting the internal structure from breakdown or corrosion, which maintains the cable’s integrity and safety in harsh environments.
5. Electromagnetic interference (EMI) shielding
Copper braids and aluminium foil are often used for EMI shielding, which is critical in preventing signal interference in data cables. Shielding materials maintain signal quality and prevent cross-talk between cables, particularly important in sensitive electronics and communication applications.
6. Fire safety and toxicity
LSZH materials found in fire resistant cables produce minimal smoke and toxic gases when exposed to fire, reducing health risks and improving visibility during evacuations. This is essential in enclosed or public spaces like hospitals, schools, and transportation hubs, as it enhances fire safety.
Flame-retardant materials, like specific PVC and CPE compounds, slow down the spread of fire along the cable. This can help contain fires in industrial or residential installations, giving people more time to respond and reducing property damage.
7. Environmental impact
Certain cable materials are more environmentally friendly, either through reduced toxic emissions or durability that extends the cable’s lifespan and reduces waste. Some materials, like TPE and specific recyclable polymers, are designed to minimise environmental impact by being more sustainable and easier to dispose of safely.
When it comes to cables, we know a thing or two. To learn more about cable manufacturing and how each different cable works, find more resources and information available on our blog, or contact our helpful team today for expert advice.
