The term “electrocution” specifically refers to death or severe injury caused by exposure to electrical current. Electrical energy poses an immediate danger to the human body, which is naturally conductive due to its high water and electrolyte content. The potential for lethal injury is always present, even with common household voltages.
How Electricity Kills: Physiological Mechanisms
The primary danger of electrical current is its ability to interfere with the body’s own electrical signals, which govern the heart, lungs, and nervous system. When an external current passes through the chest, it disrupts the heart’s precise electrical impulses. The most frequent lethal mechanism is ventricular fibrillation (VF), where the heart’s lower chambers twitch chaotically, stopping effective blood pumping. This leads to immediate circulatory collapse and oxygen deprivation. Low-voltage alternating current (AC) is particularly effective at inducing VF, sometimes requiring currents as low as 50 to 120 milliamperes (mA) to be fatal.
Current passing through the chest can also lead to respiratory arrest by paralyzing the breathing muscles. Currents greater than 10 mA can cause tetany, or sustained muscle contraction, preventing a person from letting go of the electrical source and prolonging exposure. If the current path involves the brain or spinal cord, it can cause central nervous system damage that results in the cessation of breathing.
Critical Factors Affecting Injury Severity
The severity of an electrical injury is determined not by voltage alone, but by a combination of physical and electrical factors. The true measure of danger is the amount of electrical current, or amperage, that flows through the body.
The path the current takes through the body is another variable, with pathways that cross the chest being the most dangerous. For instance, a current traveling from one hand to the other is highly likely to pass through the heart and lungs, increasing the risk of cardiac arrest. In contrast, a current traveling from a finger to the foot may bypass the most vital organs, though it can still cause severe injury.
The duration of contact is directly proportional to the degree of harm, as longer exposure allows more energy to be delivered to the tissues. The body’s electrical resistance, primarily offered by the skin, also plays a significant role in limiting current flow. Dry skin offers high resistance, but wet or broken skin dramatically lowers this resistance, allowing greater and more damaging currents to enter the body.
Types of Damage Caused by Electrocution
Electrocution causes a range of injuries, even if it does not result in immediate death. Thermal burns are a common consequence, occurring at the points of entry and exit where the current heats the tissue. High-voltage injuries can cause massive internal damage due to the conversion of electrical energy into heat, often much more extensive than external skin burns suggest.
The intense, involuntary muscle contractions caused by the current can lead to severe musculoskeletal damage. These powerful contractions, known as tetany, can result in bone fractures, joint dislocations, and muscle tears. The destruction of muscle tissue releases myoglobin into the bloodstream, a condition known as rhabdomyolysis. This muscle breakdown can overwhelm the kidneys and lead to acute kidney injury or failure.
Neurological deficits are also frequent, including immediate effects like loss of consciousness and seizures. The nervous system can sustain damage that leads to chronic pain, memory disturbances, or peripheral nerve injuries that appear months or years after the initial shock.
Immediate Steps and Emergency Protocol
The safety of the rescuer is the primary priority in any electrical emergency. You must never touch a person who is still in contact with the electrical source, as the current can flow through them and injure you. For high-voltage incidents, such as a downed power line, do not approach the victim until the power company confirms the line is de-energized.
Once the environment is safe, follow these immediate steps:
- Safely interrupt the current by turning off the power source, such as a circuit breaker or main switch.
- If the power cannot be turned off, use a non-conductive object, like a dry wooden stick or plastic pole, to push the person away from the source.
- Immediately call emergency services once the person is separated from the electrical source.
- Check the victim’s responsiveness, breathing, and pulse.
- If the person is not breathing or does not have a pulse, begin cardiopulmonary resuscitation (CPR) immediately if you are trained.
Even if the person appears fine, any significant electrical shock warrants immediate medical evaluation due to the risk of delayed cardiac or systemic complications.