What is permissible level of touch ac and dc voltage?

Touch voltage thresholds are related to touch current thresholds by the body’s impedance according to Ohm’s law. Also human body impedance is a function of several factors, such as- the type of power source (DC or AC ); - the magnitude of the touch voltage; - the pathway of the current through the body (hand-to-hand or both hand-to-feet or hand to- seat); - the area of contact with the skin; - the condition of the skin contact area (saltwater-wet, water-wet, dry); - duration of the current flow through human body.