Medium voltage cable buyers often ask whether they should specify STA armored cable, SWA armored cable or a non-armored design. The answer depends on installation route, mechanical stress, bending requirement, soil condition, corrosion exposure and project standard. For 26-35kV systems, choosing the wrong armor or sheath can increase installation difficulty and long-term failure risk.
JINCHUAN supplies medium voltage XLPE insulated copper power cables for industrial power distribution, substations, utilities, mines, renewable energy projects and infrastructure networks.
STA vs SWA: What Is the Difference?
| Armor Type | Main Feature | Common Use |
|---|---|---|
| STA | Steel tape armor provides radial mechanical protection | Direct burial or routes with compression risk |
| SWA | Steel wire armor provides stronger tensile support | Vertical routes, pulling stress and demanding installation paths |
| Non-armored | Lighter and easier to handle | Cable trays, ducts or protected indoor routes |
When to Choose Armored Medium Voltage Cable
Armored cable is useful when the cable may face mechanical impact, rodent damage, soil pressure or pulling forces. For buried industrial distribution lines, armor can improve protection. For cable trays inside a controlled facility, a non-armored cable may be sufficient if the route is protected and the project standard allows it.
Important Technical Factors
- Rated voltage: confirm 26/35kV or the exact local voltage designation.
- Conductor: copper conductor size should match current, voltage drop and short-circuit requirements.
- Insulation: XLPE is commonly used for thermal and dielectric stability.
- Screen: metallic screen design affects fault current path and earthing.
- Sheath: PVC, PE, flame-retardant or special sheath options depend on environment.
Standards and Test Documents
Medium voltage extruded power cables are commonly evaluated under IEC 60502-2 for rated voltages from 6kV up to 30kV, while some 35kV project documents may use local or owner-specific standards. Buyers should confirm the applicable standard, routine test report, type test reference, packing list and certificate requirements in the RFQ.
Quotation Checklist
To receive an accurate quotation, provide voltage grade, conductor material, conductor size, core number, insulation, armor type, sheath material, quantity, drum length, destination and required standard. Photos or drawings of the installation route also help the technical team recommend a practical structure.
FAQ
Is STA or SWA better for 35kV cable?
Neither is always better. STA is often chosen for radial protection in direct burial, while SWA is preferred where tensile strength or vertical installation support is important.
Can armored cable be used outdoors?
Yes, if the sheath and structure are selected for moisture, UV exposure, soil condition and mechanical protection requirements.
Why do prices vary for similar 35kV cables?
Price changes with copper size, insulation thickness, armor type, sheath material, testing scope, drum length and raw material market conditions.
Planning a medium voltage project? Send your cable specification to JINCHUAN for structure review, standard matching and quotation support.
