Electrical injury is a physiological reaction caused by
electric current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...
passing through the body.
The injury depends on the density of the current, tissue resistance and duration of contact. Very small currents may be imperceptible or produce a light tingling sensation. A shock caused by low and otherwise harmless current could startle an individual and cause injury due to jerking away or falling. Stronger currents may cause some degree of discomfort or pain, while more intense currents may induce involuntary muscle contractions, preventing the person from breaking free of the source of electricity. Still larger currents result in tissue damage and may trigger
ventricular fibrillation
Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver. It is due to disorganized electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and no p ...
or
cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...
. Consequences of injury from electricity may include amputations, bone fractures and orthopedic and musculoskeletal injuries. If death results from an electric shock the
cause of death
In law, medicine, and statistics, cause of death is an official determination of conditions resulting in a human's death, which may be recorded on a death certificate. A cause of death is determined by a medical examiner. The cause of death is ...
is generally referred to as
electrocution
Electrocution is death or severe injury caused by electric shock from electric current passing through the body. The word is derived from "electro" and "execution", but it is also used for accidental death.
The term "electrocution" was coined ...
.
Electric injury occurs upon contact of a body part with
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
that causes a sufficient current to pass through the person's tissue. Contact with energized
wiring
Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure.
Wiring is subject to safety standards for design and installation. Allowable ...
or devices is the most common cause. In cases of exposure to high
voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
s, such as on a
power transmission tower
A transmission tower, also known as an electricity pylon or simply a pylon in British English and as a hydro tower in Canadian English, is a tall structure, usually a steel lattice tower, used to support an overhead power line.
In electrical gri ...
, direct contact may not be necessary as the voltage may
"jump" the air gap to the electrical device.
Following an electrical injury from household current, if a person has no symptoms, no underlying heart problems, and is not pregnant further testing is not required.
[ Otherwise an electrocardiogram, blood work to check the heart, and urine testing for signs of muscle breakdown may be performed.]
Management may involve resuscitation
Resuscitation is the process of correcting physiological disorders (such as lack of breathing or heartbeat) in an acutely ill patient. It is an important part of intensive care medicine, anesthesiology, trauma surgery and emergency medicine. W ...
, pain medications, wound management, and heart rhythm monitoring.[ Electrical injuries affect more than 30,000 people a year in the United States and result in about 1,000 deaths.]
Signs and symptoms
Burns
Heating due to resistance can cause extensive and deep burn
A burn is an injury to skin, or other tissues, caused by heat, cold, electricity, chemicals, friction, or ultraviolet radiation (like sunburn). Most burns are due to heat from hot liquids (called scalding), solids, or fire. Burns occur mainl ...
s. When applied to the hand, electricity can cause involuntary muscle contraction, producing the "no-let-go" phenomenon, and increasing the risk for serious burns. Voltage levels of 500 to 1000 volts tend to cause internal burns due to the large energy (which is proportional to the duration multiplied by the square of the voltage divided by resistance) available from the source. Damage due to current is through tissue heating and/or electroporation injury. For most cases of high-energy electrical trauma, the Joule heating in the deeper tissues along the extremity will reach damaging temperatures in a few seconds.
Ventricular fibrillation
A domestic power supply voltage (110 or 230 V), 50 or 60 Hz alternating current
Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
(AC) through the chest for a fraction of a second may induce ventricular fibrillation
Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver. It is due to disorganized electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and no p ...
at currents as low as 30 milliamperes (mA). With direct current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
(DC), 300 to 500 mA is required.[ If the current has a direct pathway to the heart (e.g., via a cardiac catheter or other kind of ]electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...
), a much lower current of less than 1 mA (AC or DC) can cause fibrillation. If not immediately treated by defibrillation
Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''cou ...
, ventricular fibrillation is usually lethal, causing cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...
, because all of the heart muscle fibres move independently instead of in the coordinated action needed for successful cardiac cycle
The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following ...
to pump blood and maintain circulation. Above 200 mA, tetanic muscle contractions are so strong that the heart muscles cannot move at all, but these conditions prevent fibrillation.
Mechanism
Mechanism of cardiac arrhythmias induced by electricity is not fully understood, but various biopsies have shown arrhythmogenic foci in patchy myocardial fibrosis
Cardiac fibrosis commonly refers to the excess deposition of extracellular matrix in the cardiac muscle, but the term may also refer to an abnormal thickening of the heart valves due to inappropriate proliferation of cardiac fibroblasts. Fibrotic c ...
which contained increased amount of Na+ and K+ pumps
A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...
