Types of Electrical Cables and Where to Use Them: A Practical Guide

By Charles Inyende

 


One of the first things I had to get comfortable with on site was recognizing different cable types at a glance — not just by size, but by construction and intended use. Using the wrong cable type for the application is a common mistake that can lead to premature failure, fire risk, or code violations. Here's a practical rundown of the main cable types and where each one belongs.

1. PVC Insulated Single Core Cable

This is the most basic and widely used cable for general wiring — a single conductor (usually copper) with PVC insulation.

Where it's used: Internal house wiring run through conduit or trunking — lighting circuits, socket circuits, general distribution within walls or ceilings where the cable is protected from physical damage and moisture.

Why it works: PVC insulation is cost-effective, reasonably durable, and adequate for indoor, protected installations.

2. PVC/PVC Twin and Earth Cable

A flat cable containing two insulated conductors (live and neutral) plus a bare or insulated earth conductor, all within an outer PVC sheath.

Where it's used: Common for surface wiring or installations where conduit isn't being used — running cable directly along walls or under floorboards, common in simpler residential wiring setups.

3. Armoured Cable (SWA – Steel Wire Armoured)

This cable has layers of steel wire armoring between the inner insulation and outer sheath, providing mechanical protection.

Where it's used: Underground cable runs, outdoor installations, or anywhere the cable needs protection from physical damage — feeding power to a separate building, workshop, or outdoor structure. The armoring also provides some additional earthing capability.

Why it matters: Without armoring, underground or exposed cables are vulnerable to damage from digging, rodents, or general wear, which can lead to dangerous faults.

4. Flexible Cable (Flex)

Made with multiple fine strands of copper rather than a single solid core, making it bendable and suitable for movement.

Where it's used: Connecting appliances to sockets (the cable on your kettle, iron, or any plug-in appliance), portable equipment, and anywhere the cable needs to flex repeatedly without breaking.

Why it matters: Using rigid cable for an application requiring flexibility leads to cable fatigue and eventual conductor breakage inside the insulation — often invisible until it causes a fault.

5. Coaxial and Data Cables

Not power cables, but worth knowing — used for TV aerial connections, internet, and data transmission. These should always be run separately from power cables to avoid electromagnetic interference.

6. Heat-Resistant Cable

Cable with insulation rated for higher temperatures than standard PVC, which would degrade or melt under heat.

Where it's used: Connections near water heaters, cookers, or any fixed appliance generating significant heat near the wiring connection point.

7. Welding Cable

A highly flexible cable with fine stranded copper, designed to handle high current loads in short bursts typical of welding equipment.

Where it's used: Exclusively for welding machine connections — not a substitute for general power wiring due to its different insulation and construction.

Choosing the Right Cable: Quick Reference

ApplicationRecommended Cable
Internal lighting/socket wiring       PVC single core (in conduit) or twin and earth
Underground/outdoor runsArmoured cable (SWA)
Appliance connectionsFlexible cable (flex)
Water heaters/cookersHeat-resistant cable
Welding equipmentWelding cable

A Mistake I See Often

Using standard flex cable for a fixed, permanent installation (like wiring directly into a wall) instead of proper fixed wiring cable. Flex is designed for flexibility and movement, not for being embedded in a wall or ceiling — over time, this can lead to insulation breakdown that wouldn't happen with the correctly rated cable.

Bottom Line

Choosing the right cable type isn't just about size — it's about matching the cable's construction to where and how it'll be used. Getting this wrong creates hidden risks that often only surface as a fault months or years down the line.

CopperLink Electrical sources and installs the correct cable types for residential and commercial wiring projects across Kakamega County.

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