Many buyers only compare prices when purchasing cables, yet pay little attention to raw-material quality. Cables may look identical even if labeled as national-standard products. However, cutting corners on copper or insulation materials creates hidden fire hazards embedded inside buildings. Roughly 70% of a cable's safety performance depends on its raw materials.

1. Copper: the "Heart Conductor" of Cables

Copper serves as the core conductive component. Its purity and quality directly determine current-carrying capacity, heat generation and service life.

Premium high-purity oxygen-free copper

High-purity oxygen-free copper features excellent conductivity and low electrical resistance. It generates minimal heat under continuous full-load operation with controllable temperature rise. It also resists oxidation, avoiding blackening and brittleness over time, so the cable can reach its designed service life. Formal cables for residential and engineering projects adopt high-purity oxygen-free copper.

Common pitfalls of inferior copper

Impure recycled copper

Recycled copper contains impurities such as iron and zinc, leading to high resistivity. Cables with this material tend to overheat under the same cross-sectional area. They struggle to support high-power equipment and suffer accelerated aging during long-term operation.

Copper-clad aluminium / copper-clad iron

Only a thin outer layer is copper, while the inner core is aluminium or iron. Hard to identify with bare eyes, these cables have extremely high resistance. They heat up sharply under heavy current, easily melting insulation layers and creating high risks of short circuits and fire.

Under-sized copper conductor

The actual cross-sectional area falls short of nominal specifications. A cable marked as 4 mm² may only measure 2.5 mm², resulting in far lower actual current-carrying capacity.

2. Insulation & Sheath Materials: the "Safety Protective Suit" for Cables

While copper conducts electricity, insulation materials act as critical safety barriers. They isolate electric current to prevent electric leakage and short circuits, and withstand high temperature, ageing, oil pollution and dampness. Most cable failures stem from insulation breakdown rather than copper fracture.

Qualified insulation materials (PVC / XLPE-Cross-Linked Polyethylene)

• High-temperature resistance: Resists softening and melting under normal operating heat
• Anti-ageing performance: Remains flexible amid long-term electrification and temperature fluctuation, resisting hardening and cracking
• Stable electrical properties: High voltage-withstand capacity against electrical breakdown
• Qualified flame retardancy: Slows flame spread when exposed to fire

PVC is widely used for household BV wires. Cross-linked polyethylene (XLPE), with superior heat resistance, is adopted for high-voltage and fire-resistant cables.

Inferior recycled plastic

Many low-cost cables use waste recycled plastics for insulation and sheaths:

• Poor heat resistance: Insulation softens and melts with slight heating of copper cores, risking short-circuit caused by contact between conductors.
• Prone to ageing and brittleness: Outer jackets harden within just a few years and crack easily upon bending. Buried inside walls out of sight, they bring substantial leakage risks.
• Sub-standard flame retardancy: Burns rapidly with dripping molten material, enabling fire spread along cable runs.
• Insufficient voltage resistance: Vulnerable to electrical breakdown during voltage fluctuations, giving rise to latent faults.

3. Copper and Insulation: Neither Can Be Dispensed With

Two widespread misconceptions prevail:

• "Thicker copper is enough; sheath quality does not matter."
• "A thick outer sheath offsets low-grade copper."

The reality:

• Good copper with poor insulation: Conductivity stays acceptable, yet insulation cracks and ages within years, bringing leakage and fire risks.
• Good insulation with poor-grade copper: Though the sheath looks robust, the conductor generates excessive heat. Sustained high temperature degrades even premium insulation materials.

A qualified cable = high-purity copper conductor + high-quality insulation and sheath, where the two components protect each other.

4. Practical Tips for Buyers

• Check markings: Formal cables are printed with complete model, specification and 3C certification marks.
• Flexibility test: Bend a short segment repeatedly. Quality materials maintain toughness; recycled inferior materials whiten or crack easily.
• Observe copper cross-section: Premium copper shows bright purplish-red colour; inferior copper appears dark and spotted with impurities.
• Reject unreasonably low prices: Raw-material costs set a baseline. Prices far below market average usually mean compromises on copper or insulation.

Closing Remarks

Cables belong to concealed works. Once laid inside walls or cable trays, replacement costs are very high.

Price is superficial; raw-material quality forms the foundation of safety. Cutting expenditure on cables may lead to hidden hazards of electric leakage, short circuits and fire. Choosing cables made of premium raw materials delivers fundamental protection for personal safety and property.