Electric shock¶

Electrical injuries are deceptive and complex emergencies. While the visible skin contact points may appear as minor, harmless surface burns, electrical current passing through the human body generates intense internal thermal energy that cooks deep muscle compartments, damages blood vessels, disrupts cardiac conduction, and shatters bones. The primary rule of electrical rescue is rescuer safety: entering an electrified zone without proper power isolation creates a secondary casualty.

This guide provides clinically validated emergency procedures based on directives from the Occupational Safety and Health Administration (OSHA), the American Heart Association (AHA), the International Liaison Committee on Resuscitation (ILCOR), and burn surgery consensus guidelines to break electrical contact, prevent ventricular fibrillation, evaluate step potential hazards, and manage internal injuries.

Do this now¶

If an individual experiences an electric shock:

1. Do not touch the person with your bare hands, clothing, or conductive materials while they are still in contact with the electrical source. Electricity passes effortlessly from the victim into your body.
2. Call your local emergency number immediately (911 in the United States and Canada, 112 in the European Union, 999 in the United Kingdom).
3. Cut the power source immediately at the primary circuit breaker, fuse box, emergency disconnect lever, or wall outlet switch. If an appliance cord is safe to grasp, unplug it by pulling the insulated plug casing, not the damaged cord.
4. If power cannot be immediately deactivated and the current is low voltage (household 120 to 240 volts AC), separate the victim from the source using a dry, non-conductive tool made of wood, fiberglass, or thick plastic. Stand on a dry, non-conductive surface such as a wooden board, rubber mat, or stack of newspapers.
5. Once electrical contact is broken, check for responsiveness and normal breathing. If the person is unresponsive and not breathing normally, begin CPR immediately and deploy an automated external defibrillator (AED) as soon as available.
6. If the person is breathing, position them safely, treat thermal burns by cooling with clean water, keep them still to protect potential spinal injuries from falls, and ensure they receive emergency hospital evaluation even if they feel uninjured.

Electrical emergency rescue flowchart¶

                   PERSON IN CONTACT WITH ELECTRICAL SOURCE
                                     │
                     Is it a HIGH-VOLTAGE source (> 1000V)
                     or a downed overhead utility line?
                                     │
                    ┌────────────────┴────────────────┐
                   YES                                NO
                    │                                 │
           ┌────────┴────────┐               ┌────────┴────────┐
           │   HIGH VOLTAGE  │               │   LOW VOLTAGE   │
           │  CRITICAL ZONE  │               │ (Household / AC)│
           └────────┬────────┘               └────────┬────────┘
                    │                                 │
        1. Keep 10m (33ft) perimeter         1. Switch off main breaker
        2. DO NOT approach or touch          2. Unplug if safe
        3. Call emergency + utility          3. If switch inaccessible:
        4. If trapped in vehicle:               use dry wooden broom or
           STAY INSIDE unless fire              fiberglass pole to pry
        5. If jumping clear:                    wire away from victim
           both feet together,               4. Stand on dry rubber / wood
           bunny-hop shuffle away                     │
                    │                        Contact broken safely
                    └────────────────┬────────────────┘
                                     │
                        Is the victim responsive and
                        breathing normally?
                                     │
                    ┌────────────────┴────────────────┐
                   YES                                NO
                    │                                 │
           ┌────────┴────────┐               ┌────────┴────────┐
           │  MONITOR VITALS │               │ CARDIAC ARREST  │
           └────────┬────────┘               └────────┬────────┘
                    │                                 │
        1. Maintain spinal neutral           1. Begin high-quality CPR
        2. Cool burns with water             2. Attach AED immediately
        3. Keep warm (shock care)            3. Follow AED prompts
        4. Mandatory ER telemetry            4. Continue until EMS takes over

Physics of electrical injury: AC versus DC¶

The nature and severity of electrical trauma depend directly on the type of electrical current, voltage level, pathway through the body, and duration of contact.

       ELECTRICAL CURRENT CHARACTERISTICS AND HUMAN TISSUE RISKS
┌──────────────────────┬──────────────────────┬──────────────────────┐
│ Parameter            │ Alternating Current  │ Direct Current (DC)  │
│                      │ (AC - 50/60 Hz)      │                      │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Common sources       │ Residential outlets, │ Batteries, solar,    │
│                      │ commercial mains     │ subways, lightning   │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Muscle response      │ Continuous tetany    │ Violent single spasm │
│                      │ ("No-let-go" grip)   │ (Throws victim away) │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Cardiac hazard       │ Ventricular          │ Asystole (cardiac    │
│                      │ Fibrillation (VF)    │ standstill)          │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Relative lethality   │ 3 to 5 times more    │ Requires higher      │
│                      │ lethal at low volts  │ voltage for VF risk  │
└──────────────────────┴──────────────────────┴──────────────────────┘

