How to quickly identify inferior cables? Three tips to distinguish the real from the fake

How to Identify Substandard Cables? Three Tips to Tell if They're Real or Fake
In modern construction and power engineering, cables are the "blood vessels" that carry electrical energy. Their quality is directly related to electrical safety and the safety of life and property. However, some unscrupulous manufacturers still produce and sell inferior cables, passing them off as genuine ones and cutting corners, creating serious fire hazards. According to fire department statistics, approximately 30% of electrical fires are caused by poor quality wires and cables.
So, how can ordinary consumers or project procurement personnel quickly identify inferior cables? No specialized equipment is needed; simply master the following three tips to effectively distinguish genuine cables from counterfeit ones, ensuring safety.
Tip 1: Look—Identify the model and inspect the appearance.
1. Check that the product labeling is complete and clear. Qualified cables will have the manufacturer's name, model specifications, rated voltage, applicable standards, production date, and 3C certification mark clearly printed on their outer sheath. The font should be continuous, clear, and indelible.
Signs of inferior quality include blurred labeling, incomplete information, the absence of the manufacturer's name or address, or even the use of "three no" labels to pass off as genuine products. 2. Observe the outer sheath texture and color.
High-quality cables use new PVC or low-smoke, halogen-free material with a uniform, smooth, and flexible outer sheath. They resist cracking when bent by hand.

Signs of poor quality: The outer sheath is brittle, hard, or too soft, dark in color, has impurities, and cracks with even slight bending. This indicates the cable may be made from recycled plastic.

3. Check the number of cores and wire diameter.

Compare the cable model (e.g., YJV-3×4) to verify the actual number of cores and wire diameter. Use a vernier caliper to measure the conductor diameter and calculate whether the cross-sectional area meets the standard.

Signs of poor quality: A nominal capacity of 4 mm² may be only approximately 3 mm² when measured—this is a typical "shrinkage line," resulting in insufficient current carrying capacity and a high risk of overheating and fire.

Second tip: Weigh—Compare weight to identify potential problems.

Copper is a major component of cable costs. High-quality cables use a sufficient amount of oxygen-free copper and are therefore heavier. To reduce costs, low-quality cables often employ "shortweighting" tactics:
- Reducing the number of copper wires (e.g., 5 strands instead of 7 strands)
- Reducing the conductor diameter
- Adding impurities to reduce purity
Practical Method:
Weigh and compare cables of the same model and length (e.g., 1 meter). For example, 1 meter of BV-4mm² copper wire should weigh around 35 grams. If significantly lighter (e.g., only 28 grams), it is likely a low-quality product.
Tip: Reputable manufacturers have standard weight values ​​for each kilometer of cable. You can ask your supplier for these or refer to national standards for verification.

Third Method: Burning - Flame Retardancy Test to Verify Material

This is the most intuitive identification method (recommended for safe operation).

1. Burning the Insulation to Test Flame Retardancy
Use a lighter to ignite the cable sheath for about 10 seconds, then remove the flame.

✅ High-quality cables (e.g., flame-retardant ZR, low-smoke, halogen-free WDZ): extinguish immediately upon removal from flame, produce minimal smoke, and have no pungent odor.
❌ Low-quality cables: Continuous burning, billowing black smoke, and emitting a pungent plastic odor indicate the use of low-quality recycled materials, which are extremely toxic in the event of a fire.
2. Burning copper wire to test purity
Scrape off the oxide layer on the copper wire and ignite it.
✅ High-quality oxygen-free copper: Burns purple-red, is resistant to breaking, and has good ductility.
❌ Low-quality copper: Brittle and blackened, easily breaks after burning, and may contain impurities such as aluminum and iron.
Additional reminder: Choose reputable channels and request test reports
- Choose reputable brands and reputable dealers when purchasing, and avoid the temptation of low prices.
- Request product certificates, factory inspection reports, and third-party test reports (such as those from the National Wire and Cable Quality Supervision and Inspection Center).
- Verify 3C (China Compulsory Certification) certification. Authenticity can be verified on the official website of the China Quality Certification Center.
Conclusion
Low-quality cables are a ticking time bomb lurking within walls. By mastering the three steps of "look first, weigh second, burn third," even ordinary people can become discerning and effectively avoid risks. Safety is no small matter. Starting with a qualified cable, safeguard electrical safety in homes and projects.
Remember: what you save may be money, but what you lose may be life.