Electrocution refers specifically to death caused by the passage of an electrical current through the body. An electric shock is technically any non-fatal physiological reaction resulting from contact with electricity. To understand a fatal event, it is necessary to examine the physical conditions that allow electrical energy to flow through human tissue. Danger occurs when a person accidentally becomes a conductor, allowing sufficient current to pass through the body’s systems.
The Conditions Required for Electric Current to Flow
A person is electrocuted only when they become part of a complete electrical circuit. This circuit requires a path for current to flow from a source, through a conductor, and back to the source or to a ground point. For an injury to occur, the body must establish at least two points of contact: an entry point and an exit point. Breaking this circuit, by disconnecting either the source or the ground connection, immediately stops the current flow.
The severity of the injury is directly related to the amount of electrical current, or amperage, that flows through the body. Voltage, which is the electrical “pressure,” is the force that drives this current through the body’s resistance. While high voltage is often associated with severe injury, it is the amperage that causes the actual tissue damage and physiological disruption.
The body’s natural opposition to current flow is called resistance, with the outer layer of dry skin providing the vast majority of this defense. Internal tissues are highly conductive due to their water and electrolyte content, which is essentially a saline solution. When the skin is wet, its resistance drops dramatically, allowing a much greater and dangerous current to flow at the same voltage.
Alternating current (AC), such as that found in standard household outlets, is considered more hazardous than direct current (DC) at the same amperage. AC frequently induces a sustained, involuntary muscle contraction known as tetany. If this occurs in the hand, the victim may be unable to release their grip from the conductor, prolonging the shock and increasing the likelihood of a fatal outcome.
How Electricity Damages the Body’s Systems
Once sufficient current flows through the body, it causes harm through three primary mechanisms: disruption of bioelectrical signaling, neurological impairment, and thermal injury. The most common cause of death is the disruption of the heart’s natural rhythm. Currents above 50 milliamperes (mA) passing through the chest can trigger ventricular fibrillation (VF). In VF, the heart’s muscle fibers contract rapidly and chaotically, rendering the organ unable to pump blood effectively.
The electrical current interferes with the body’s sensitive nervous system. Nerves communicate using small electrical impulses, and the external current overwhelms these natural signals. This neurological interference can cause the paralysis of the breathing muscles, leading to respiratory arrest, which can occur with currents as low as 30 mA. Current passage may also result in long-term neurological damage, including paralysis or seizures.
Electrical energy is converted into heat as it encounters the body’s resistance, resulting in severe thermal injuries. This causes deep, internal burns along the current’s path, often affecting muscles, blood vessels, and organs beneath the skin. High-voltage contacts generate intense heat, causing extensive damage to internal tissues that may not be immediately apparent from the small entry and exit wounds on the skin.
Common Sources of Electrical Danger
Electrocution incidents often involve scenarios where the electrical circuit is inadvertently completed. Faulty or ungrounded appliances and damaged household wiring are frequent sources of accidental contact with live current. A frayed extension cord with exposed internal wires, for example, can become a direct contact point, especially if used improperly or overloaded.
Water acts as a conductor, creating a hazardous environment when combined with electricity. Electrocution risks are present in swimming pools, hot tubs, and bathtubs due to faulty underwater lighting or defective electrical equipment nearby.
Outdoors, contact with high-voltage power lines presents a hazard, even if direct physical touch is avoided. High voltage electricity can arc, or jump, through the air to a nearby conductor, such as a person or equipment. Downed power lines and improper use of ladders or tools near overhead wires are common situations that lead to fatal incidents.