Alternating Current (AC) and flexor tetany¶

Household electrical power operates as alternating current at frequencies of 50 Hz (Europe, Asia, Africa) or 60 Hz (North America). - The "No-let-go" threshold: The human hand flexor muscles are substantially stronger than extensor muscles. When AC voltage passes through a person arm, the 50 to 60 cycle alternating current triggers rapid involuntary muscle contractions (tetany). This locks the fingers into a clenched fist around the conductor, physically preventing the victim from letting go of the live wire. - Thoracic tetany: Prolonged contact causes tetanic contraction of the diaphragm and intercostal muscles, inducing mechanical asphyxiation and respiratory arrest even before cardiac arrest occurs. - Low-voltage vulnerability: At residential voltages (120V to 240V), AC current precisely matches the vulnerable repolarization phase of myocardial tissue (the T-wave on an electrocardiogram), triggering lethal ventricular fibrillation with currents as low as 50 to 100 milliamperes.

Direct Current (DC) mechanics¶

Direct current flows continuously in a single direction. - Massive single muscle contraction: High-voltage DC contact typically produces a massive, sudden muscle convulsion that throws the victim violently backward away from the conductor. While this breaks electrical contact automatically, the kinetic energy frequently causes severe blunt trauma, including pelvic fractures, skull fractures, and traumatic spinal cord transection. - Cardiac standstill: DC current tends to paralyze the entire myocardium simultaneously, producing complete cardiac standstill (asystole) rather than ventricular fibrillation.

Low voltage versus high voltage classifications¶

Emergency medicine and electrical safety codes categorize electrical contact into two distinct operational zones:

High voltage hazards: downed lines and step potential¶

High-voltage electricity (greater than 1,000 volts) behaves fundamentally differently from household power. High-voltage current can ionize air, jumping or arcing across open physical space up to several meters without physical contact. Rescuers must never approach a high-voltage wire using household wooden broomsticks or plastic poles; high-voltage current readily bridges non-conductive materials and arcs directly into the rescuer body.

Step potential physics¶

When an energized power line falls to the ground, high-voltage current dissipates outward into the surrounding soil in concentric, ripple-like electrical gradients, similar to waves created by dropping a stone into water. - The voltage gradient: The electrical potential is highest directly beneath the fallen wire and decreases progressively as distance from the wire increases. - The danger to walking rescuers: If a person takes normal strides within this energized zone, one foot touches a point of higher electrical voltage while the other foot touches a point of lower electrical voltage. This difference in voltage between the feet is known as step potential. - Circuit through the body: The electrical differential drives current directly up one leg, across the pelvis, through vital reproductive and abdominal organs, and down the other leg into the earth. This causes sudden ventricular fibrillation, pelvic muscle tetany, or instantaneous collapse.

                    STEP POTENTIAL VOLTAGE GRADIENT
                           [ Fallen Wire ]
                              4,000 V
                             /       \
                        2,500 V     2,500 V
                       /                   \
                  1,000 V                 1,000 V
                 /                               \
              [Foot A: 1,500V]           [Foot B: 800V]
                     ▲                         │
                     └──── CURRENT FLOWS ──────┘
                          THROUGH PELVIS

The bunny-hop and shuffle escape technique¶

If you are caught near a downed power line or an electrical substation failure: 1. Establish a minimum perimeter: Remain at least 10 meters (33 feet) away from the fallen line in all directions. If the ground is wet, the line is arcing or hissing, or humidity is high, increase the perimeter to 20 meters (65 feet). 2. Never take normal walking strides: Never lift one foot off the ground while the other is extended. 3. The shuffle method: Place both feet touching each other side by side. Slide your feet forward slowly across the soil, keeping both soles in continuous contact with the earth. Never allow the heel of one foot to slide past the toe of the adjacent foot. Move by mere centimeters at a time until you are outside the 10-meter perimeter. 4. The bunny-hop method: If the ground is uneven, press your knees, ankles, and feet tightly together so they touch continuously. Hop with both feet leaving and landing on the ground at the exact same physical instant. Because both feet touch points of identical voltage potential simultaneously, no circuit can form across your body.

Vehicle in contact with live power lines¶

If a vehicle strikes a utility pole and an energized line collapses across the car roof or hood: - The safest place is inside: The vehicle metal frame and rubber tires function as a protective Faraday cage, channeling current around the perimeter of the passenger compartment into the earth. The occupants are entirely safe as long as they stay inside and do not touch exterior metal components. - Instruct occupants to stay put: Warn drivers and passengers never to step out of the car. Call the power utility and emergency services to de-energize the grid. - Emergency evacuation protocol for vehicle fire: If the vehicle catches fire and occupants must evacuate to avoid burning alive: 1. Open the vehicle door fully without touching the metal exterior frame. 2. Stand on the door sill without touching the ground. 3. Jump cleanly away from the vehicle with both arms crossed over your chest. 4. Land with both feet firmly together, ensuring zero contact between your body, the car, and the earth at the same moment. 5. Shuffle or bunny-hop away for at least 10 meters (33 feet).