, possibly associated with transient and localized changes in sodium-potassium transport as well as their concentrations, resulting in changes in membrane potential
Membrane potential (also transmembrane potential or membrane voltage) is the difference in electric potential between the interior and the exterior of a biological cell. That is, there is a difference in the energy required for electric charges ...
.
Neurological effects
Electrical current can cause interference with nervous control, especially over the heart and lungs. Electric shock which does not lead to death has been shown to cause neuropathy
Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or o ...
at the site where the current entered the body. The neurologic symptoms of electrical injury may occur immediately, which traditionally have a higher likelihood for healing, though they may also be delayed by days to years. The delayed neurologic consequences of electrical injury have a worse prognosis
Prognosis (Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain stabl ...
.
When the path of electrical current proceeds through the head, it appears that, with sufficient current applied, loss of consciousness almost always occurs swiftly. This is borne out by some limited self-experimentation
Self-experimentation refers to the special case of single-subject research in which the experimenter conducts the experiment on themselves.
Usually this means that a single person is the designer, operator, subject, analyst, and user or reporter ...
by early designers of the electric chair
An electric chair is a device used to execute an individual by electrocution. When used, the condemned person is strapped to a specially built wooden chair and electrocuted through electrodes fastened on the head and leg. This execution method, ...
and by research from the field of animal husbandry
Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, selective breeding, and the raising of livestock. Husbandry has a long history, starti ...
, where electric stunning
Stunning is the process of rendering animals immobile or unconscious, with or without killing the animal, when or immediately prior to slaughtering them for food.
Rationale
Within the European Union, most animals slaughtered for human consumpt ...
has been extensively studied.
If ventricular fibrillation occurs (as above), the blood supply to the brain is diminished, which may cause cerebral hypoxia
Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called ''cerebral anoxia''. There are four categories of cerebral hypoxia; they are, in o ...
(and its associated neurologic consequences).
Mental health
There are a variety of psychiatric effects that may occur as a result of electrical injuries. Behavioral changes can occur as well, even if the path of electrical current did not proceed through the head. Symptoms may include:
* Depression, including feelings of low self-esteem and guilt
*Anxiety
Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
spectrum disorders, including posttraumatic stress disorder
Post-traumatic stress disorder (PTSD) is a mental and behavioral disorder that can develop because of exposure to a traumatic event, such as sexual assault, warfare, traffic collisions, child abuse, domestic violence, or other threats on ...
and fear of electricity
*Moodiness, including a lower threshold for frustration and "losing one's temper"
*Memory loss, decreased attention span, and difficulty learning
Arc-flash hazards
OSHA
OSHA or Osha may refer to:
Work
* Occupational Safety and Health Administration, a federal agency of the United States that regulates workplace safety and health
* Occupational Safety and Health Act (United States) of 1970, a federal law in the Un ...
found that up to 80 percent of its electrical injuries involve thermal burns due to arcing faults. The arc flash in an electrical fault produces the same type of light radiation
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:
* ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...
from which electric welders protect themselves using face shields with dark glass, heavy leather gloves, and full-coverage clothing. The heat produced may cause severe burns, especially on unprotected flesh. The arc blast produced by vaporizing metallic components can break bones and damage internal organs. The degree of hazard present at a particular location can be determined by a detailed analysis of the electrical system, and appropriate protection worn if the electrical work must be performed with the electricity on.
Pathophysiology
The minimum current a human can feel depends on the current type ( AC or DC) as well as frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
for AC. A person can sense electrical current as low as 1 mA ( rms) for 60Hz AC and as low as 5mA for DC. At around 10mA, DC current passing through the arm of a human can cause powerful muscle contractions; the victim is unable to voluntarily control muscles and cannot release an electrified object. This is known as the "let go threshold" and is a criterion for shock hazard in electrical regulations.
The current may, if it is high enough and is delivered at sufficient voltage, cause tissue damage or fibrillation
Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with regard to the heart.
