Don't get 380 when you pick up 220, and don't get another 220 when you get 380. As for how to connect the lines and ground lines. It's a little bit less current when you get the line, but it doesn't take long. As for common sense, when you weld, you can't see it directly, preferably with a solder cap. The welding must be burnt through, otherwise the welding is not strong, but can not burn the hole.
