It's easy to distinguish between tin-plated and zinc-plated copper busbars. Tin and zinc have different appearances; tin is brighter and whiter than zinc. Tin is a low-melting-point transition metal with a slightly bluish-white luster, while zinc is a light gray transition metal. They are easily distinguishable by comparison.
Tin plating is commonly used on copper busbars. Its functions are twofold: to prevent oxidation and to improve the contact surface of the copper busbar connections. Furthermore, the tin-copper interface forms an alloy, enhancing the adhesion of the plating. Tin also has good electrical conductivity.
Zinc plating is generally not used on copper busbars. Zinc is a reactive metal, typically used for corrosion protection on steel surfaces. Plating zinc on copper busbars would create a galvanic cell effect between the copper and zinc, affecting electrical conductivity and the lifespan of the busbar, thus failing to provide protection.