Clinical pathology: the iceberg effect and internal burns¶

The most dangerous clinical aspect of an electric shock is the iceberg effect: superficial external skin wounds grossly underrepresent the catastrophic destruction occurring inside deep anatomical structures.

Tissue resistance hierarchy¶

As electrical current navigates through the human body, it follows Ohm law (\(V = IR\)) and Joule law of heating (\(Q = I^2 R t\)). Thermal energy generation is proportional to tissue resistance and current density:

               TISSUE RESISTANCE AND SUSCEPTIBILITY MATRIX
┌──────────────────────┬──────────────────────┬──────────────────────┐
│ Tissue Type          │ Relative Resistance  │ Clinical Effect      │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Bone                 │ Highest Resistance   │ Acts as resistor;    │
│                      │                      │ heats to extreme temp│
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Fat and Skin         │ High Resistance      │ Local entrance and   │
│                      │                      │ exit puncture burns  │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Skeletal Muscle      │ Moderate Resistance  │ Massive necrosis     │
│                      │                      │ from heated bone     │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Blood Vessels        │ Low Resistance       │ Thrombosis, ischemic │
│                      │ (High Water/Salt)    │ loss of limb digits  │
├──────────────────────┼──────────────────────┼──────────────────────┤
│ Nerves               │ Lowest Resistance    │ Immediate conduction │
│                      │ (Optimal Conductor)  │ block, neuropathies  │
└──────────────────────┴──────────────────────┴──────────────────────┘

Because compact bone exhibits the highest electrical resistance, it acts as a massive thermal heating element. As current traverses an extremity, the central bone heats to extreme temperatures, effectively cooking deep periosteal muscle layers from the inside outward. A patient with normal-looking superficial skin may harbor dead, liquefied deep muscle compartments beneath.

Acute compartment syndrome¶

As deep muscle tissue undergoes thermal necrosis, cellular membranes rupture, causing massive interstitial edema (swelling) within rigid, non-expanding muscular fascial compartments of the arms and legs. - Pressure elevation: Compartment pressure rapidly exceeds capillary perfusion pressure, cutting off all arterial blood flow to distal tissues. - Surgical emergency: The patient develops excruciating pain out of proportion to exam findings, pallor, pulselessness, and numbness. Immediate surgical fasciotomy (cutting open the full length of the limb fascia) is mandatory within hours to prevent total limb amputation.

Rhabdomyolysis and acute kidney failure¶

When extensive skeletal muscle tissue is destroyed by electrical current, dead myocytes release massive volumes of intracellular myoglobin, creatine phosphokinase (CPK), and potassium into the systemic bloodstream. - The tea-colored urine warning: Circulating myoglobin precipitates within renal tubules, forming obstructive casts that cause acute tubular necrosis. The cardinal clinical indicator of rhabdomyolysis is dark brown, tea-colored, or cola-colored urine produced hours after the shock. - Hyperkalemia: Massive potassium release from ruptured cells disrupts cardiac pacing, triggering secondary ventricular arrhythmias hours after the initial shock. - Action: Patients require aggressive intravenous hydration with isotonic crystalloids (lactated Ringer or normal saline) managed by a hospital trauma burn unit to maintain urine output of 1 to 2 milliliters per kilogram per hour.

Cardiac monitoring and resuscitation protocols¶

Any shock that passes through the thorax (such as hand-to-hand or hand-to-foot pathways) can disrupt cardiac rhythm.

CPR in electrical cardiac arrest¶

If an electrical shock victim is in cardiac arrest: - Resuscitation success rates: Survival rates from electrical cardiac arrest are significantly higher than from normothermic medical cardiac arrest, provided CPR is started immediately. Healthy young individuals often have reversible ventricular fibrillation or temporary asystole with undamaged underlying coronary arteries. - Defibrillation: Turn on the automated external defibrillator (AED) immediately. Deliver shocks for ventricular fibrillation or pulseless ventricular tachycardia without delay. - Prolonged CPR doctrine: High-voltage electrical shocks can stun the central brainstem respiratory center for hours while myocardial function recovers. Responders must continue high-quality CPR and positive pressure ventilations until hospital arrival, as neurologically intact recoveries are well documented following prolonged resuscitation in electrical trauma.

