Introduction
Table of contents
Armoured cable is one of the most versatile and durable electrical cables in the UK. This complete guide to armoured cable explains how it’s built, why it’s widely used, and how to choose the right specification for domestic, commercial, and industrial installations.
What Is Armoured Cable?
Armoured cable — often called SWA cable or steel wire armoured cable — is a power cable reinforced with a galvanised steel wire armour layer.
It’s designed for:
- Underground cable installations
- Outdoor wiring for gardens, garages, and outbuildings
- Industrial environments with vibration, impact, or rodent risk
Browse our full range of Armoured Cables.
Steel Wire Armoured Cable Construction Explained
A typical steel wire armoured cable includes:
- Outer sheath – protects against moisture, oils, and chemicals
- Copper conductor – stranded or solid depending on size
- Copper conductor – stranded or solid depending on size
- Insulation – PVC SWA or LSZH SWA
- Bedding – separates insulated cores from the armour
- Steel wire armour – galvanised wires giving mechanical protection
PVC vs LSZH Armoured Cable
PVC SWA – durable and cost-effective for most outdoor and underground use.
- Popular sizes: 3 Core PVC, 4 Core PVC, 5 Core PVC
LSZH SWA – produces minimal smoke and zero halogen gases in a fire.
- Available in: 2 Core LSZH, 3 Core LSZH, 4 Core LSZH, 5 Core LSZH, 7 Core LSZH
Knowing where each type should be used ensures compliance with UK electrical regulations and safety standards.
Armoured Cable Sizes and Current Ratings
Armoured cables are available in sizes from 1.5 mm² to over 95 mm². The size required depends on the current carrying capacity and the installation method.
- 2 Core SWA – lighting circuits, single-phase power without separate earth
- 3 Core SWA – the most common choice for single-phase with earth
- 4 Core SWA – used for three-phase supplies
- 5 Core SWA – three-phase with neutral connections
- 7 Core SWA – control, signalling, and specialist use
Reference tables in BS 7671 (IET Wiring Regulations) list the exact current ratings.
Best Practices for Underground Armoured Cable Installation
For underground armoured cable installation, follow these steps:
- Bury cable at 450–600 mm depth in domestic settings
- Lay on a bed of sand or fine soil to prevent sheath damage
- Cover with electrical warning tape before backfilling
- Always use proper SWA cable glands for safe termination
These practices prevent accidental damage and ensure compliance with the Wiring Regulations.
FAQs – Guide to Armoured Cable
Is armoured cable waterproof?
Yes, when correctly terminated with glands, the sheath protects against water ingress.
Do I need to use conduit with SWA?
Not usually — the armour is designed to withstand mechanical damage.
Can I use SWA indoors?
Yes, but it’s typically chosen for outdoor or underground runs.
Why Buy SWA Cable from Electrical4Less?
At Electrical4Less, we stock a wide range of armoured cables — from 2 core PVC SWA to 7 core LSZH SWA — all available in multiple sizes. We’re trusted by electricians across the UK because:
- Fast next-day delivery
- In stock ready to ship
- Knowledgeable customer support
- Competitive trade pricing
Whether you’re wiring a small garden project or installing a three-phase supply, we have the cable and accessories you need.
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The Complete Guide to Armoured Cable for UK Installations