An electrical shock occurs when electric current passes through the body, causing a physiological reaction or injury. Effects range from a slight tingling sensation to severe burns, organ damage, or even death. The body becomes part of an electrical circuit, allowing current to flow through its tissues. Electrical injuries affect thousands annually.
How Electricity Affects the Body
When electricity interacts with the human body, it can disrupt normal biological functions. Electric current typically enters and exits the body, following a path of least resistance through tissues. This current can interfere with the body’s natural electrical signals, which are crucial for nerve impulses and muscle control.
Interference with the nervous system can lead to involuntary muscle contractions, making it difficult to release from the electrical source. If current affects breathing muscles or the heart, it can cause respiratory arrest or cardiac issues like ventricular fibrillation. Beyond electrical disruption, the body’s resistance converts electrical energy into heat. This thermal effect causes internal and external burns, with internal damage often more severe than visible on the skin.
Key Factors in Shock Severity
Injury severity from electrical shock depends on several variables. Current, measured in amperes (A) or milliamperes (mA), is the primary determinant of injury, not voltage. Even low voltages can be dangerous if current is sufficient. For instance, 1 milliampere can cause a faint tingling, while currents above 10-15 mA can lead to muscle paralysis, preventing release from the source.
Voltage provides the “pressure” that drives current through the body’s resistance. Higher voltages overcome skin resistance more easily, allowing more current to flow. The current’s path through the body is also significant; hand-to-hand flow, for example, is particularly dangerous as it may pass through the heart and lungs. Duration of contact with the electrical source directly correlates with harm; longer exposure generally increases injury severity.
Body resistance, influenced by factors like wet skin or calluses, affects current flow. Wet skin dramatically lowers resistance, allowing current to pass more easily and increasing risk. The type of current also matters: alternating current (AC) is more dangerous than direct current (DC) at the same voltage. AC can cause sustained muscle contractions (tetany), making release from the source harder and prolonging exposure.
Everyday Causes of Electrical Shock
Electrical shocks frequently occur in common daily situations. Faulty wiring, damaged insulation, exposed wires, or old and poorly maintained appliances are common culprits in homes. These issues can create direct contact points for electrical current.
Water and electricity form a dangerous combination because water is a good conductor, especially with dissolved minerals. Using electrical devices near water sources, like in bathrooms or kitchens, or handling appliances with wet hands, significantly increases shock risk. Overloaded circuits, which occur when too many devices draw more current than designed, can lead to overheating, damaged wiring, and potential shocks.
Improper use of electrical equipment, such as damaged extension cords or not following safety instructions, also contributes to incidents. Outside the home, accidental contact with power lines, whether downed or touched by objects, can result in severe or fatal shocks. Lightning strikes represent a natural, powerful form of electrical shock, capable of delivering millions of volts and causing extensive damage, including cardiac arrest.