Cardiology
There are two major classes of cardiac fibrillation: atrial fibrillation and ventricular fib ...
which can cause cardiac arrest; [ucsb.edu - Electrical Safety Information - Physics Department, UCSB]
, 2012-01-09 of AC (rms, 60 Hz) or of DC at high voltage can cause fibrillation.[Clifford D. Ferris, ''Electric Shock'', chapter 22.1 in Jerry C. Whitaker (ed.) ''The Electronics Handbook'', CRC Press, 2005, , pp. 2317-2324] A sustained electric shock from AC at 120 V, 60 Hz is an especially dangerous source of ventricular fibrillation
Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver. It is due to disorganized electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and no p ...
because it usually exceeds the let-go threshold, while not delivering enough initial energy to propel the person away from the source. However, the potential seriousness of the shock depends on paths through the body that the currents take.[ If the ]voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
is less than 200 V, then the human skin, more precisely the stratum corneum
The stratum corneum (Latin for 'horny layer') is the outermost layer of the epidermis. The human stratum corneum comprises several levels of flattened corneocytes that are divided into two layers: the ''stratum disjunctum'' and ''stratum compact ...
, is the main contributor to the impedance of the body in the case of a macroshock Macroshock (mak´ro-shok″) is a medical term for the effects of body exposed to electrical current, which can lead to severe injury or death by electrocution. It is used most often in the medical field, but is also commonly used in the fields of e ...
—the passing of current between two contact points on the skin. The characteristics of the skin are non-linear however. If the voltage is above 450–600 V, then dielectric breakdown
Electrical breakdown or dielectric breakdown is a process that occurs when an electrical insulating material, subjected to a high enough voltage, suddenly becomes an electrical conductor and electric current flows through it. All insulating mate ...
of the skin occurs. The protection offered by the skin is lowered by perspiration
Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals.
Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distrib ...
, and this is accelerated if electricity causes muscles to contract above the let-go threshold for a sustained period of time.[
If an electrical circuit is established by electrodes introduced in the body, bypassing the skin, then the potential for lethality is much higher if a circuit through the heart is established. This is known as a ]microshock
Microshock refers to the risk that patients undergoing medical procedures involving externally protruding intracardiac electrical conductors, such as external pacemaker electrodes, or saline filled catheters, could suffer an electric shock causin ...
. Currents of only 10 µA can be sufficient to cause fibrillation in this case with a probability of 0.2%.
Body resistance
The voltage necessary for electrocution depends on the current through the body and the duration of the current. Ohm's law
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equat ...
states that the current drawn depends on the resistance of the body. The resistance of human skin varies from person to person and fluctuates between different times of day. The NIOSH
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
states "Under dry conditions, the resistance offered by the human body may be as high as 100,000 ohms. Wet or broken skin may drop the body's resistance to 1,000 ohms," adding that "high-voltage electrical energy quickly breaks down human skin, reducing the human body's resistance to 500 ohms".
The International Electrotechnical Commission
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
gives the following values for the total body impedance of a hand to hand circuit for dry skin, large contact areas, 50 Hz AC currents (the columns contain the distribution of the impedance in the population percentile
In statistics, a ''k''-th percentile (percentile score or centile) is a score ''below which'' a given percentage ''k'' of scores in its frequency distribution falls (exclusive definition) or a score ''at or below which'' a given percentage falls ...
; for example at 100 V 50% of the population had an impedance of 1875Ω or less):
Skin
The voltage-current characteristic of human skin is non-linear and depends on many factors such as intensity, duration, history, and frequency of the electrical stimulus. Sweat gland activity, temperature, and individual variation also influence the voltage-current characteristic of skin. In addition to non-linearity, skin impedance exhibits asymmetric and time varying properties. These properties can be modeled with reasonable accuracy. Resistance measurements made at low voltage using a standard ohmmeter
An analog ohmmeter
An ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multimeters also function as ohmmeters when in resistance-measu ...
do not accurately represent the impedance of human skin over a significant range of conditions.
For sinusoidal electrical stimulation less than 10 volts, the skin voltage-current characteristic is quasilinear. Over time, electrical characteristics can become non-linear. The time required varies from seconds to minutes, depending on stimulus, electrode placement, and individual characteristics.
Between 10 volts and about 30 volts, skin exhibits non-linear but symmetric electrical characteristics. Above 20 volts, electrical characteristics are both non-linear and symmetric. Skin conductance can increase by several orders of magnitude in milliseconds. This should not be confused with dielectric breakdown
Electrical breakdown or dielectric breakdown is a process that occurs when an electrical insulating material, subjected to a high enough voltage, suddenly becomes an electrical conductor and electric current flows through it. All insulating mate ...
