Do I need to be qualified to perform resistance welding?

There is no need to get legal qualification.
Resistance welding is the welding method that ensures stable quality by setting the proper welding conditions first. At the time of welding, it is only started by a foot switch, etc., so skill is not required.
However, this facility generates electrode force of several kN to several + of kN and can carry a large current of several thousand A to several tens of thousands A. Therefore, safety training is required for workers.