Armored cables are essential in electrical installations that demand extra protection from mechanical damage, moisture, and environmental stress. Whether you're wiring a building, running underground power lines, or protecting circuits in industrial areas, selecting the right type of armored cable is critical for safety, performance, and compliance.
In this guide, we’ll walk through:
What armored cable is
Main types of armored cable
Key differences between them
Where each type is used
Buying tips
🔍 What Is an Armored Cable?
An armored cable is an electrical cable with an added protective layer—typically made of steel or aluminum—to shield conductors from physical damage. The armor layer can be:
Steel Wire Armour (SWA)
Steel Tape Armour (STA)
Aluminum Wire Armour (AWA)
Interlocked armor (typically used in the US)
Armored cables are commonly used in:
Industrial power distribution
Outdoor or underground installations
Harsh or hazardous environments
Direct burial applications
🧱 Main Types of Armored Cable
Here are the most widely used types of armored cables and their features:
1. SWA Cable (Steel Wire Armoured Cable)
Core: Copper or aluminum conductors
Armor: Galvanized steel wire
Sheath: PVC or LSZH
Voltage rating: 600/1000V
Use: Power transmission in fixed installations—often underground or outdoor
🧰 Common in: UK, Europe
📦 Example: 6mm 3 core SWA cable
2. STA Cable (Steel Tape Armored Cable)
Armor: Steel tape (instead of wire)
More flexible, but less resistant to impact compared to SWA
Typically used for indoor installations or ducts
📌 Best for: Low mechanical stress zones
🛡️ Not ideal: Direct burial or high-impact areas
3. AWA Cable (Aluminum Wire Armoured Cable)
Used with single-core cables
Prevents magnetic interference (eddy currents)
Lightweight vs SWA
💡 Typical in: High-voltage single-core systems
⚙️ Standard: IEC 60502-1
4. BX Cable (US Terminology)
Type AC cable (Armored Cable)
Flexible metallic sheath, often used in residential and commercial buildings
Includes bonding strip for grounding
🏠 Used in: Indoor wiring of lighting and power circuits
5. MC Cable (Metal-Clad Cable)
Stronger and safer alternative to BX
Aluminum interlocked armor
Can include multiple conductors and ground
Suitable for wet locations, concealed or exposed
📏 Common standards: UL 1569, NEC Article 330
6. Lead Sheathed Armored Cable
Additional lead layer to resist moisture and chemical corrosion
Often used in underground, oil & gas, or chemical industries
🛢️ Highly resistant to oil, acid, and alkali environments
7. Fire-Resistant Armored Cables
Often include mica tape or mineral insulation
Maintains circuit integrity during fire
Found in emergency systems (e.g., alarms, smoke extractors)
🚨 Standards: IEC 60331, BS 6387
🔄 Comparison Table: SWA vs STA vs MC vs BX
| Feature | SWA | STA | MC (US) | BX (US) |
|---|---|---|---|---|
| Armor Type | Steel wire | Steel tape | Interlocked | Interlocked |
| Rigidity | Rigid | Flexible | Flexible | Semi-flex |
| Indoor/Outdoor | Both | Indoor | Both | Indoor only |
| Direct Burial | Yes | No | Some types | No |
| Grounding Conductor | Separate | Separate | Built-in | Bonding strip |
| Common Voltage Range | 600/1000V | 600V | 600V–5kV | 600V |
🧰 Application Scenarios
SWA Cable: Outdoor lighting, buried power lines, building mains
MC Cable: Commercial buildings, industrial equipment
BX Cable: Home remodels, concealed wall installations
Lead Sheathed Cable: Refineries, chemical plants
Fireproof Armored Cable: Emergency lighting, fire alarms
✅ Tips for Choosing the Right Armored Cable
Check your voltage and current needs
Match armor type to environmental conditions (e.g., corrosion, moisture)
Follow local electrical codes
Consider mechanical protection level needed
Use proper cable glands or termination kits for armored types
📌 Final Thoughts
Understanding the different types of armored cable helps ensure a safe, compliant, and durable electrical system. From SWA to MC, each has its own purpose and application—choosing the right one saves both cost and trouble in the long run.
