1. Check the appearance
When purchasing, pay attention to the appearance, it should be smooth and round with uniform color and nice feel. If it is rubber wire and cable, the sheath and insulation can be burnt with cigarette butts, while the surface is completely undamaged.
2. Check the conductor
The conductor must have a certain sheen as well as moderate flexibility, and the size must meet the standard requirements.The measured values differ greatly, basically the inferior insulated wires (note: there are many bad manufacturers at present, the conductors are not enough cross-section, Increase the thickness of the insulation or sheath to reach the entire outer diameter of the wire to deceive the user).
3. Observe the quality of the conductor
The metal conductor is an important cost of the wire, so some manufacturers will cut corners from this aspect. Good wire with a good copper core, purple-red, bright feel soft. Conversely, if the core purple-black, yellowish, impurities, insufficient strength, easy to break with a fold.
4. The length of the wire and the thickness of the core
Finally, the length of the wire and the thickness of the wire diameter to determine. Good wire length and wire diameter size are in line with national standards. Length literacy difference of no more than 2%, cross-sectional error of no more than 0.02%.