Electricity powers homes and industries, providing countless conveniences. However, it also poses significant hazards when mishandled. Understanding how electrical current affects the human body is important for preventing injuries and ensuring safety.
Understanding Electrical Flow
Electrical interactions involve three fundamental properties. Voltage measures electrical pressure, which drives the charge. Current, measured in amperes (amps), represents the flow of electrical charge through a circuit. Resistance, measured in ohms, describes how much a material opposes this flow. These three elements are interconnected: higher voltage forces more current through a given resistance, and higher resistance limits current flow for a given voltage.
The Lethal Current: Beyond Amps
The danger of an electric shock extends beyond just the number of amperes. Several factors determine the severity of an electrical injury. Voltage plays a role, as higher voltage forces more current through the body’s natural resistance. Body resistance varies significantly; dry skin offers hundreds of thousands of ohms, while wet skin or internal tissues present only a few hundred ohms. This means a much lower voltage can become dangerous when skin is wet.
The current’s path through the body also determines injury. Current flowing across the chest, involving the heart, or through the head, affecting the brain and respiratory control, is more hazardous than current passing solely through a limb. A common dangerous path is from one hand to a foot, placing the heart directly in the current’s path. The duration of contact also impacts harm; longer exposure allows more electrical energy absorption, leading to greater tissue damage.
The type of current, alternating current (AC) or direct current (DC), influences physiological effects. AC, common in household circuits, is often more dangerous than DC at the same voltage because it can induce sustained muscle contractions, preventing release. AC is also more likely to cause ventricular fibrillation, a life-threatening irregular heartbeat. Different current levels produce distinct effects: 1 milliampere (mA) might be barely perceptible, while 10-20 mA can cause involuntary muscle contractions that make release difficult. Currents between 100-200 mA passing through the heart are often associated with fatal ventricular fibrillation.
How Electricity Harms the Body
When electricity courses through the human body, it disrupts normal physiological functions. One immediate effect involves the heart. Electrical current can interfere with the heart’s natural electrical rhythm, potentially inducing ventricular fibrillation, a chaotic quivering of the heart muscle. This prevents the heart from pumping blood effectively, leading to rapid cardiac arrest.
The respiratory system is also vulnerable. Electrical shock can cause paralysis of breathing muscles, such as the diaphragm and intercostal muscles, leading to respiratory arrest. Damage to the central nervous system, including the brain, can result in seizures, loss of consciousness, and neurological impairments.
Another injury from electrical current is burns. As electricity travels through the body, it encounters resistance, converting electrical energy into heat. This heat causes internal tissue damage, often more extensive than visible on the skin’s surface, affecting muscles, bones, and internal organs. External burns typically appear where current enters and exits the body. Strong, involuntary muscle contractions can also cause bone fractures, joint dislocations, and other musculoskeletal injuries, or lead to secondary injuries from falls.
Safety Measures and Emergency Response
Safety Measures
Preventing electrical injuries relies on understanding and respecting electricity’s dangers. Key safety measures include:
- Regularly inspect electrical cords for damage, such as fraying or exposed wires, and replace them immediately.
- Avoid overloading electrical outlets with too many devices to prevent fire hazards and shock risks.
- Keep electrical appliances and cords away from water and damp environments, as water significantly reduces the body’s resistance.
- Install Ground Fault Circuit Interrupters (GFCIs) in moisture-prone areas like bathrooms, kitchens, and outdoors. GFCIs quickly shut off power upon detecting a dangerous current imbalance.
- Ensure all electrical systems and appliances are properly grounded.
- Educate children about electrical safety from a young age.
Emergency Response
In an electrical shock event, immediate action can be life-saving. Never touch a person still in contact with an electrical source, as this can shock the rescuer. Instead, cut off the power supply immediately by flipping a circuit breaker or unplugging the appliance if safe. If power cannot be turned off, use a non-conductive object, like a dry wooden stick or plastic broom handle, to separate the person from the source, only if absolutely necessary and safe.
Once the person is no longer in contact and the area is safe, call emergency services. Check for breathing and a pulse; if absent, administer CPR if trained. Cover any burns with a sterile dressing and keep the person warm. Remain with the individual until professional medical help arrives for reassurance and monitoring.