Electrical Cable & Wire Manufacturer

What Is Electrical Cable & How Is It Constructed?

An electrical cable is a group of one or more insulated conductors used to transmit and distribute electrical power. In power systems, cables are used instead of overhead lines when higher safety, aesthetics or environmental protection are required. Typical examples include building feeders, underground distribution, tunnels, industrial plants and renewable energy projects.

A typical power cable is made up of the following elements:

• Conductor

  • Usually annealed copper or aluminium

  • Solid (Class 1) or stranded (Class 2 / Class 5) according to IEC 60228

• Conductor screen (for MV/HV)

  • Semi-conductive layer to smooth the electric field and reduce stress

• Insulation

  • PVC, XLPE or other polymers, selected according to voltage and temperature

• Insulation screen (for MV/HV)

  • Another semi-conductive layer to contain the electric field

• Metallic screen / armour

  • Copper tape, copper wire screen, steel wire armour (SWA) or steel tape armour (STA) for fault-current return and mechanical protection

• Bedding / fillers

  • Non-hygroscopic fillers to keep the cable round and stable

• Outer sheath / jacket

  • PVC or LSZH (low smoke zero halogen) for mechanical protection, UV resistance and chemical resistance

By combining these elements in different ways, we can design electrical cables that safely carry power in harsh industrial environments, underground ducts, outdoor trenches, tunnels or building installations.

Types of Electrical Cable

ZW Cable manufactures a full range of electrical power cables from 0.6/1 kV low voltage up to 220 kV medium- and high-voltage systems. For a more detailed breakdown of common electrical cable types, you can also explore our technical guide.

1. Low Voltage Electrical Cable (LV Cable)

Low voltage (LV) electrical cables are used for final distribution of electricity at rated voltages up to 0.6/1 kV. They form the link between transformers, switchboards, distribution boards and large end-users such as motors, HVAC equipment and building loads. Engineered for industrial and residential power distribution, our LV range features 99.99% oxygen-free copper or electrical-grade aluminium conductors, ensuring reliable conductivity and long service life.

Key features of our LV power distribution cables:

• Insulation: PVC (70°C) or XLPE (90°C) for higher current-carrying capacity.

• Sheath options: UV-resistant PVC, PE, or LSZH (Low Smoke Zero Halogen) for public safety compliance and indoor applications.

• Standards: Fully compliant with IEC 60502-1, BS 7870 and VDE 0276.

For detailed models and constructions, see our dedicated Low Voltage Cable product section.

2. Medium Voltage Cable (MV Cable)

Medium voltage (MV) cables cover the range from 3.6/6 kV up to 26/45 kV or 19/33 kV and are used for distribution networks rather than long-distance transmission. They connect primary and secondary substations, supply large industrial users, and collect power from wind farms and solar plants.

MV electrical power cables are normally single-core or three-core constructions with copper or aluminium conductors, XLPE insulation, inner and outer semi-conductive screens, a copper wire or tape screen and an outer protective sheath. Depending on the installation route, armour and additional water-blocking layers can be added for underground electrical cable routes or high-stress industrial environments.

Typical selection points for MV power cables:

• Conductor material (copper vs aluminium) and cross-section

• Single-core versus three-core construction

• Screen type and short-circuit rating

• Whether mechanical protection (armour) is required for direct burial or industrial areas

For more detail on construction, sizing and installation, you can refer to our guide Medium Voltage Cable Construction, Size and Installation.

3. High Voltage Cable (HV Cable)

High-voltage power cables (66 kV to 220 kV) form part of strategic transmission infrastructure. This is the elite tier of cable manufacturing. Producing cables up to 220 kV requires ultra-clean materials and specialized VCV (Vertical Continuous Vulcanization) lines to prevent insulation sagging during the curing process and to control partial discharge levels.

High-voltage cable construction includes a compacted copper or aluminium conductor, triple-extruded XLPE insulation with inner and outer semi-conductive screens, a metallic screen (usually copper wires and/or tape) and a robust outer sheath. Depending on the project, radial and longitudinal water-blocking elements and armour can be added.

These HV electrical cables are widely used for connections between power plants and substations, between substations, and for bringing high-voltage power into dense urban areas where overhead lines are not suitable.

If you need to dive deeper into design, testing and accessories, please see High Voltage Cable: Everything You Need to Know.

4. Armoured Cable

An armoured cable includes a metal armour layer in addition to the conductor, insulation and sheath. The armour – usually steel wire (SWA) or steel tape (STA) – protects the cable against mechanical impact, soil pressure, moisture and animal bites.

• SWA (Steel Wire Armour): High-tensile wires used on multi-core cables to withstand high pulling tension and external mechanical stress.

