Electricity is the lifeblood of modern society, and you know how insanely dangerous it can get. In the United States, more than 100 people die each year from electrocution and about another 60 electrocutions occur from consumer products like power tools and lighting equipment. You are well aware that electricity can hurt and even kill you. But do you know what exactly happens to your body when you get an electric shock or get electrocuted? Here’s what Life Noggin explains.
Engineers and scientists use volts and amperes (amps) to describe the electrical phenomena of the world. Ampere is the unit of electric current and it measures current flow, or how much electric charge flows through a point per unit of time.
Electrocution happens when you come into contact with a current of around 1 mA (milliampere). When you get electrocuted, it’s actually the moving electrons in you, creating a ‘current’, and these moving electrons are what typically cause harm to a person through tissue or nervous system damage. What these electrons actually do is that they will flow through your body in ways they aren’t typically supposed to, and as a result they cause damages inside your body which includes – burning of bodily tissues and interfering with essential electrical signals that your body use to send signals between your nerves including muscle fibers and neurons.
The Occupational Safety and Health Administration (OSHA) issues some guidelines regarding hazards associated with electricity. The table shows intensity of current and its effect on person.
Current (mA) Effect On Person
0.5 to 3 mA – Tingling sensations
3 to 10 mA – Muscle contractions and pain
10 to 40 mA – “Let-go” threshold
30 to 75 mA – Respiratory paralysis
100 to 200 mA – Ventricular fibrillation (may lead to death)
200 to 500 mA – Heart clamps tight
Above 1500 mA – Tissue and organs start to burn
Also, there are three basic types of burns, as explained by OSHA:
1. Electrical burns – These are caused due to the current flowing in the tissues, and may affect the skin, muscles and bones. Tissue damage is generally caused by the heat generated from the current flow. As the current passes through your body, your body acts as a resistor in a circuit. Hence, it creates heat. And if the energy delivered by the electric shock is high, your tissue will suffer severe burns as your body cannot dissipate the heat.
2. Arc burns: These are caused by high temperatures generated by electric arcs or by explosions close to your body.
3. Thermal contact burns: These are the type of burns you get when you contact hot surfaces of overheated electric conductors, conduits, or other energized equipment.
Life Noggin explains that a small current could travel from one arm, directly through the heart, and to the other arm and cause a person to die. This is one of the most common causes of fatality and is known as ventricular fibrillation. Also at the same time, an extremely large current from a lightning bolt could hit a person and only cause bodily burns.
The severity and effects of electric shock depend on the intensity of the current and where it passes through the body. Certain body parts are more susceptible to electric damage than others, with someone’s internal organs having far less resistance than their outer skin.
Not everyone has the same electrical resistance. For example, like the resistors used in electronic devices, the resistance of a person’s arm depends on its length and diameter. Resistance goes up with length and down with diameter. Men have lower resistance than women because of thicker arms and legs. Moreover, wet skin also has way less resistance (1000 Ohms or less) than dry skin (100,000 Ohms). This is why, the current in wet skin can be several times greater than the current in dry skin. So, when water is involved, you’re at far greater risks of electrocution.
A high amount of electricity going through you is usually bad, but there is a thing called defibrillator where a little electric kiss can be a good thing. Defibrillator delivers a therapeutic dose of electrical energy to a person’s heart in order to treat urgent medical conditions like sudden cardiac arrest. Sudden cardiac arrest is usually caused by ventricular fibrillation, and without the use of CPR (cardiopulmonary resuscitation) and defibrillator, it can lead to death.
You may also ask why birds don’t get electrocuted even if they sit on high-voltage power lines. Well, electrical current is the movement of electrons, and one thing that electrons need in order to move is the electrical potential difference. When a bird sits on a single wire, its two feet are at the same electrical potential, so the electrons in the wires won’t move and hence there will be no current flowing through the bird’s body. This is the reason why birds don’t get electrocuted. However, if that bird stretches out its other leg or wing and touches a second wire, especially one with a different electrical potential, it will open a path for the electrons, then that bird will get roasted.