Many customers who source from Chinese manufacturers fear the worst outcome: samples look like gold, but the bulk order turns out to be scrap metal. This is especially true for SWA cables, which are meant to be buried underground, withstand heavy machinery, and have a lifespan of decades. Even a slight trick in wire thickness or a mere 0.1mm thinner insulation can cause major problems during on-site inspections.
You might have encountered these pitfalls:
- Loose wire strands: Peeling back the sheath reveals loose wires that jump around, easily piercing the insulation with even a slight bend radius. Who would dare bury such cables underground?
- Inferior copper: Claiming to be 99.9% oxygen-free copper, but with excessive resistance, causing overheating after a short period.
- Built-up certificates: Holding a certificate of dubious origin, the entire batch will be returned if inspected on projects in the UK or Middle East.
- Unpredictable delivery times: Orders are said to be placed in 15 days, but after 30 days, the cable is still not finished, leaving construction workers waiting for delivery.
We are a factory dedicated to perfecting SWA cables.
What will you get when you order from us?
- Steel wire that can withstand caliper measurements: Our galvanized steel wire diameter and coverage strictly adhere to standards.
- Genuine LSZH low-smoke halogen-free: It’s fireproof, and it truly is. When burned, it produces only white smoke, no black smoke, and the drippings fully meet standards.
- Fast communication: Send us your technical requirements, and our engineers will provide drawings for confirmation within half an hour, ensuring you can respond to your clients without delay.
- Price: Since you’ve come directly to our factory, we eliminate all middlemen’s markups. For the same quality, we are 10%-15% cheaper than trading companies.
If a buried cable breaks, the cost of digging it up and re-laying it is enough to buy ten times the price of the new cable.
If you currently have a project: Don’t rush to place an order. Send me your specifications first. We’ll provide a quote, which you can compare with your current suppliers.
What is SWA cable?
SWA cable is a power cable consisting of multiple copper (or aluminum) core conductors, an insulation layer, an inner lining layer, a steel wire armor layer, and an outer sheath.
SWA Cable Structure
1. Conductor: Multi-strand stranded copper/aluminum wire.
2. Insulation: Typically made of XLPE (cross-linked polyethylene) or PVC (polyvinyl chloride). XLPE has higher temperature resistance (90°C) and greater current carrying capacity.
3. Bedding: PVC or PE tape, used to protect the insulation from damage by the armor layer.
4. Armor: Constructed of galvanized round or flat steel wire spirally wound, improving tensile strength and lateral pressure resistance.
5. Outer Sheath: Black PVC or black PE (polyethylene). PE has better UV resistance and corrosion resistance, suitable for direct burial; PVC is less expensive and suitable for conduit installation.
SWA cable specifications and parameters
| Cores | Common cross-sectional areas (mm²) | Main uses |
|---|---|---|
| 2 cores | 1.5mm – 400mm+ | Single-phase circuit (live wire, neutral wire) |
| 3 core | 1.5mm – 400mm+ | Single-phase or balanced three-phase with independent ground wire |
| 4 cores | 1.5mm – 400mm+ | Three-phase power supply (L1, L2, L3 + neutral wire) |
| 5 cores | 1.5mm – 95mm+ | Complex industrial control or with independent grounding |
2-core SWA cable specification table
