Understanding Cables: Types, Construction, and Selection Guide
What is a Cable?
A cable is an assembly of two or more electrical conductors, typically insulated and bundled together to transmit power or signals. Cables are vital in:
- Building wiring systems
- Industrial power distribution
- Food processing plant automation
- Control and instrumentation setups
Main Components of a Power Cable
1. Conductor
- Material: Copper or Aluminium
- Type: Solid or stranded (e.g., 7, 19, 37, 61 strands)
- Designation: Shown as 7/A, 19/B, etc., where A, B indicates strand diameter
2. Insulator
Common insulating materials:
- PVC (Polyvinyl Chloride)
- Impregnated Paper
- Butyl Rubber
- Cross-linked Polyethylene (XLPE)
Key Properties of Good Insulation:
- High resistance and dielectric strength
- Low power factor and thermal resistance
- High mechanical strength and heat endurance
3. Inner Sheath
- Protects against moisture
- Common material: Aluminium or Lead alloy
- Used in underground cable installations in food manufacturing zones
4. Armouring
- Reinforced with galvanized steel wire
- Offers mechanical protection during underground or heavy-duty installation
5. Oversheath
- Made from thermoplastic materials
- Shields the cable from dirt, moisture, corrosion, and physical damage
Types of Cable
1. Ribbon Electric Cable
- Multiple insulated wires in parallel
- Used in data transmission, connecting CPUs to motherboards
- Suitable for food automation controls
2. Shielded Cables
- Braided/aluminium foil shielding
- Reduces electromagnetic interference
- Ideal for sensitive instrumentation in food labs
3. Coaxial Cable
- Solid copper/steel conductor with metallic shielding
- Used in high-speed networking, CCTV, audio-visual systems
4.Twisted Pair Cables
- Color-coded twisted copper wires
- Used in telephone lines, networking, sensor signals
5.Fiber Optical Cable
- Transmits data via light
- High bandwidth, EMI-resistant
- Essential for high-speed communication systems in food industry automation
6.Instrumentation Cable
- Flexible, shielded
- Transmits control signals in automated food processing plants
- Withstands electromagnetic interference
7.Underground Cable
- Used in areas unsuitable for overhead wiring
- Multi-core, moisture-resistant
- Common in urban food plant facilities
Selection of Cable
When selecting a cable for food processing factories or engineering facilities, consider:
- System Voltage
- Current Carrying Capacity
- Permissible Voltage Drop
- Short Circuit Rating
Choosing the right cable ensures:
- Electrical safety
- Operational continuity
- Compliance with FSSAI, IEC, and other food industry standards
Conclusion
The proper selection and installation of electrical cables are critical in food industry consulting, process plant design, and engineering services. Whether it’s for control systems, power transmission, or data flow, understanding cable types and specifications helps in building safer, smarter, and more reliable food factories.
References
Frequently asked
What criteria should we use to select cables for a food processing plant?
For cables in food processing factories and engineering facilities, PMG evaluates four core parameters: system voltage, current carrying capacity, permissible voltage drop, and short circuit rating. Selecting on these criteria ensures electrical safety, operational continuity, and compliance with FSSAI, IEC, and other food industry standards, whether the cable serves power transmission, control systems, or data flow.
What are the main components of a power cable and what does each do?
A power cable comprises five main parts. The conductor, in copper or aluminium, solid or stranded (7, 19, 37 or 61 strands, designated 7/A, 19/B and so on). The insulator, in PVC, impregnated paper, butyl rubber or XLPE. The inner sheath of aluminium or lead alloy, which protects against moisture. Armouring of galvanized steel wire for mechanical protection. And a thermoplastic oversheath against dirt, moisture, corrosion and physical damage.
Which cable type suits sensitive instrumentation where electromagnetic interference is a concern?
Shielded cables, using braided or aluminium foil shielding, reduce electromagnetic interference and are ideal for sensitive instrumentation in food laboratories. Instrumentation cable is also flexible and shielded, withstands electromagnetic interference and transmits control signals in automated food processing plants. Fibre optical cable, which transmits data via light, is EMI-resistant with high bandwidth and suits high-speed communication in food industry automation.
What properties define good cable insulation?
Good cable insulation has high resistance and dielectric strength, low power factor and low thermal resistance, plus high mechanical strength and heat endurance. Commonly used insulating materials in power cables are PVC (Polyvinyl Chloride), impregnated paper, butyl rubber, and XLPE (Cross-linked Polyethylene). These properties matter directly to electrical safety and reliable operation in food processing plants.
When do we need armoured or underground cable in a food plant?
Armouring, reinforced with galvanized steel wire, offers mechanical protection during underground or heavy-duty installation. Underground cable is used where overhead wiring is unsuitable; it is multi-core and moisture-resistant, and is common in urban food plant facilities. The inner sheath of aluminium or lead alloy guards against moisture and is used in underground cable installations within food manufacturing zones.
Which cables are used for data and automation signals in a food factory?
Ribbon electric cable carries multiple insulated wires in parallel for data transmission, such as connecting CPUs to motherboards, and suits food automation controls. Twisted pair cables, colour-coded twisted copper, serve telephone lines, networking and sensor signals. Coaxial cable, a solid copper or steel conductor with metallic shielding, is used for high-speed networking, CCTV and audio-visual systems. Fibre optical cable supports high-speed communication systems.
CITE THIS
PMG Engineering. (2022). Understanding Cables: Types, Construction, and Selection Guide. PMG Engineering. https://pmg.engineering/Article/138/understanding-cables-types-construction-and-selection-guide/