More electrical equipment is coming out with safety or hazard-reducing components and welding equipment is no exception. Most welders have had a shock and laughed about it, but it can be serious. The voltage reduction device (VRD) is to welding machines as the safety airbag is to cars.
VRDs reduce the hazard of electric shock by automatically reducing the open circuit voltage (OCV) between the welding output terminals when you are not welding. Welding machines for MMAW and similar CC processes, supply a higher OCV between the electrode and the work when the welding machine is switched on and ready to commence welding. The OCV is often higher (60–100V) than when the arc is established and welding current is drawn (15–35V).
Consequently, the greatest danger occurs when handling the electrodes and the electrode holder between welding operations, such as when changing electrodes.
The VRD will reduce the no-load voltage OCV to less than 35V for DC welding and for AC welding 35V peak or 25V AC rms (‘root mean square’, the effective value of alternating current) when the resistance across the output circuit is 200Ω or greater. It must operate within 0.3 seconds for DC machines with an OCV of over 113V peak.
*The actual severity of each effect will depend on such things as the physical condition of the work area, the physiological condition and resistance of the body, and the area of the body through which the current flows. You must consider every voltage as being dangerous.