| Conductor cross-sectional area (mm²) | Insulation thickness (mm) | Armored lower diameter (mm) | Armor wire diameter (mm) | Approximate outer diameter (mm) | Approximate weight (kg/km) |
|---|---|---|---|---|---|
| 1.5 | 0.6 | 7.7 | 0.9 | 12.1 | 295-320 |
| 2.5 | 0.7 | 9.0 | 0.9 | 13.6 | 345-365 |
| 4 | 0.7 | 10.1 | 0.9 | 14.7 | 409-440 |
| 6 | 0.7 | 11.3 | 0.9 | 15.9 | 485-470 |
| 10 | 0.7 | 13.2 | 0.9 | 18.0 | 635-810 |
| 16 | 0.7 | 14.7 | 1.25 | 20.4 | 900-978 |
| 25 | 0.9 | 14.7-15.6 | 1.25 | 20.4-24.1 | 938-1240 |
| 35 | 0.9 | 16.7 | 1.6 | 23.3 | 1373-1710 |
| 50 | 1.0 | 19.0 | 1.6 | 25.8 | 1800-1890 |
| 70 | 1.1 | 22.0 | 1.6 | 29.0 | 2320-2450 |
| 95 | 1.1 | 25.1 | 2.0 | 33.1 | 3160-3300 |
| 120 | 1.2 | 27.9 | 2.0 | 36.1 | 3790-4020 |
| 150 | 1.4 | 30.9 | 2.0 | 39.3 | 4500-4750 |
| 185 | 1.6 | 34.9 | 2.5 | 44.7 | 5820-5920 |
| 240 | 1.7 | 39.0 | 2.5 | 49.0 | 7220-7300 |
| 300 | 1.8 | 43.3 | 2.5 | 53.5 | 8710-8770 |
| 400 | 2.0 | 48.4 | 2.5 | 59.0 | 11100-10905 |
3-core SWA cable specification table
| Conductor cross-sectional area (mm²) | Insulation thickness (mm) | Armored lower diameter (mm) | Armor wire diameter (mm) | Approximate outer diameter (mm) | Approximate weight (kg/km) |
|---|---|---|---|---|---|
| 1.5 | 0.6 | 8.2 | 0.9 | 12.6 | 330 |
| 2.5 | 0.7 | 9.5 | 0.9 | 14.1 | 390 |
| 4 | 0.7 | 10.7 | 0.9 | 15.3 | 470-464 |
| 6 | 0.7 | 12.0 | 0.9 | 16.6 | 570-568 |
| 10 | 0.7 | 14.0 | 1.25 | 19.5 | 880-866 |
| 16 | 0.7 | 15.9 | 1.25 | 21.6 | 1070-1152 |
| 25 | 0.9 | 20.1 | 1.6 | 26.7-25.5 | 1550-1800 |
| 35 | 0.9 | 22.6 | 1.6 | 29.4-28.0 | 1940-2230 |
| 50 | 1.0 | 21.7-26.7 | 1.6-2.0 | 28.5-34.7 | 2360-3040 |
| 70 | 1.1 | 25.2 | 1.6 | 32.2 | 3120-3290 |
| 95 | 1.1 | 28.8 | 2.0 | 37.0 | 4310-4440 |
| 120 | 1.2 | 32.0 | 2.0 | 40.4 | 5160-5470 |
| 150 | 1.4 | 35.9 | 2.5 | 45.5 | 6610-6930 |
| 185 | 1.6 | 40.0 | 2.5 | 49.8 | 7920-8350 |
| 240 | 1.7 | 44.9 | 2.5 | 55.1 | 9930-10400 |
| 300 | 1.8 | 49.8 | 2.5 | 60.2 | 11970-12600 |
| 400 | 2.0 | 55.8 | 2.5 | 66.6 | 14770-14600 |
4-core SWA cable specification table
| Conductor cross-sectional area (mm²) | Insulation thickness (mm) | Armored lower diameter (mm) | Armor wire diameter (mm) | Approximate outer diameter (mm) | Approximate weight (kg/km) |
|---|---|---|---|---|---|
| 1.5 | 0.6 | 8.9 | 0.9 | 13.3-13.5 | 380-390 |
| 2.5 | 0.7 | 10.4 | 0.9 | 15.0 | 450-465 |
| 4 | 0.7 | 11.8 | 0.9 | 16.4 | 560-579 |
| 6 | 0.7 | 13.2 | 1.25 | 18.7 | 790-820 |
| 10 | 0.7 | 15.6 | 1.25 | 21.1 | 1040-1090 |
| 16 | 0.7 | 17.7 | 1.25 | 23.4-22.9 | 1300-1400 |
| 25 | 0.9 | 22.3 | 1.6 | 28.9-27.6 | 1880-2160 |
| 35 | 0.9 | 25.1 | 1.6 | 31.9-30.4 | 2350-2690 |
| 50 | 1.0 | 25.0 | 1.6 | 32.0 | 2950-3130 |
| 70 | 1.1 | 29.5 | 2.0 | 37.7 | 4230-4500 |
| 95 | 1.1 | 33.3 | 2.0 | 41.7 | 5390-5600 |
| 120 | 1.2 | 37.5 | 2.5 | 47.1 | 6890-7400 |
| 150 | 1.4 | 41.6 | 2.5 | 51.4 | 8300-8780 |
| 185 | 1.6 | 46.4 | 2.5 | 56.6 | 10070-10630 |
| 240 | 1.7 | 52.6 | 2.5 | 63.0 | 12680-13390 |
| 300 | 1.8 | 58.0 | 2.5 | 68.8 | 15380-16290 |
| 400 | 2.0 | 65.4 | 3.15 | 78.1 | 19950-19800 |
Why Choose SWA Cable? These Four Scenarios Make It Indispensable:
1. Direct Burial (No Pipeline Protection): In urban underground utility tunnels or long-distance power transmission in the field, unarmored cables are susceptible to damage from ground subsidence or heavy road loads, which can instantly break internal optical fibers or conductors. SWA cables withstand compression tests exceeding 5000N/100mm, and their steel wire layer effectively distributes soil pressure—a feature unmatched by ordinary cables.
