Cable components can vary widely in materials and types, making them complex to understand. Without a clear grasp of parts like conductors, insulation, shielding and connectors, costly mistakes are easy to make when selecting or using cables, leading to performance issues, safety hazards, and expensive rework.
In this post, we’ll break down the key components that make up modern cables. We’ll cover the materials and types for each part, from copper and aluminum conductors to PVC and XLPE insulation to various connector options.

Conductor
The conductor is the core of any cable, responsible for carrying the electrical current or signal from one end to the other. Conductors are typically made of highly conductive metals and can be either solid or stranded in construction.
Materials of Conductors
- Copper: Copper is the most common conductor material due to its excellent electrical conductivity, ductility, and resistance to corrosion. Copper conductors can be bare, tinned, or plated with other metals for enhanced protection and performance.
- Aluminum: Aluminum is another popular conductor material, particularly for high-voltage power transmission cables. While it has lower conductivity compared to copper (about 60% of copper’s conductivity), aluminum is significantly lighter and more cost-effective.
- Other Materials:
- Sliver: Silver has the highest electrical conductivity of all metals and is used in high-end audio cables and some RF connectors.
- Gold: Gold is sometimes used to plate connectors for improved corrosion resistance and signal integrity.
- Nickel-plated copper or copper-clad steel: For high-temperature applications, nickel-plated copper or copper-clad steel conductors may be employed.
Types of Conductors
- Solid: Solid conductors consist of a single, solid wire of the chosen conductor material. Solid conductors are less flexible than stranded conductors but offer lower electrical resistance and are easier to terminate.
- Stranded: Stranded conductors are composed of multiple smaller wires twisted or bundled together. Stranded conductors provide greater flexibility and are less prone to breaking under repeated bending or flexing. However, stranded conductors have slightly higher electrical resistance compared to solid conductors of the same cross-sectional area.
Sizes of Conductors
Conductor size is typically expressed in AWG (American Wire Gauge) or kcmil (thousand circular mils) for larger sizes. The larger the AWG number, the smaller the conductor diameter. Larger conductors have lower resistance and can carry more current, but they also result in a larger and heavier cable.
Insulation
Insulation is the material that surrounds the conductor in a cable. Its primary purpose is to provide electrical isolation between the conductor and other parts of the cable or the surrounding environment.
Materials of Insulation
- PVC (Polyvinyl Chloride): PVC is a widely used insulation material due to its good electrical properties, durability, and low cost. It offers good resistance to moisture, chemicals, and abrasion.
- Polyethylene (PE): PE provides excellent electrical properties, low dielectric loss, and high resistance to moisture and chemicals.
- Cross-Linked Polyethylene (XLPE): XLPE is a modified form of polyethylene that undergoes a cross-linking process to enhance its thermal and mechanical properties. XLPE insulation offers superior heat resistance, allowing cables to operate at higher temperatures compared to standard PE.
- Rubber: Rubber insulation, such as ethylene propylene rubber (EPR) and silicone rubber, provides excellent flexibility, heat resistance, and dielectric strength. They can withstand harsh environmental conditions and are resistant to oils and chemicals.
- Teflon (PTFE): Teflon, also known as polytetrafluoroethylene (PTFE), is a high-performance insulation material. It offers exceptional heat resistance, chemical inertness, and low friction.
Shielding
Shielding protects the signal-carrying conductors from external electromagnetic interference (EMI) and radio frequency interference (RFI). This shielding layer surrounds the insulated conductors and helps to maintain signal integrity, especially in environments with high levels of electromagnetic noise.
Types of Shielding
- Braided Shield: A braided shield consists of a woven mesh of fine metal wires, typically made of copper or aluminum. This type of shielding provides excellent protection against both EMI and RFI, as the interwoven design creates a highly conductive barrier.
- Foil Shield: Foil shielding is made from a thin layer of aluminum or other conductive material that is wrapped around the insulated conductors. Foil shields are often used in combination with a drain wire, which makes contact with the foil and allows for easy grounding.
