Electric hazards and their effects on the human body are complex and depend on various factors. The primary danger from electricity is the electric current that passes through the body, which can cause numerous physical responses, including involuntary muscle contractions. For instance, a shock that passes through the trunk of the body with a duration of 1 second and is caused by 60-Hz power can lead to the victim being “thrown” backward due to involuntary muscle contractions that extend the legs and torso.

The physiological effects of electric shock vary depending on the current, irrespective of the voltage. Although voltage is necessary to initiate current flow, the amount of shock-current is influenced by the body’s resistance at the contact points. The severity of an electric shock is primarily determined by the electric current that passes through the body, which is in turn dependent on the voltage and the resistance of the path it follows through the body.

An approximate framework for understanding shock effects includes considering the path of the current through the body, the length of time the body is in the circuit, and other factors such as the voltage of the current, environmental moisture, the phase of the heart cycle when the shock occurs, and the general health of the person prior to the shock.

Electric shock can cause direct injuries like electrical burns, arc burns, and thermal contact burns, as well as secondary injuries due to involuntary muscle reactions. Safety measures are crucial, especially in damp or wet areas where the risk of electrical shock or burns is significantly increased. Higher voltages also increase the risk of death by electric shock.

In essence, electric current can interfere with the functioning of the nervous system and the heart, subject the body to intense heat, and cause muscle contractions. Understanding these effects is vital for implementing effective safety measures in environments where electrical hazards are present.

For more detailed information, you can refer to the following sources:
College Physics, Ohio State University, HyperPhysics, University of Alabama in Huntsville, Cornell University, University of Oregon, Ohioline, and Harvey Mudd College.