1️⃣⭕ First look at the quality system certification; See whether the certificate is standard; See whether there is a factory name, factory address, inspection seal, production date; See if the wire is printed with trademarks, specifications, voltage, etc. But also look at the cross section of the wire copper core, excellent copper color bright, soft color, copper core yellow red, indicating that the quality of the copper used is better, and yellow white is a reflection of low quality copper.
2️⃣⭕ It is advisable to bend a wire head repeatedly by hand, and those with soft feel, good fatigue strength, large plastic or rubber feel elasticity and no crack on the wire insulator are excellent products. Wire outer plastic skin should be bright color, fine texture, lit with a lighter should be no open flame.
3️⃣⭕ Cut off a section of insulation layer to see if its wire core is located in the middle of the insulation layer. Not in the middle is due to the process is not high and caused by the core phenomenon, in the use of small power can still be safe, once the power consumption is large, the thinner side is likely to be current breakdown.
4️⃣⭕ Be sure to see whether the length and thickness of the wire core have been manipulated. In the relevant standards, the error of the length of the wire can not exceed 5%, the diameter of the section can not exceed 0.02%, but there are a lot of short weight in the length of the market, in the section of fraud (such as indicating the section of 2.5 square millimeters of the line, in fact, only 2 square millimeters thick) phenomenon.