Arc welders with exposed output terminals: mains and welding leads are inspected for damage or heavy charring; transformer types are tested as Class I equipment with insulation resistance measured from the supply pins to exposed metal and to the output terminals, confirming mains voltage cannot reach the output (informative Appendix J describes welder types; AS 1674.2 adds its own requirements). Portable inverters are now in scope and are tested by the method their product standard (AS/NZS 4763) sets. Totally encapsulated Class I equipment whose earth continuity cannot be reached is checked by careful cord inspection and an insulation test by leakage current or insulation resistance.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.