This document specifies the energy efficiency grades, energy efficiency limit values and test methods for arc welding machines, resistance welding machines and handheld laser welding machines. This document applies to arc welding machines and resistance welding machines designed for industrial and professional purposes and supplied at voltages not exceeding those specified in GB/T 156, as well as handheld laser welding machines with a rated output laser power not exceeding 3000W. The resistance welding machine covered by this document specifically refers to the resistance welding transformer permanently installed together with the frame, input circuit and secondary circuit of the rack. This document does not apply to AC TIG arc welders, AC/DC dual-purpose TIG arc welders, frequency level rectifier resistance welders, seam welders, resistance butt welders, flash butt welders, energy storage resistance welders, inverter AC resistance welders, separately sold resistance welding transformers and mechanical equipment driven welding machines.