, which occurs at hundreds of volts. For these reasons, current flow cannot be accurately calculated by simply applying Ohm's law
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equat ...
using a fixed resistance model.
Point of entry
* Macroshock Macroshock (mak´ro-shok″) is a medical term for the effects of body exposed to electrical current, which can lead to severe injury or death by electrocution. It is used most often in the medical field, but is also commonly used in the fields of e ...
: Current across intact skin and through the body. Current from arm to arm, or between an arm and a foot, is likely to traverse the heart, therefore it is much more dangerous than current between a leg and the ground. This type of shock by definition must pass into the body through the skin.
* Microshock
Microshock refers to the risk that patients undergoing medical procedures involving externally protruding intracardiac electrical conductors, such as external pacemaker electrodes, or saline filled catheters, could suffer an electric shock causin ...
: Very small current source with a pathway directly connected to the heart tissue. The shock is required to be administered from inside the skin, directly to the heart i.e. a pacemaker lead, or a guide wire, conductive catheter etc. connected to a source of current. This is a largely theoretical hazard as modern devices used in these situations include protections against such currents.
Lethality
Electrocution
The earliest usage of the term "electrocution" cited by the Oxford English Dictionary was an 1889 newspaper reference to the method of execution then being considered. Shortly thereafter, in 1892, the term was used in ''Science'' to refer generically to death or injury caused by electricity.
Factors in lethality of electric shock
The lethality of an electric shock is dependent on several variables:
* Current. The higher the current, the more likely it is lethal. Since current is proportional to voltage when resistance is fixed (ohm's law
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equat ...
), high voltage is an indirect risk for producing higher currents.
* Duration. The longer the duration, the more likely it is lethal—safety switches may limit time of current flow
* Pathway. If current flows through the heart muscle, it is more likely to be lethal.
* High voltage
High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, ''high voltage'' refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant spec ...
(over about 600 volts). In addition to greater current flow, high voltage may cause dielectric breakdown at the skin, thus lowering skin resistance and allowing further increased current flow.
* Medical implants
An implant is a medical device manufactured to replace a missing biological structure, support a damaged biological structure, or enhance an existing biological structure. Medical implants are man-made devices, in contrast to a transplant, whi ...
. Artificial cardiac pacemaker
An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a medical device that generates electrical impulses delivered by electrodes to the chambers of the heart ei ...
s or implantable cardioverter-defibrillator
An implantable cardioverter-defibrillator (ICD) or automated implantable cardioverter defibrillator (AICD) is a device implantable inside the body, able to perform defibrillation, and depending on the type, cardioversion and pacing of the ...
s (ICD) are sensitive to very small currents.
* Pre-existing medical condition.
* Age and sex.
Other issues affecting lethality are frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
, which is an issue in causing cardiac arrest or muscular spasms. Very high frequency electric current causes tissue burning, but does not penetrate the body far enough to cause cardiac arrest (see electrosurgery
Electrosurgery is the application of a high-frequency (radio frequency) alternating polarity, electrical current to biological tissue as a means to cut, coagulate, desiccate, or fulgurate tissue.Hainer BL, "Fundamentals of electrosurgery", ''Jou ...
). Also important is the pathway: if the current passes through the chest or head, there is an increased chance of death. From a main circuit or power distribution panel the damage is more likely to be internal, leading to cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...
. Another factor is that cardiac tissue has a chronaxie
Chronaxie is the minimum time required for an electric current double the strength of the rheobase to stimulate a muscle or a neuron. Rheobase is the lowest intensity with indefinite pulse duration which just stimulated muscles or nerves. Chronaxi ...
(response time) of about 3 milliseconds, so electricity at frequencies of higher than about 333 Hz requires more current to cause fibrillation than is required at lower frequencies.
The comparison between the dangers of alternating current
Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
at typical power transmission frequences (i.e., 50 or 60 Hz), and direct current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
has been a subject of debate ever since the war of the currents
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc ...
in the 1880s. Animal experiments conducted during this time suggested that alternating current was about twice as dangerous as direct current per unit of current flow (or per unit of applied voltage).
It is sometimes suggested that human lethality is most common with alternating current
Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
at 100–250 volts; however, death has occurred below this range, with supplies as low as 42 volts. Assuming a steady current flow (as opposed to a shock from a capacitor or from static electricity
Static electricity is an imbalance of electric charges within or on the surface of a material or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is na ...