• STA (Steel Tape Armour): Metal tape used for crush resistance in direct-burial applications and underground electrical cable routes.

Note: For single-core HV cables, we exclusively utilize AWA (Aluminium Wire Armour) to eliminate magnetic hysteresis losses and reduce heating.

For specific sizes such as  16 mm², 70 mm² or 240 mm², please check our Armoured Cable category for detailed constructions and data sheets.

 Recommended Cable Types

Below is a simplified mapping between common application scenarios and typical cable choices. In real projects, we always confirm the details with your drawings and standards.

How to Choose the Right Electrical Cable?

From an engineering point of view, good electrical cable selection follows a clear logic rather than only “what is in stock”. A simple step-by-step approach is:

1. Confirm system voltage and standard

   • What is the rated voltage of the system (e.g. 0.6/1 kV, 6/10 kV, 8.7/15 kV, 12/20 kV)?

   • Which standard should the cable follow (IEC, BS, VDE, GB or a project specification)?

2. Define the installation method and environment

   • Indoor or outdoor, underground, in ducts, in trays, inside buildings or in tunnels?

   • Any risk of mechanical damage, rodent attack, vehicle loads or impact?

   • Ambient temperature, presence of water, chemicals, oils or sunlight?

   This step determines whether you need armoured cables, special sheathing, LSZH, rubber insulation or flexible constructions.

3. Determine the load and conductor cross-section

   • Rated current and load factor of the circuit

   • Route length and acceptable voltage drop

   • Short-circuit requirements and starting current (for motors)

   Based on these factors, you choose a suitable conductor cross-section and check that the cable can carry the load without overheating. For detailed sizing methods, you can refer to our separate guide on how to choose the optimal electrical cable size or send your load data to us for calculation.

4. Choose between copper and aluminium

   • Copper is preferred for smaller cross-sections, higher current density, compact panels and critical circuits.

   • Aluminium is attractive for longer feeders and larger cross-sections where weight and material cost are important.

   When using aluminium conductors, more attention must be paid to terminations and joints (contact pressure, anti-oxidation compounds, lugs and connectors).

5. Consider fire performance and safety

   • Inside public buildings, tunnels and crowded areas, low smoke zero halogen (LSZH) sheathing may be required.

   • In industrial plants, flame-retardant or fire-resistant cables may be necessary according to local codes or project specifications.

   If you also need to identify conductors quickly during installation and maintenance, refer to our guide on electrical cable colours and colour coding.

6. Define test requirements and documentation

   • Routine tests and sample tests as per standards

   • Type test reports, third-party certificates or factory inspection reports if required

   • Marking, packing and delivery conditions

If you share these key points with us, we can propose a complete electrical cable solution that fits both technical requirements and budget.

Basic Cable Sizing Guide

Exact cable sizing should always follow the applicable design code and detailed calculations. However, it is useful to understand the main factors that affect the cross-section of a conductor:

• Rated current of the load and diversity factor

• Installation conditions – in air, in conduit, in tray, buried in soil, grouped with other cables

• Ambient temperature around the cable

• Permissible voltage drop for the circuit

• Short-circuit withstand requirements for fault conditions

As a very simple illustration for single-phase or three-phase LV circuits with PVC/XLPE insulated copper conductors in typical industrial conditions, the following table gives an idea of how current and cross-section are related:

When you send us the load current, route description and allowable voltage drop, our engineers will select the appropriate cross-section and check it against the relevant code or standard.

Project Experience and Industries We Serve

Over the years, ZW Cable has supplied electrical cables to a wide range of projects, including:

• Commercial and residential buildings

• Industrial plants and factories

• Power generation and renewable energy projects

• Infrastructure such as water treatment, transportation and public facilities

For many projects, we supply complete cable packages, covering LV power, MV power, control, instrumentation and special-purpose cables. We are familiar with working from drawings, BOQs and technical specifications, and we can provide electrical wire cable samples, type test reports or third-party inspections when required by the client or EPC contractor.

Quality Control and Testing

The performance and lifetime of a cable depend heavily on raw materials and process control. In our production, every batch of cables passes through a series of inspections and tests, for example:

• Conductor tests – cross-section, stranding quality and DC resistance

• Insulation and sheath tests – thickness, eccentricity, surface quality

• Spark tests – 100% on-line testing of insulation during extrusion

• Electrical tests – insulation resistance, withstand voltage / AC or DC tests

• Mechanical tests – elongation at break, ageing tests, cold bending as required

• For MV and HV cables – partial discharge and other routine tests according to the relevant standards

All test results are recorded and traceable by production batch. This systematic approach helps ensure that the cable delivered to your site matches the specified design and will operate safely over its expected service life.