2. Rodent Control (Rat Protection): In mountainous or suburban substations, rat gnawing on cables is a leading cause of short circuits. SWA’s steel wire layer provides the ultimate physical protection, far more reliable than chemical rodent repellents or thin steel tape.
3. Vertical or Overhead Laying with High Mechanical Tensile Force: In mines or vertical shafts of high-rise buildings, cables are extremely heavy. The steel wire armor layer directly bears the longitudinal tensile force, preventing the copper core from being thinned or even broken due to its own weight.
4. Oil, Gas, and Offshore Platforms: These areas require not only explosion-proof protection but also resistance to seawater corrosion. Galvanized steel wire armor combined with a waterproof and water-resistant strip structure ensures a cable lifespan exceeding 30 years in salt spray environments.
Installation of Steel Wire Armored Cables
Proper installation is crucial to ensuring the performance of SWA cables.
1. Cable Cutting: Use a dedicated armored cable cutting tool to avoid damaging the internal core wires.
2. Stripping the Outer Sheath and Armor: Carefully strip the outer layer, leaving sufficient armor for grounding.
3. Installing the Cable Connector (Gland): Select a matching SWA-specification cable connector, ensuring a seal and grounding.
4. Armor Grounding: The steel wire armor must be reliably grounded to prevent static electricity buildup and the risk of electric shock.
5. Laying Requirements: The bending radius should not be less than 12 times the cable’s outer diameter; avoid excessive bending.
6. Testing: Perform insulation resistance and continuity tests after installation.
FAQ
Q1: Can SWA cables be buried directly underground?
A: Absolutely! The steel wire armor provides ample mechanical protection, making it ideal for direct burial (recommended burial depth ≥ 0.7m, backfill with fine sand).
Q2: How to visually identify genuine SWA cables?
A: ① The outer sheath is clearly marked with “SWA” or “Steel Wire Armored”; ② The armor is tight and not loose when bent; ③ The steel wire surface is evenly galvanized and free of rust.
Q3: What factors affect the price of SWA cables?
A: Copper price fluctuations (conductor material), cross-sectional area, armor density, sheath material (low-smoke halogen-free is more expensive than PVC), brand and certification level.
Q4: Are SWA cables waterproof?
A: SWA cables are inherently moisture-proof, but not completely waterproof. Water can seep in through both ends of the conductor. If submerged in water for extended periods, waterproof connectors (Gland) and heat-shrink sealing caps must be used.
Q5: Does the armor layer of SWA cables need to be grounded?
A: Grounding is mandatory! The steel wire armor layer not only provides mechanical protection but also serves as part of the grounding circuit (CPC). Without grounding, if the insulation fails, the metal sheath may carry high voltage, endangering personal safety.
Q6: What is the difference between SWA and XLPE SWA?
A: They refer to the insulation material. XLPE (cross-linked polyethylene) insulation has a higher temperature resistance (90°C vs. 70°C), about 30% higher current carrying capacity, and is more environmentally friendly than PVC insulation. Modern engineering projects often recommend XLPE insulated SWA.