- Combination Shield: A combination shield, as the name suggests, incorporates both braided and foil shielding to provide the benefits of both types. The foil shield is typically applied first, directly over the insulated conductors, followed by a braided shield.
When Shielding is Necessary
- High-frequency applications: Cables used for transmitting high-frequency signals, such as data cables (USB, HDMI, Ethernet) and coaxial cables, often require shielding to maintain signal integrity. As the frequency of the transmitted signal increases, so does its susceptibility to interference.
- Environments with high levels of electromagnetic noise: In industrial settings, near power lines, or in other environments with high levels of electromagnetic interference.
Jacketing
The outer layer of a cable is known as the jacket or sheath. The jacket protects the inner components of the cable from physical damage, chemical exposure, and environmental factors. It also provides insulation and can enhance the cable’s appearance.
Materials of Jacketing
- PVC (Polyvinyl Chloride): PVC is a widely used jacketing material due to its excellent insulation properties, durability, and resistance to moisture, oils, and chemicals. It is also cost-effective and easy to process.
- PUR (Polyurethane): Polyurethane jackets offer superior mechanical properties compared to PVC. They are highly flexible, abrasion-resistant, and resistant to oils, chemicals, and UV radiation.
- Rubber: Rubber jackets provide excellent flexibility, impact resistance, and resistance to abrasion, oils, and chemicals.
Connectors
Connectors are essential components that allow cables to interface with devices, transmitting signals or power.
Types of Connectors
- HDMI Connectors: Used for high-definition video and audio transmission, commonly found on TVs, gaming consoles, and computers.
- USB Connectors: Universal Serial Bus connectors enable data transfer and power supply between devices. Common types include USB-A, USB-B, USB-C, and mini/micro USB.
- Ethernet Connectors (RJ45): These connectors terminate Ethernet cables, which are widely used for wired networking and internet connectivity. The RJ45 plug locks into the jack for a secure connection.
- Fiber Optic Connectors: Designed for terminating fiber optic cables, these connectors enable high-speed, long-distance data transmission. Popular types include SC, LC, ST, and FC connectors.
- Coaxial Connectors: Used with coaxial cables for RF signal transmission, such as in cable TV, satellite, and antenna connections. F-type is most common in residential settings.
- BNC Connectors: Bayonet Neill-Concelman connectors feature a quick-connect/disconnect design. They’re used in professional video, audio, and RF applications.
- Spade/Ring Terminals: These connectors are crimped or soldered onto the end of wires for secure connections to screw terminals, like those found on some audio equipment and electrical devices.
Supporting Cast
In addition to the main components, cables often incorporate supporting elements that improve performance, protection, and usability:
Filler
Fillers are additional materials placed within the cable to maintain its shape, provide stability, and sometimes aid in waterproofing. They fill the gaps between the conductors and other components. Common filler materials include cotton, jute, polyethylene, or polypropylene yarn.
Armor
In harsh environments, cables may include armor for enhanced physical protection. Armor is typically made of interlocking metal tape or wire braid that wraps around the cable core. It provides defense against abrasion, impact, crushing forces, and in some cases, animal bites or sabotage attempts.
Ripcord
Some multi-conductor cables feature a ripcord – a strong, non-conducting cord placed underneath the cable jacket. The ripcord assists with jacket removal during termination. Pulling the ripcord cuts through the jacket, allowing it to be easily stripped away without damaging the conductors inside.
Wire Color Coding
Color coding is used to identify individual conductors within a multi-wire cable. The specific color scheme depends on the cable type, manufacturer, and applicable standards. Here are some common color coding conventions:
AC Power Cables (US)
- Black, red, or blue indicate live (hot) conductors
- White indicates the neutral conductor
- Green or yellow/green indicates the ground (earth) conductor
DC Power Cables:
- Red indicates the positive (+) conductor
- Black indicates the negative (-) conductor
- Green or yellow/green indicates the ground (earth) conductor
Data Cables (e.g., Ethernet):
- Orange and orange/white are used for transmit signals
- Green and green/white are used for receive signals
- Blue and blue/white are used for additional pairs