**1, depending on
See whether the quality system certification; see certificate whether the norms; to see whether the name and address, test chapter, date of production; see if printed with trademarks, specifications, and voltage on the wires. Copper core of cross section depends on the wire, Excellence for copper color bright, soft colors, otherwise it is defective.
**2, to try
Preferably the first hand repeatedly bending a wire, all soft, anti-fatigue strength, elastic plastic or rubber handle and no cracks on the wire insulation is the superior product.
3, weighing
Good quality wire, generally within the specified weight range. Such as the commonly used cross-sectional area of 1.5 mm2 plastic insulated single-strand copper wire, each 100 m weight of 1.8 ~ 1.9 kg; 2.5 mm2 plastic insulated single-strand copper wire, each 100 m 3 to 3.1 wt. kg; 4.0 mm2 plastic insulated single-strand copper wire, each 100 m weight of 4.4 ~ 4.6 kg and the like. Poor quality of wire weighs less, or not long enough, or too much copper core wire impurities.
4, see copper
Qualified copper wire copper conductor should be purple, shiny, feel soft. And shoddy copper wire copper core of purple, yellow or white, impurities, poor mechanical strength, poor toughness, that is a little harder to be broken, but often the cables break phenomenon. Check, you just peeled off one end of the wire 2 cm, and then a piece of paper with a little twist on the copper core, if there is a black substance on the white paper, described in Tongxin more impurities. In addition, shoddy wire insulation may seem very thick, in fact, is mostly made of recycled plastic, over time, the insulating layer will be aging and leakage.
5, see price
Due to the low production cost of fake and shoddy wiring, so traders in the sales, often under the guise of cheap low-cost sales, people fooled.