◇ There are three fuses for the knife switch in the market. The fuse says that if there is leakage, the switch will not trip if there is a short circuit, and it will continue to supply power without tripping. The damage caused by continuous leakage, such as personal injury or property damage, is very unsafe. In China, this product was completely eliminated a year ago. What is used in the market in China now is called the leakage protector. Although the leakage protector is safer than the knife switch in the standard of all electricity consumption in China, it will trip automatically if it is too narrow in short circuit. However, this leakage protector still has its shortcomings. For example, when you are supplying power, there is leakage, and when the electricity reaches people, it will trip first, or some electrical appliances have burned out or there is a fire. Also, after this protector trips, you have to push it up by manpower to continuously supply power. This is the shortcoming now, which is very imperfect.