), shocks above 2,700 volts are often fatal, with those above 11,000 volts being usually fatal, though exceptional cases have been noted. According to a Guinness Book of World Records
''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
comic, seventeen-year-old Brian Latasa survived a 230,000 volt shock on the tower of an ultra-high voltage line in Griffith Park
Griffith Park is a large municipal park at the eastern end of the Santa Monica Mountains, in the Los Feliz neighborhood of Los Angeles, California. The park includes popular attractions such as the Los Angeles Zoo, the Autry Museum of the Ameri ...
, Los Angeles on November 9, 1967. A news report of the event stated that he was "jolted through the air, and landed across the line", and though rescued by firemen, he sustained burns over 40% of his body and was completely paralyzed except for his eyelids. The shock with the highest voltage reported survived was that of Harry F. McGrew, who came in contact with a 340,000 volt transmission line in Huntington Canyon, Utah.
Prevention
* Grounding the electrical enclosure
An electrical enclosure is a cabinet for electrical or electronic equipment to mount switches, knobs and displays and to prevent electrical shock to equipment users and protect the contents from the environment. The enclosure is the only part ...
of high-voltage machinery.
*Use of insulated gloves, insulated boots, mats and tools.
*Protecting electrical circuit with a residual-current device
A residual-current device (RCD), residual-current circuit breaker (RCCB) or ground fault circuit interrupter (GFCI) is an electrical safety device that quickly breaks an electrical circuit with leakage current to ground. It is to protect equi ...
(RCD).
Epidemiology
There were 550 reported electrocutions in the US in 1993, 2.1 deaths per million inhabitants. At that time, the incidence of electrocutions was decreasing. Electrocutions in the workplace make up the majority of these fatalities. From 1980–1992, an average of 411 workers were killed each year by electrocution. Workplace deaths caused by exposure to electricity in the U.S. increased by nearly 24% between 2015 and 2019, from 134 to 166. However, workplace electrical injuries dropped 23% between 2015 and 2019 from 2,480 to 1,900. In 2019, the top 5 states with the most workplace electrical fatalities were: (1) Texas (608); (2) California (451); (3) Florida (306); (4) New York (273); and (5) Georgia (207).
A recent study conducted by the National Coroners Information System (NCIS) in Australia has revealed 321 closed case fatalities (and at least 39 case fatalities still under coronial investigation) that had been reported to Australian coroners where a person died from electrocution between July 2000 and October 2011.
In Sweden, Denmark, Finland and Norway the number of electric deaths per million inhabitants was 0.6, 0.3, 0.3 and 0.2, respectively, in the years 2007–2011.
People who survive electrical trauma may develop a host of injuries including loss of consciousness, seizures, aphasia, visual disturbances, headaches, tinnitus, paresis, and memory disturbances. Even without visible burns, electric shock survivors may be faced with long-term muscular pain and discomfort, exhaustion, headache, problems with peripheral nerve conduction and sensation, inadequate balance and coordination, among other symptoms. Electrical injury can lead to problems with neurocognitive function, affecting speed of mental processing, attention, concentration, and memory. The high frequency of psychological problems is well established and may be multifactorial.[ As with any traumatic and life-threatening experience, electrical injury may result in post traumatic psychiatric disorders. There exist several non-profit research institutes that coordinate rehabilitation strategies for electrical injury survivors by connecting them with clinicians that specialize in diagnosis and treatment of various traumas that arise as a result of electrical injury.
]
Deliberate uses
Medical uses
Electric shock is also used as a medical therapy, under carefully controlled conditions:
* Electroconvulsive therapy
Electroconvulsive therapy (ECT) is a psychiatry, psychiatric treatment where a generalized seizure (without muscular convulsions) is electrically induced to manage refractory mental disorders.Rudorfer, MV, Henry, ME, Sackeim, HA (2003)"Electroco ...
or ECT, a psychiatric therapy for mental disorder
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
s
* As a surgical tool for cutting or coagulation. An electrosurgical unit (ESU) uses high currents (e.g. 10 amperes) at high frequency (e.g. 500 kHz) with various schemes of amplitude modulation to cut or coagulate
* As a treatment for fibrillation or irregular heart rhythms: see Defibrillation
Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''cou ...
and Cardioversion
Cardioversion is a medical procedure by which an abnormally fast heart rate (tachycardia) or other cardiac arrhythmia is converted to a sinus rhythm, normal rhythm using electricity or pharmaceutical drug, drugs. Synchronized electrical cardiover ...
