Anyone with engineering experience knows that buried cables are most vulnerable to two things: soil settlement or heavy pressure deforming the cable, and rodents and termites gnawing through the sheath.
Once a problem occurs with the underground cable, the cost of digging it up and repairing it is far more expensive than the cable itself. If you’re worried about these potential hazards, or if your previous supplier tried to cut corners on steel tape thickness and material, then we need to talk.
We are a direct cable manufacturer from China. We understand that, between cost and quality, overseas customers value “no problems” above all else.
What can we solve for you?
- True double-layer steel tape: Our STA (steel tape armor) uses standard-thickness galvanized steel tape with gaps. Whether it’s heavy machinery crushing or harsh soil pressure, this “armor” must withstand it.
- Rodent and termite protection is standard: Don’t wait until a short circuit occurs to discover the sheath has been gnawed. Our armor layer not only provides physical protection but can also be upgraded to enhance the sheath’s strength as needed, completely preventing biological damage.
- No more middlemen: We connect directly with the factory. Your specifications, deadlines, and pressures are all communicated directly to our technicians. This eliminates the communication costs and time involved with intermediaries.
- No delays: We understand that project milestones are crucial. Our transparent production scheduling system delivers on promised dates without hesitation.
If you currently have a project inquiring about pricing, or are dissatisfied with your existing suppliers, add our contact information.
Don’t rush to place an order; compare our products first. Having an extra reliable factory backup is always beneficial for your project.
What is STA cable?
Steel-tape armored cable is a type of reinforced cable that adds a steel tape armor layer to a regular power cable.
The structure is as follows:
Conductor:
Material: Annealed oxygen-free copper or aluminum.
Class: Class 2 stranded conductor (compliant with IEC 60228 standard). Multi-core cables with a diameter of 35 mm² or more often use sector conductors to reduce the cable’s outer diameter .
Insulation:
Material: XLPE (cross-linked polyethylene). Compared to ordinary PVC, XLPE has a higher temperature resistance rating ( long-term operating temperature 90℃ ) and a short-circuit withstand temperature of up to 250℃ .
Inner lining (Bedding):
The material is usually PVC or LSZH (low smoke halogen-free), which serves as a buffer and isolation between the armor layer and the conductor .
Armor layer:
Multi-core cable: wrapped with galvanized steel tape. This is where the name “STA” comes from.
Single-core cable: The use of steel tape armor is strictly prohibited! For single-core AC cables, non-magnetic materials (such as aluminum tape ATA or aluminum alloy tape) must be used; otherwise, the steel tape will generate eddy currents due to electromagnetic induction, causing the cable to overheat or even burn out .
Outer Sheath:
PVC or PE are commonly used. For direct burial or rodent- and termite-proof environments, HDPE (high-density polyethylene) sheaths are recommended.
Common standard writing style:
Copper conductor: CU/XLPE/STA/PVC (copper core, cross-linked polyethylene insulation, steel tape armor, PVC sheath)
Aluminum conductors: AL/XLPE/STA/PVC
Application Scenarios: Why are STA cables needed?
The function of the STA armor layer is to provide mechanical protection and compressive strength, rather than tensile strength like SWA (steel wire armor).
Typical Application Scenarios:
Direct Burial: No conduit required, direct burial. The steel strip can withstand the pressure from soil settlement and the impact of heavy vehicles passing overhead.
High-Incidence Areas for Rodents/Termites: The steel strip layer acts as a rodent barrier.
Indoor and Outdoor Pipeline Laying: Especially suitable for damp areas, landslide-prone or mobile terrain.
Power Distribution: 0.6/1KV low-voltage distribution and 6KV-35KV medium-voltage transmission and distribution.
STA vs SWA: What are the differences ?
| characteristic | STA (Steel Belt Armor) | SWA (Steel Wire Armor) |
|---|---|---|
| Armor Material | Galvanized steel strip (wrapped) | Galvanized steel wire (concentric stranded) |
| Main resistance | High compressive strength (suitable for direct burial and horizontal laying) | High tensile strength (suitable for vertical laying, tunneling through mountains, and crossing the sea). |
| Bending radius | Smaller (typically 12-15 times the outer diameter) | Larger (usually 15-20 times the outer diameter) |
| cost | Relatively low | Relatively high |
| Applicable Scenarios | Direct burial underground, cable trenches, and ordinary construction sites | Shafts, high drops, underwater, environments requiring tensile strength |
How to select STA cables?
When selecting steel-tape armored cables, the following points need to be considered :
1.Voltage level and cross section : Select 0.6/1kV or higher voltage according to load requirements, and the conductor cross section ranges from 4mm² to 300mm².
2.Number of cores : single core, 3 cores, 4 cores, etc., with multi-core power cables being the most common.
3.Material standards : Prioritize the selection of regular products that comply with GB/T 12706 or IEC standards to ensure the quality of conductors, insulation, and armor.
4.Environmental adaptability : Select the water-resistant type for humid environments and the low-smoke halogen-free type for fire-prone environments.
5.Manufacturers and Certifications : Choose well-known manufacturers with CCC certification and ISO quality system certification to avoid counterfeit and substandard products.
6.Price reference : Based on market conditions, high-quality STA cables are reasonably priced. Do not sacrifice quality for a low price.
Five taboos in STA cable installation
During installation, avoid the following:
- Do not lay the cable if the armor layer is damaged; check the integrity of the steel strip beforehand.
- The bending radius must not be less than 15 times the cable’s outer diameter to prevent cracking of the armor layer.
- When laying the cable directly, lay a 10cm thick layer of fine sand above it, then cover it with a concrete protective slab.
- A dedicated armored grounding terminal must be used at the joint to ensure electrical continuity.
- Avoid laying the cable parallel to heating pipes; maintain a distance of at least 1m between the cable and pipes.
FAQ
Q1: How to choose between STA cables and steel wire armored (SWA) cables?
A: STA cables have excellent resistance to compression and flattening, suitable for direct burial/planar pressure applications; SWA cables have high tensile strength, suitable for vertical suspension and long-span installations (such as mine hoists).
Q2: Does the armor layer need grounding?
A: Single-end grounding is mandatory! This prevents induced current, complies with GB 50168 standards, and avoids safety hazards.
Q3: Can STA cables be used underwater?
A: Ordinary STA cables are not suitable for long-term immersion in water. For underwater projects, steel wire armored cables with a waterproof layer are required.
Q4: Can STA cables be dragged like steel wire ropes?
A: Although STA steel tape is rigid, it cannot withstand large tensile forces. During installation, rough dragging is strictly prohibited; cable netting or a pulling head should be used.
Q5: Can single-core STA cables be used for single-phase equipment?
A: Unless it’s DC power or demagnetization measures such as triangular fixing of single-core cables are taken, AC single-core cables must be armored with non-magnetic armor (aluminum alloy/aluminum/copper).
Q6: Do armored cables need to be installed in conduits?
A: Direct burial does not require conduits. However, if crossing roads or passing through highly corrosive soil, it is still recommended to use corrosion-resistant conduits.
Q7: Can STA cables be used for vertical laying with high drops?
A: Not recommended. Since steel tape cannot withstand vertical tension, steel wire armor (SWA) should be preferred for high-drop or suspended installations.
Q8: What are the common standards for STA cables?
A: They typically conform to international standards such as IEC 60502-1 and BS 5467.