Indications for mandatory 24-hour cardiac telemetry¶

Every individual who experiences an electric shock, excluding trivial static electricity discharges, must undergo an emergency medical examination. Hospital admission and continuous 24-hour cardiac monitoring are mandatory if the patient meets any of the following clinical criteria: - Any witnessed or suspected loss of consciousness - Documented history of cardiac arrest or abnormal rhythm at the scene - Any abnormality detected on initial hospital 12-lead electrocardiogram (ECG) - Contact with high-voltage sources (> 1,000V) - Evident full-thickness entrance or exit burns - Presence of chest pain, palpitations, shortness of breath, or dizziness - Pre-existing cardiovascular disease or current pregnancy

First aid burn care for electrical contact wounds¶

1. Check for entrance and exit points: Search the entire body for electrical contact marks, particularly on the palms, fingertips, feet, toes, and scalp.
2. Cool the wounds: Cool contact burns using clean, cool running water for 20 minutes to halt thermal progression. Never apply ice, ice water, butter, ointments, or adhesive bandages.
3. Dress loosely: Cover the wounds with sterile dry non-adherent gauze, clean linen, or plastic cling film applied loosely. Never wrap burns tightly, as rapid tissue swelling will create a tourniquet effect.
4. Protect the cervical spine: If the victim fell from a ladder, was thrown across the room by a DC jolt, or was blown back by an arc flash, assume cervical spine and musculoskeletal fractures. Do not move or twist their neck unless immediate fire or electrical hazards threaten life.

Electrical prevention and home safety checklist¶

• Test Ground Fault Circuit Interrupters (GFCIs) monthly: Press the test and reset buttons on all bathroom, kitchen, and outdoor outlets.
• Inspect electrical cords: Immediately discard cords with cracked insulation, exposed copper strands, or loose plug prongs.
• Never overload multi-socket extensions: Heavy heating appliances (space heaters, air conditioners, toasters) must be plugged directly into dedicated wall sockets.
• Childproof residential outlets: Install spring-loaded tamper-resistant receptacle covers or plastic safety caps in homes with toddlers.
• Call before you dig: Contact municipal utility locator services (such as 811 in the United States) before digging trenches, fence posts, or planting trees to avoid underground high-voltage power conduits.
• Maintain clearance around overhead lines: When carrying aluminum extension ladders, tree pruning poles, or pool skimmers, look upward and maintain a minimum 3-meter (10-foot) clearance from overhead service lines.

Frequently asked questions¶

Why is alternating current (AC) more dangerous than direct current (DC) in household settings?¶

Alternating current at 50 or 60 Hz causes continuous muscle spasms (tetany) in the hands and arms, locking a person fingers around the live wire so they cannot let go. This continuous exposure dramatically increases internal tissue cooking. Furthermore, 50 to 60 Hz current easily disrupts the electrical pacing of the human heart, triggering lethal ventricular fibrillation even at low residential voltages.

Can an electric shock cause serious damage even if the skin looks unburned?¶

Yes. Electricity travels along the path of least resistance inside the body, passing through deep nerves, blood vessels, and muscles. The intense electrical resistance of bone also causes it to heat up, burning surrounding deep muscle from the inside out while surface skin remains largely intact. Serious cardiac rhythm disturbances, internal nerve damage, and kidney failure from muscle breakdown can develop hours later without visible surface burns.

What should I do if someone is being shocked by a household appliance and I cannot find the breaker?¶

Do not touch the victim directly with your bare hands. Stand on a dry, non-conductive surface such as a dry wooden board, rubber mat, or thick stack of paper. Use a completely dry, non-conductive object made of clean wood, thick plastic, or fiberglass (such as a wooden broomstick or plastic chair) to push the appliance or electrical wire away from the victim, or push the victim away from the source.

Why is walking near a downed power line dangerous even if I do not touch the wire?¶

When a high-voltage power line hits the ground, electricity fans outward through the soil in concentric rings of decreasing voltage. If you walk normally, your feet land on two different voltage rings. This difference in electrical potential (step potential) forces electrical current to travel up one leg, through your pelvis, and down the other leg, causing immediate collapse or cardiac arrest. You must keep your feet pressed together and shuffle or hop away.

When does someone who received an electric shock need to go to the hospital?¶

Anyone who experienced an electric shock should be evaluated by a healthcare professional unless it was a trivial static shock. Immediate emergency room evaluation with continuous electrocardiogram (ECG) telemetry is mandatory if the person lost consciousness, touched a high-voltage wire (> 1,000V), has entrance or exit burns, experienced a fall, or has chest pain, palpitations, numbness, or dark brown urine.

Related guides¶

• Burn classification and first aid
• Cardiopulmonary resuscitation (CPR)
• Electrical fire and sparks
• Thunderstorms and lightning safety
• Emergency phone numbers by country