* As a method of pain relief
Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals pr ...
: see Transcutaneous electrical nerve stimulation
Transcutaneous electrical nerve stimulation (TENS or TNS) is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the complete range of transcutaneously applied currents ...
(TENS)
* As a treatment for excessive sweating
Hyperhidrosis is a condition characterized by abnormally increased sweating, in excess of that required for regulation of body temperature. Although primarily a benign physical burden, hyperhidrosis can deteriorate quality of life from a psychologi ...
with a process called iontophoresis
Iontophoresis is a process of transdermal drug delivery by use of a voltage gradient on the skin. Molecules are transported across the stratum corneum by electrophoresis and electroosmosis and the electric field can also increase the permeability ...
* Electrodiagnosis
Electrodiagnosis (EDX) is a method of medical diagnosis that obtains information about diseases by passively recording the electrical activity of body parts (that is, their natural electrophysiology) or by measuring their response to external elect ...
, for example nerve conduction studies
A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests may be performed by medical specia ...
and electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyog ...
* Electroporation
Electroporation, or electropermeabilization, is a microbiology technique in which an electrical field is applied to cells in order to increase the permeability of the cell membrane, allowing chemicals, drugs, electrode arrays or DNA to be introdu ...
for gene delivery
Entertainment
Mild electric shocks are also used for entertainment, especially as a practical joke
A practical joke, or prank, is a mischievous trick played on someone, generally causing the victim to experience embarrassment, perplexity, confusion, or discomfort.Marsh, Moira. 2015. ''Practically Joking''. Logan: Utah State University Press. ...
for example in such devices as a shocking pen or a shocking gum
Shocking gum is a practical joke device that delivers a mild electric shock. The victim is offered what appears to be the last stick of gum from a box, and touching or pulling this triggers the shock. A few novelty companies have produced these ...
. However devices such as a joy buzzer and most other machines in amusement park
An amusement park is a park that features various attractions, such as rides and games, as well as other events for entertainment purposes. A theme park is a type of amusement park that bases its structures and attractions around a central ...
s today only use vibration that feels somewhat like an electric shock to someone not expecting it.
It is also used entertainingly for sex stimulation. This is usually done via the use of an erotic electrostimulator which induces erotic electrostimulation
Erotic electrostimulation (abbreviated erotic e-stim and also known as electrosex) is a sexual practice involving the application of electrical stimulation to the nerves of the body, with particular emphasis on the genitals, using a power source ...
. These devices may include a violet wand, transcutaneous electrical nerve stimulation
Transcutaneous electrical nerve stimulation (TENS or TNS) is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the complete range of transcutaneously applied currents ...
, electrical muscle stimulation
Electrical muscle stimulation (EMS), also known as neuromuscular electrical stimulation (NMES) or electromyostimulation, is the elicitation of muscle contraction using electric impulses. EMS has received an increasing amount of attention in the ...
, and made-for-play units.
Policing and personal defense
Electroshock weapon
An electroshock weapon is a less-lethal weapon that utilizes an electric shock to incapacitate a target by either temporarily disrupting voluntary muscle control and/or through pain compliance. There are several different types of electroshock w ...
s are incapacitant
Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventional ...
weapon
A weapon, arm or armament is any implement or device that can be used to deter, threaten, inflict physical damage, harm, or kill. Weapons are used to increase the efficacy and efficiency of activities such as hunting, crime, law enforcement, s ...
s used for subduing a person by administering electric shock to disrupt superficial muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
functions. One type is a conductive energy device (CED), an electroshock gun popularly known by the brand name "Taser
A taser is an electroshock weapon used to incapacitate people, allowing them to be approached and handled in an unresisting and thus safe manner. It is sold by Axon, formerly TASER International. It fires two small barbed darts intended to ...
", which fires projectiles that administer the shock through a thin, flexible wire. Although they are illegal for personal use in many jurisdictions, Tasers have been marketed to the general public. Other electroshock weapons such as stun guns, stun batons ("cattle prods"), and electroshock belt
An electroshock weapon is a less-lethal weapon that utilizes an electric shock to incapacitate a target by either temporarily disrupting voluntary muscle control and/or through pain compliance. There are several different types of electroshock we ...
s administer an electric shock by direct contact.
