How to Test and Tag a Welder


Main points to understand

  • All welders are Class I items
  • Visual inspections are vital to ensure the earth pin has not been modified
  • Must perform Leakage Current testing
  • Models with have either a plastic or metal case
  • ARC welders require an additional test
  • Can range from 15amp to 30amp

Testing and tagging a welder can be a difficult task at times. But with the right know-how, it can be made an easier process.

When testing a welder, it involves checking that there is continuity between the earth pin and the metal casing, as well as the condition of the insulation resistance (due to their control circuits). All require Leakage Current Testing in accordance with AS/NZS 3760.

It's important to remember that there are a couple of models of welder that have a plastic case (rather than the traditional metal case) and therefore there is no exposed metal to connect the reference lead too (the hand piece connections can not be used). In this instance, the earth test can be skipped as it is ‘inaccessible’ (this is an accordance to Australian Standards 3760).

An additional test for ‘ARC Welders’ is to confirm that mains voltage does not appear at the output terminals (where the hand piece and earth clamp connect to the welder). This can be achieved using a standard multimeter.

Remember, we must do a visual inspection before conducting our tests. This involves checking that the earth pin has not been ‘modified’ (generally from a 15 amp ‘large earth pin’ filed down to fit into a 10 amp socket) and that the plug fitted makes the supply current requirements of the unit.

Unfortunately, there is no standard method of indicating this and many manufacturers use a different indication, however here are a couple of common ones:

  • IEFF = 15A: maximum current draw is 15 amps there for a 15 amp plug and supply are required
  • U1 = 15A: maximum current draw is 15 amps there for a 15 amp plug and supply are required
  • Imin = 15A: maximum current draw is 15 amps there for a 15 amp plug and supply are required

Test and Tag a Welder

The above examples are indicating 15 amp requirement, however these can be any number and can be seen as high as 30 amps!

If you are every in doubt as to the correct plug that should be fitted to the welder you are testing just give us a call on 1300 848 302 and we’ll talk you through it.