1. Look at the packaging. National standard wires are often better made, neat and have a sense of quality when held in hand.

2. Open the package and take a look at the wires inside. The national standard wires of 1.5--6 square meters require a skin thickness (insulation thickness) of 0.7mm. If it is too thick, it is non-standard. Correspondingly The inner core is definitely not enough. You can pull the thread with force. The ones that are not easy to tear are generally the national standard.

3. Burn it with fire. If it goes out within 5 seconds after leaving, there is a certain The flame retardant function is the national standard line.

4. Look at the inner core. The higher the brightness of the inner core material (copper), the better the copper quality. The brightness is uniform, shiny and has no layering. National standards require that the inner core must be made of oxygen-free copper. Non-standard products such as black rod copper may pose accident risks.

5. Countries have certain requirements for the thickness of the inner core, but they are not very strict. But it won't be a lot wrong, just a very small error that can't be seen with the naked eye.

6. For length, the state does not force the rice to be beaten, but many manufacturers also beat the rice. The rice that is beaten does not necessarily meet the national standard, but the general national standard generally does not beat the rice. Non-standard rice is just a means.