In the production of security cables, bare copper wire, tinned copper wire, and copper-clad aluminum (CCA) wire are commonly used for braiding the shielding mesh of coaxial cables and shielded jacketed cables.

Bare Copper Wire
Bare copper wire is drawn directly from pure copper rods. It consists of a single material—copper throughout both its surface and core. Visually, it appears yellow, with shade variations depending on copper purity. Physically, bare copper wire is soft and offers excellent electrical conductivity.

Tinned Copper Wire
The manufacturing process for tinned copper wire is slightly more complex than that for bare copper. Pure copper rods are first drawn into fine wires, then coated with a thin layer of tin through a hot-dip tinning process. This gives the wire a silvery appearance due to tin’s natural color. Tinned copper wire remains relatively soft and maintains good conductivity. Compared to bare copper, it provides significantly better corrosion resistance and oxidation protection, greatly extending the service life of low-voltage cables.

Copper-Clad Aluminum (CCA) Wire
CCA wire is produced using a cladding and welding technique, where a copper strip is concentrically bonded onto the outer surface of an aluminum core rod. This creates a strong metallurgical bond at the atomic level between the copper layer and the aluminum core, forming an inseparable composite material. The wire can be drawn and annealed like a single-metal wire; during drawing, both copper and aluminum reduce in diameter proportionally, keeping the copper volume ratio relatively constant. CCA wire is very lightweight and also appears yellow. However, compared to the other two types, it has significantly poorer conductivity, insufficient flexibility (making it prone to breakage), and lower resistance to corrosion and oxidation. If the CCA production process is not strictly controlled, the finished product may deteriorate rapidly and become useless within a short time.

All three materials—bare copper, tinned copper, and CCA—are widely used for braiding shielding meshes. However, differences in material quality have led to a mixed and often misleading market for low-voltage cables. Notably, CCA wire and bare copper wire share a similar yellow appearance, making them difficult to distinguish at first glance and highly deceptive. This has caused considerable confusion among contractors and engineers regarding which braiding material is superior and how to reliably identify them.

Below are some conventional methods to differentiate among bare copper, tinned copper, and CCA wires, using SYV75-5 video cable braiding as an example:

1. Visual Inspection: Strip off the cable jacket. Tinned copper wire can be immediately identified by its silver color, while the other two appear yellow. Next, cut a section of the cable vertically and neatly, then examine the cross-section of the braid. If it appears yellow throughout, it is bare copper; if it shows a white interior, it is CCA. This distinguishes all three materials.

2. Scratch Test: Scrape the surface of the braided mesh with a tool. For tinned copper, scraping reveals the yellow copper underneath the silver tin layer. Bare copper remains yellow after scratching. In contrast, CCA wire displays white speckles (resembling snowflakes) where the aluminum core is exposed. Rubbing the braid against a concrete floor produces the same effect.

3. Flame Test: Untwist and separate strands of the braided mesh, then hold them near a flame. Copper-based wires (bare or tinned) will melt into spherical beads after burning. CCA wire, however, turns white upon burning, becomes brittle, and crumbles easily when touched.

Additional reliable testing methods include weighing samples on a precision balance, measuring the braid’s resistivity with professional electrical testing equipment, or evaluating oxidation resistance using accelerated aging chambers.

From the above, it is clear that both bare copper and tinned copper are excellent choices for braided shielding. Tinned copper performs even better in terms of oxidation resistance. However, due to the high cost of tin, tinned copper wire is more expensive than bare copper. In contrast, aluminum is very inexpensive, making CCA wire the lowest-cost option—this price advantage has allowed it to dominate the low-end cable market. Unfortunately, because CCA braiding closely resembles bare copper visually, it is frequently used to substitute for genuine copper in fraudulent practices. Given CCA’s poor oxidation resistance and tendency to corrode quickly, such substitutions often lead to repeated project failures and significant financial losses.