An electrical shock occurs when a person becomes part of an electrical circuit, allowing current to flow through the body. Household power outlets in the United States typically supply 120 volts of alternating current (AC), which is classified as low voltage. While this voltage is lower than industrial sources, it carries enough potential to cause serious injury or death under the right conditions. The severity of the outcome is highly dependent on factors like the path the current takes and the duration of contact. Understanding the potential for hidden damage is paramount, as even a seemingly minor jolt can have serious unseen consequences.
How Electricity Harms the Body
Damage from an electrical shock is primarily determined by the amount of current, measured in amperes (A), that flows through the body, not the voltage itself. Voltage acts as the force pushing the current, but the body’s electrical resistance dictates how much current actually passes. Dry skin is highly resistant, sometimes offering over 100,000 ohms of resistance, which severely limits current flow. Conversely, wet skin, moisture, or contact with metal can drop resistance dramatically, allowing a much higher, and often fatal, current to flow from a standard 120-volt source.
Electrical current harms the body through thermal destruction and physiological disruption. As electricity moves through tissues, resistance generates heat that causes internal and external burns. Simultaneously, the current interferes with the body’s electrical signaling systems, including the nervous system and the heart. A current of just 6 to 16 milliamperes (mA) can cause a painful shock and loss of muscular control, known as the “let-go” threshold.
The path the current takes through the body is highly significant. A path that crosses the chest, such as from hand-to-hand or hand-to-foot, is exceptionally dangerous because it directly involves the heart and lungs. Current traveling through the chest greatly increases the risk of ventricular fibrillation, an uncoordinated quivering of the heart muscle. Currents exceeding 100 mA, easily achievable with reduced skin resistance from a household outlet, pose a high risk of this life-threatening cardiac event.
Acute Physical Symptoms
The immediate, observable effects of an electrical shock are varied and directly related to the current’s intensity and path. A common initial symptom is muscle tetany, an involuntary and sustained contraction of the muscles. This often causes a person to be unable to release their grip from the live electrical source, prolonging the exposure and escalating the severity of the injury. The intense, painful muscle spasms can be powerful enough to cause secondary mechanical injuries, such as dislocated joints or bone fractures.
Electrical burns occur where the current enters and exits the body. These burns can appear deceptively small on the skin’s surface, sometimes looking like a minor blister or charring. However, the heat generated by the current often causes extensive destruction of tissues, muscle, and bone beneath the skin. Localized pain at the entry and exit sites, along with numbness or tingling, are immediate physical sensations that accompany the shock.
Internal and Delayed Medical Complications
The heart is particularly vulnerable to the disruptive electrical energy, and a major concern is the induction of cardiac arrhythmias. Ventricular fibrillation is the most immediate danger, where the heart’s electrical system is thrown into chaos, preventing it from pumping blood effectively and leading to sudden cardiac arrest. Even if the heart’s rhythm initially appears normal, delayed arrhythmias can develop hours later, necessitating a period of medical observation.
The flow of current through muscle tissue can cause widespread and rapid muscle cell destruction, a condition known as rhabdomyolysis. This breakdown releases large amounts of cellular contents, including the protein myoglobin, into the bloodstream. Myoglobin is toxic to the kidneys, and its presence can quickly lead to acute kidney injury or failure. Aggressive intravenous fluid therapy is often required to flush the myoglobin and protect kidney function.
Neurological complications are also frequent and can manifest immediately or develop over an extended period. Initial symptoms may include headaches, confusion, or seizures, reflecting immediate central nervous system disruption. Peripheral nerve damage, which affects the nerves outside the brain and spinal cord, can cause persistent pain, numbness, tingling, and muscle weakness. Delayed neurological sequelae, such as chronic pain syndromes or progressive paralysis, may not emerge until weeks or months after the initial low-voltage shock.
Immediate Response and Medical Triage
The first step following an electrical shock is to disconnect the power source before approaching the victim. If the power cannot be turned off at the breaker, a non-conductive object, such as a wooden broom handle or plastic item, should be used to separate the person from the source. A rescuer must not touch the person while they are still in contact with the electrical current, as this risks electrocuting the rescuer.
Once the person is safely separated from the power, check immediately for breathing and pulse. If the person is unresponsive and not breathing normally, call emergency medical services and start cardiopulmonary resuscitation (CPR). Any burns should be loosely covered with a sterile gauze bandage or a clean cloth, avoiding materials like blankets that might stick to the wound.
Immediate medical attention is necessary for any person who has suffered an electrical shock, even if they appear fine, due to the high risk of unseen internal damage. Emergency care is required for any loss of consciousness, visible burns, confusion, difficulty breathing, or heart rhythm problems. A medical evaluation is also warranted if the shock involved wet conditions, or if the victim is pregnant or a child. Medical triage involves a thorough examination, often including an electrocardiogram (EKG) to monitor heart activity and blood tests to check for muscle and kidney damage.