Current can flow only if there is a potential difference (voltage) and the amount of current flowing depends on the voltage applied, current sourcing capability, and the resistance between the two points of application. (ohm’s law)
Voltage is the cause and current are the effect. The main cause is the voltage and current as an effect is a killer at a specific rate for a specified period. Current will kill you, but some amount of voltage is required to flow that current in the body breaking the human body resistance. In other words, enough power is required to pass through the human body for proper electric shock.
What is Voltage & Current?
Voltage: the potential difference (a type of force) between two points that causes current to flow in the circuit. It is the force required to move the amount of energy from one point to another.
Current: is the rate of charge flow (electrons) between two points caused by voltage. Voltage is the main cause to push the electrons through a conductor or completed electric circuit.
The human body offers a certain amount of internal resistance. When a voltage is applied to a human body, the amount of current flows through the body depends on the body resistance which varies from person to person.
Though shock is the sensation felt due to the flow of current through the body, voltage is required to cause the flow of current. Ohm’s law states that the Potential difference between 2 points causes the flow of electric current (and not vice versa). Hence, the first cause is a voltage that leads to current flow.
High voltage with a few microamperes causes nothing to the human body like in high voltage supplying cathode ray tube in a traditional TV set or high static voltage in the comb.
An example is the car battery having high amperage with a low voltage level (12V DC) but if we touch both leads, it won’t electrocute. Therefore, enough voltage of a hundredth with enough current makes electric shock to human bodies because the human body like a resistor needs enough power to pass current.
So, electric shock is the combination of both voltage and current.