Electric fence
An electric fence is a barrier that uses electric shocks to deter people or animals from crossing a boundary. The voltage of the shock may have effects ranging from discomfort to death. Most electric fences are used for agricultural fencing an ...
s are barriers that use electric shocks to deter animals or people from crossing a boundary. The voltage of the shock may have effects ranging from uncomfortable, to painful or even lethal. Most electric fencing is used today for agricultural fencing
In agriculture, fences are used to keep animals in or out of an area. They can be made from a wide variety of materials, depending on terrain, location and animals to be confined. Most agricultural fencing averages about high, and in some places ...
and other forms of animal control purposes, though it is frequently used to enhance security of restricted areas, and there exist places where lethal voltages are used.
Torture
Electric shocks are used as a method of torture
Torture is the deliberate infliction of severe pain or suffering on a person for reasons such as punishment, extracting a confession, interrogation for information, or intimidating third parties. Some definitions are restricted to acts c ...
, since the received voltage and current can be controlled with precision and used to cause pain and fear without always visibly harming the victim's body.
Electrical torture has been used in war and by repressive regimes since the 1930s. The United States Army is known to have used electrical torture during World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. During the Algerian War
The Algerian War, also known as the Algerian Revolution or the Algerian War of Independence,( ar, الثورة الجزائرية '; '' ber, Tagrawla Tadzayrit''; french: Guerre d'Algérie or ') and sometimes in Algeria as the War of 1 November ...
electrical torture was used by French military forces. Amnesty International
Amnesty International (also referred to as Amnesty or AI) is an international non-governmental organization focused on human rights, with its headquarters in the United Kingdom. The organization says it has more than ten million members and sup ...
published a statement that Russian military forces in Chechnya
Chechnya ( rus, Чечня́, Chechnyá, p=tɕɪtɕˈnʲa; ce, Нохчийчоь, Noxçiyçö), officially the Chechen Republic,; ce, Нохчийн Республика, Noxçiyn Respublika is a republic of Russia. It is situated in the ...
tortured local women with electric shocks by attaching wires onto their breasts.
The ''parrilla'' () is a method of torture
Torture is the deliberate infliction of severe pain or suffering on a person for reasons such as punishment, extracting a confession, interrogation for information, or intimidating third parties. Some definitions are restricted to acts c ...
whereby the victim is strapped to a metal frame and subjected to electric shock. It has been used in a number of contexts in South America. The ''parrilla'' was commonly used at Villa Grimaldi
Villa Grimaldi is considered the most important of DINA’s (Dirección de Inteligencia Nacional, the Chilean secret police during the Pinochet regime) many complexes that were used for the interrogation and torture of political prisoners during ...
, a prison complex maintained by Dirección de Inteligencia Nacional
The Dirección de Inteligencia Nacional ( en, National Intelligence Directorate) or DINA was the secret police of Chile during the dictatorship of Augusto Pinochet. The DINA has been referred to as "Pinochet's Gestapo". Established in November ...
, a part of the Pinochet
Augusto José Ramón Pinochet Ugarte (, , , ; 25 November 1915 – 10 December 2006) was a Chilean Captain general#Chile, general who ruled Military dictatorship of Chile (1973–1990), Chile from 1973 to 1990, first as the leader of the Gover ...
regime. In the 1970s, during the Dirty War
The Dirty War ( es, Guerra sucia) is the name used by the military junta or civic-military dictatorship of Argentina ( es, dictadura cívico-militar de Argentina, links=no) for the period of state terrorism in Argentina from 1974 to 1983 a ...
, the parrilla was used in Argentina. Francisco Tenório Júnior (known as Tenorinho), a Brazilian piano player, was subjected to the parrilla during the military dictatorship in Brazil
The military dictatorship in Brazil ( pt, ditadura militar) was established on 1 April 1964, after a coup d'état by the Brazilian Armed Forces, with support from the United States government, against President João Goulart. The Brazilian dicta ...
.
Advocates for the mentally ill
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
and some psychiatrist
A psychiatrist is a physician who specializes in psychiatry, the branch of medicine devoted to the diagnosis, prevention, study, and treatment of mental disorders. Psychiatrists are physicians and evaluate patients to determine whether their sy ...
s such as Thomas Szasz
Thomas Stephen Szasz ( ; hu, Szász Tamás István ; 15 April 1920 – 8 September 2012) was a Hungarian-American academic and psychiatrist. He served for most of his career as professor of psychiatry at the State University of New York Upstate M ...
have asserted that electroconvulsive therapy (ECT) is torture when used without a ''bona fide'' medical benefit against recalcitrant or non-responsive patients.
