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How does an electric shock affect the body?

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Quick answer

An electric shock happens when current flows through the body, usually from a live conductor to the ground. The current overrides nerve signals, making muscles contract uncontrollably, and if it crosses the chest it can disturb the heart's rhythm. Larger currents also heat and burn tissue. The danger depends on current, its path and contact time.

An electric shock affects the body when current passes through it, disrupting the electrical signals that control nerves, muscles and the heart while heating tissue along its path. Harm depends mainly on how much current flows, its route through the body, and how long contact lasts.

Step by step

  1. A person touches a live conductor while another part of the body contacts ground or a second conductor.
  2. Voltage drives current through the skin, whose resistance falls sharply when wet, cut or under high voltage.
  3. Current spreads through body tissues, following paths such as hand to hand or hand to foot.
  4. It overrides nerve signals, causing muscle spasms and, across the chest, possible disruption of the heartbeat.
  5. Electrical energy turns into heat along the path, burning skin at contact points and damaging deeper tissue.

Key things to understand

  1. A shock occurs when the body completes a circuit, such as between a live wire and the ground or between two conductors.
  2. Dry skin resists current strongly, but wet or broken skin lets far more current flow at the same voltage.
  3. Current stimulates nerves and muscles, and above roughly 10 to 20 milliamps of mains current, hand muscles may clamp and prevent letting go.
  4. Current crossing the chest can disturb the heart's rhythm, with tens of milliamps enough to trigger ventricular fibrillation.
  5. Higher currents heat tissue along their path, causing burns at entry and exit points and hidden damage to deeper muscles and nerves.

Labelled diagram

  1. Contact point

    Hand touches a live conductor, and current enters through the skin.

  2. Skin resistance

    Dry skin resists current; wet or broken skin lets much more through.

  3. Nerves and muscles

    Current overrides nerve signals, causing spasms and loss of muscle control.

  4. Heart

    Current crossing the chest can disrupt the heart's natural electrical rhythm.

  5. Exit point

    Current leaves through feet or another hand, often leaving a burn.

How current travels through the body during a shock

Real-world examples

  • Touching a faulty metal water heater in a wet Indian bathroom can drive current through the hand and feet to ground.
  • Linemen working on overhead distribution lines wear insulated gloves and use isolation procedures to prevent current flow.
  • A static zap from a car door involves thousands of volts but tiny current, so it stings without injury.
  • Residual current devices cut supply within a fraction of a second, limiting how long a shock can last.

Common mistake

✗ Myth: Only high-voltage power lines can give a dangerous shock; household electricity is too weak to kill.

✓ Fact: Household mains at 230 or 120 volts can drive enough current through the body to stop the heart's normal rhythm, especially through wet skin. Danger depends on current and path, not just voltage.

People also ask

What happens to your body when you get electrocuted?
Current passing through the body overrides nerve signals, causing muscles to contract uncontrollably, sometimes preventing a person from letting go. If it crosses the chest, it can upset the heart's rhythm or stop breathing. It also heats tissue, causing burns at entry and exit points and hidden damage inside, so medical assessment is important.
How much current can kill a person?
For mains alternating current passing across the chest, currents of tens of milliamps lasting around a second can trigger ventricular fibrillation, a chaotic heart rhythm. Around 10 to 20 milliamps can already make it impossible to let go. The exact risk depends on the current's path, duration, frequency and the person's health.
Why is water dangerous with electricity?
Pure water conducts poorly, but everyday water contains dissolved salts that make it conductive. Wet skin also has far lower resistance than dry skin, so the same voltage pushes much more current through the body. Standing in water further improves the path to ground, increasing the chance of a serious shock.
Is it the voltage or the current that hurts you?
Current causes the harm, but voltage determines how much current can be pushed through your body's resistance. That is why a high-voltage static spark with tiny current is harmless, while household mains voltage can drive dangerous currents.
Why can't people let go of a live wire?
Alternating current repeatedly stimulates muscles, causing them to contract continuously. The muscles that close the hand are stronger than those that open it, so a person gripping a live conductor may be unable to release it.
Should someone see a doctor after a minor shock?
A person who has had a mains shock, especially one causing pain, burns, numbness, unconsciousness or palpitations, should see a doctor. Internal damage and heart rhythm problems are not always visible from outside.
Why are birds on power lines not shocked?
A bird sitting on a single wire touches only one conductor, so there is no voltage difference across its body and no current flows through it. A shock happens only when the body bridges two points at different voltages.

Part of the guide: Energy & Electricity at Home →