What's the matter with WEDM's fuse always burning?

This shows that it is more likely to be caused by poor contact. You may still be using the old-fashioned knife switch. If this kind of switch always burns out, the fuse is not too thin, and the switch capacity is generally enough. The surface of the burn is oxidized or uneven, resulting in poor contact. When the contact resistance is high, it will heat up. If it keeps burning, it will not be overloaded or short-circuited, and it will overheat and melt after heating. The fuse is a low melting point alloy. It is best to change the leakage switch or air switch. If not, clean and polish the contact points. In addition, check whether the power cord is locked, whether the screws are loose, and poor contact of the connector will also lead to the same failure.