When a power cord has exposed wires this is treated as a hazard and is unacceptable in the work place. The power cord is protected by RCD/ELCB, fuses and Circuit Breakers to prevent electrocutions from occurring.
Exposed welding wires (electrode and earth clamps) on a welding machine is not protected (norm for over 100 years). The only protection for welders is thick, heavy clothing that become damps, which then lowers the insulation capabilities of the clothing and can cause electrocutions to the welder.
Hierarchy of risk
Stated in the Code Of Practise; Control the risks, there is a 'hierarchy of risk control', which states that the 1st step is to "eliminate the risk" and if this cannot be done in a practical manner then the next step is to "minimise the risk".
According to Ohms Law, fundamental electrical calculation, the reduced voltages (12-30 V) present at the output terminals and the resistance of less than 200 Ohms required by VRD devices to activate full OCV are enough to electrocute the welder. Using these figures in Ohms Law it will become clear what currents can flow through a person and why it is not a certified safety device.
I = V/R = 12 V / 200 Ohms = 60mA (This is 2x to 6x more than RCDs and never fully switch OFF the welding output in 0.3s)
I = V/R = 30 V / 200 Ohms = 150mA (This is 5x to 15x more than RCDs and never fully switch OFF the welding output in 0.3s)
The trip calibration of safety switches (RCD) in hospitals is 10mA while in domestic areas it is 30 mA. They are also designed to switch off in 0.3 seconds and remain off until reset manually. VRDs on the other hand reset automatically and the user is unsure whether the output welding voltage has been safely reduced or not.
In an OH&S article it mentions about electric shocks in welding and says "Currents of approximately six milliamperes (6 mA) can be enough to cause death in some instances". It also mentions that "As a general rule, remind workers to turn the equipment off when not in use".