Electric shock is what happens when electrical current passes through your body. It can range from a barely noticeable tingle to a life-threatening event, depending on how much current flows, how long it lasts, and what path it takes through your tissues. The threshold you can feel starts at just 0.2 milliamperes, while currents above 50 milliamperes can stop your heart.
How Electricity Moves Through Your Body
Your body conducts electricity because your internal tissues are wet and salty, giving them a relatively low electrical resistance of about 300 ohms. What stands between you and a dangerous current is mostly your skin. Dry, calloused skin can have a resistance above 100,000 ohms, which severely limits how much current gets through. Normal skin contact resistance falls somewhere between 1,000 and 100,000 ohms depending on moisture, skin condition, and the size of the contact area.
This is why water makes electric shock so much more dangerous. Wet skin, cuts, deep abrasions, or full immersion can bypass your skin’s protective resistance almost entirely. When you’re submerged in water, your total body resistance from hand to foot drops to around 300 ohms. At that level, even a relatively low voltage can push a lethal amount of current through you. It’s the same basic principle behind all electrical flow: higher voltage and lower resistance means more current, and current is what does the damage.
What Determines How Severe a Shock Is
The severity of an electric shock depends on four main factors: the amount of current, the duration of contact, the path through the body, and the type of current.
- 0.2 to 1 milliampere: You feel a tingling sensation. This is the threshold of perception.
- 10 to 16 milliamperes: Your muscles contract involuntarily, and you may not be able to release your grip on the electrical source. This is called the “let-go” threshold.
- 50 to 100 milliamperes: Serious physiological effects begin, including cardiac arrest, breathing failure, and burns. The probability of a fatal heart rhythm called ventricular fibrillation increases with both the current level and the duration. After two seconds of exposure in this range, the chance of fibrillation approaches 50%.
- Above 60 milliamperes: Heart fibrillation and significant electrical burns become likely.
The path the current takes matters enormously. A shock that travels hand to hand passes directly through the chest, putting the heart at risk. A shock confined to a single finger is far less likely to be fatal, even at the same current level.
AC vs. DC Current
Alternating current (AC), the type that comes out of household outlets, is generally more dangerous than direct current (DC) at the same voltage. AC rapidly reverses direction, which causes your muscles to contract and relax repeatedly. This can produce a state called tetany, where muscles lock up and you physically cannot let go of the electrical source. DC typically causes a single forceful contraction that may actually throw you away from the source. The let-go threshold for DC is higher than for AC, meaning you can tolerate more DC current before losing muscle control.
Types of Electrical Injury
Not all electrical injuries work the same way. True electrical injuries happen when your body becomes part of the circuit, with current entering at one point and exiting at another. These are the most dangerous because current flows through internal tissues. Flash injuries come from an arc flash, a burst of intense heat and light that causes surface burns without current actually passing through the body. Flame injuries occur when the electrical event ignites clothing or nearby materials, causing conventional burns.
One of the most deceptive aspects of electrical injury is that surface burns don’t reliably indicate what’s happening inside. High skin resistance causes more energy to dissipate at the skin surface, producing visible burns but sparing deeper tissues. Low skin resistance does the opposite: minimal or no visible marks on the outside, while electrical energy penetrates to internal tissues. Inside the body, high-energy current can destroy proteins, cause tissue death, rupture blood cells, trigger blood clots, and damage muscles and tendons. This means someone with no apparent burns can still have severe internal injuries.
Long-Term Effects of Electrical Injury
Surviving a serious electric shock doesn’t necessarily mean a full recovery. Permanent nerve damage at the site where current entered the body is extremely common. Many survivors develop problems in one or more peripheral nerves, leading to chronic pain, numbness, or weakness. Cognitive effects are also well documented: deficits in verbal memory, executive functioning, and attention appear consistently in people who’ve experienced significant electrical injury.
The psychological toll can be just as severe. As many as 78% of people who experience a significant electrical injury go on to develop a psychiatric diagnosis. Depression and PTSD are particularly common, especially among those who experienced the “no-let-go” phenomenon, where involuntary muscle contraction trapped them on the electrical source. Loss of consciousness or being thrown from the source also correlates with higher rates of depression and PTSD. Two years after an electrical accident, survivors are 14 times more likely to have a psychiatric diagnosis than people who suffered traumatic brain injury or other types of burns.
Behavioral changes like irritability, frustration, anger, and physical aggression have been described in people with no prior mood or personality disorders. Perhaps most concerning, these consequences can be substantially delayed, appearing one to five or more years after the original injury.
Common Sources of Electric Shock
Most non-occupational electric shocks happen at home or around the yard. Faulty wiring, damaged power cords, malfunctioning appliances, and using electrical equipment in wet conditions are the most common culprits. Power tools that develop internal shorts are a frequent source of injury, particularly when used outdoors or in damp environments.
Ground fault circuit interrupters (GFCIs), the outlets with “test” and “reset” buttons you see in bathrooms and kitchens, are specifically designed to prevent shock. They detect when current is leaking along an unintended path (like through your body) and cut the power in about 1/40th of a second, fast enough to prevent serious injury in most cases. GFCI protection is essential anywhere electrical devices are used outdoors or in wet or damp locations. Workplace safety standards from OSHA require protective measures for anyone working near uninsulated parts operating at 50 volts or more.
What to Do If Someone Is Being Shocked
If you see someone in contact with an electrical source, do not touch them. Their body is conducting current, and you’ll become part of the circuit. Turn off the power source if you can reach it safely. If you can’t, use a dry, non-conducting object (cardboard, plastic, or wood) to separate the person from the source.
Don’t move someone with an electrical injury unless they’re in immediate danger, since falls or muscle contractions during the shock may have caused spinal or bone injuries. If the person isn’t breathing, coughing, or showing any signs of circulation, begin CPR while waiting for emergency help.