what current welding machine should be selected for welding an 8mm thick steel plate?

For welding 8mm thick steel plates (carbon steel), an inverter DC welding machine with a rated output current of 200A is the optimal solution. In actual welding, adjust the current to 180-200A and use 3.2mm welding rods.
Multi-layer welding can ensure penetration. Although a 250A welding machine can be used, it is completely unnecessary in home scenarios, as it only increases costs and the risk of tripping.