The Judge Rotenberg Center
The Judge Rotenberg Center (founded in 1971 as the Behavior Research Institute) is an institution in Canton, Massachusetts, United States, for people with developmental disabilities, emotional disorders, and autistic-like behaviors. The center ...
in Canton, has been condemned for torture by the United Nations special rapporteur on torture for its use of electric shocks as punishment as part of its behavior modification
Behavior modification is an early approach that used respondent and operant conditioning to change behavior. Based on methodological behaviorism, overt behavior was modified with consequences, including positive and negative reinforcement continge ...
program.
Japanese serial killer
A serial killer is typically a person who murders three or more persons,A
*
*
*
* with the murders taking place over more than a month and including a significant period of time between them. While most authorities set a threshold of three ...
Futoshi Matsunaga
is a Japanese serial killer who both defrauded and tortured his victims in what is collectively known as the Kitakyūshū Serial Murder Incident ( ja, 北九州連続殺人事件). Matsunaga was convicted of six counts of murder and one count ...
used electric shocks to control his victims.
Capital punishment
Electric shock delivered by an electric chair
An electric chair is a device used to execute an individual by electrocution. When used, the condemned person is strapped to a specially built wooden chair and electrocuted through electrodes fastened on the head and leg. This execution method, ...
is sometimes used as an official means of capital punishment
Capital punishment, also known as the death penalty, is the state-sanctioned practice of deliberately killing a person as a punishment for an actual or supposed crime, usually following an authorized, rule-governed process to conclude that t ...
in the United States, although its use has become rare from the 1990s onward due to the adoption of lethal injection. Although some original proponents of the electric chair considered it to be a more humane execution method than hanging, shooting, poison gassing, etc., it has now generally been replaced by lethal injection
Lethal injection is the practice of injecting one or more drugs into a person (typically a barbiturate, paralytic, and potassium solution) for the express purpose of causing rapid death. The main application for this procedure is capital puni ...
s in states that practice capital punishment. Modern reporting has claimed that it sometimes takes several shocks to be lethal, and that the condemned person may actually catch fire before death.
Other than in parts of the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, only the Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
reportedly has used this method, from 1926 to 1976. It was intermittently replaced by the firing squad
Execution by firing squad, in the past sometimes called fusillading (from the French ''fusil'', rifle), is a method of capital punishment, particularly common in the military and in times of war. Some reasons for its use are that firearms are us ...
, until the death penalty was abolished in that country. Electrocution remains legal in at least 4 states (Florida, Alabama, North Carolina and Kentucky) of the United States.Death Penalty Information Center
See also
*Electrical burn
An electrical burn is a burn that results from electricity passing through the body causing rapid injury. Approximately 1000 deaths per year due to electrical injuries are reported in the United States, with a mortality rate of 3-5%. Electrical bur ...
*Electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
*Graduated electronic decelerator
The graduated electronic decelerator (GED) is an aversive conditioning device that delivers a powerful electric skin shock to punish behaviors considered undesirable. The GED was created by Matthew Israel for use on students at the Judge Roten ...
*Lichtenberg figure
A Lichtenberg figure (German ''Lichtenberg-Figuren''), or Lichtenberg dust figure, is a branching electric discharge that sometimes appears on the surface or in the interior of insulating materials. Lichtenberg figures are often associated wit ...
*Lightning injury
Lightning injuries are injury, injuries caused by a lightning strike. Initial symptoms may include heart asystole and respiratory arrest. While the asystole may resolve spontaneously fairly rapidly, the respiratory arrest is typically more prolon ...
*Milgram experiment
The Milgram experiment(s) on obedience to authority figures were a series of social psychology experiments conducted by Yale University psychologist Stanley Milgram. They measured the willingness of study participants, 40 men in the age range ...
References
Cited sources
*
External links
National Institute for Occupation Safety & Health: Worker Deaths by Electrocution
a CDC
The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency, under the United S ...
study
Effect of Electric Shock Currents on Humans
* ELECTRICAL INJURY AND ITS EFFECT
{{DEFAULTSORT:Electric Shock
Corporal punishments
Electrical safety
Medical emergencies
Torture
Electrical injuries
Causes of death
Occupational safety and health
Effects of external causes