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Electrical Safety

Information about Electrical Safety

We Have to Know about the Electrical Safety

  • Electric shock is an injury caused by an electrical current passing through the body. The electricity may be atmospheric (lightning) or man-made (high-voltage transmission and low-voltage lines)
  • Possible injuries include burns and physiological disturbances, which may range from a minor burn to death in severe cases.
  • The outcome depends on the severity of the incident
  • Progressive damage is usually much more severe than the original lesion would indicate since the underlying tissues are damaged along the path of the electric shock through the body
  • Extensive burns require long-term hospitalization and often plastic surgery

First Aid

  • Electric current passing through the body can cause breathing to stop or the heart to stop breathing. The longer the person is in contact with the current, the less likely are the chances of survival. The source could be a defective household appliance, electrical wire or lightning. Internal body damage is not always obvious. Always seek medical help immediately

Home treatment

  • Do not approach the person who has been electrocuted until you are certain the area is safe. First, break contact between the person and the current source. Best is to shut off the current at the main fuse box. Do not use the switch of the appliance. If this is not possible, use a wooden stick to separate the person from the appliance. Stand on a rubber mat or stack of newspapers or another non-conducting material
  • A victim who has been struck by lightning poses no more danger to the rescuer
  • Check the ABC’s: airway, breathing, circulation and start CPR if necessary. Check for shock
    • Call 108 for an ambulance
    • With high voltages, the person may have been thrown into the air and may have sustained back head or neck injuries. Handle with care
    • Cover any burnt area with a sterile gauze bandage or a clean cloth. Electrical burns are always worse than they seem. Get to a doctor

Causes of Electrical Safety

Factors that determine the form and severity of injury include:

  • the type and magnitude of the current
  • the resistance of the body at the point of contact – different tissues in the body will offer different electrical resistance
  • the current pathway through the body and the
  • duration of current flow.

AC, particularly of the common 50-60 Hz (cycles/second) variety, is three to five times more dangerous than DC (direct current) of the same voltage and amperage (current strength)

DC tends to cause a convulsive contraction of the muscles, often forcing the victim away from further current exposure.

  • The effects of AC on the body depend to a great extent on the frequency: low-frequency currents (50 – 60 Hz) are usually more dangerous than high-frequency currents. AC causes muscle spasm, often ‘freezing’ the hand (the most common part of the body to make contact) to the circuit. The fist clenches around the current source resulting in prolonged exposure with severe burns. Burns from electricity is the result of extremely high temperatures (up to 5000 degrees C) generated at the point of skin contact with the conductor. They usually involve the skin and the tissues beneath and may be of almost any size and depth. Generally the higher the voltage and the amperage, the greater the damage from either type of current

Do’s and Don’ts of Electrical Safety

  • Never go near or touch power lines. Assume every wire is “live” and never assume a line is “dead.”
  • Do not fly kites, balloons or model airplanes near power lines
  • Before you move a metal ladder, check to see that it’s clear of power lines. They can be deadly if contact occurs with a line
  • Never climb trees, poles, or steel towers whose upper branches are contacting, or even near power lines
  • Never use water on electrical fires
  • Never repair a break in an outdoor extension cord
  • Don’t use indoor lights for outdoor purposes
  • Don’t touch appliances, cords or plugs with wet hands or while standing on a wet surface
  • If you encounter an electrical-injured victim, do not touch the person until they have been freed from the source of electricity
  • Never raise any tall object near a power line
  • Never attempt to open or tamper with transformers
  • If an appliance works improperly or gives the slightest warning of a problem, such as shocks or sparks, disconnect it and have it serviced
  • Take extra precautions when using power tools
  • Prevention of electrical injuries entails proper design, installation, and maintenance of all electrical devices. Education and compliance with instructions as to the use of electric appliances, as well as common sense and respect in dealing with electricity are essential. Any electrical device that touches or may be touched by the body and has life-threatening potential should be properly earthed and incorporated in circuits containing fail-safe equipment. Ground-fault circuit breakers, which trip at current leakage to ground levels of as low as 5mA, are excellent safety devices and are readily available.

Signs & Symptoms of Electrical Safety

In general, the amount of injury to the body is directly proportional to the duration of exposure. This is because tissue breakdown occurs with longer exposure, which allows internal current flow.

Heat is produced by current flow through tissues, causing:

  • Severe burns
  • Protein coagulation – the proteins in the cells clump together, destroying the function of the cells
  • Vascular thrombosis – clotting of blood
  • Tissue necrosis (tissue death)

Physiological changes include:

  • Involuntary muscular contractions and seizures
  • Ventricular fibrillation – a severely disordered rhythm of the heart which is fatal if not corrected
  • Respiratory arrest due to central nervous system injury or muscle paralysis
  • Decreased blood clotting
  • Dehydration
  • Skeletal fractures

The effects and clinical signs and symptoms of electrical injuries depend on a complex interaction of the factors discussed above, and may include the following:

  • An electric shock can startle you and cause you to fall down or be thrown down
  • It may cause severe, rigid contractions of the muscles which in turn may result in fractures, dislocations, and loss of consciousness
  • The respiratory system may be paralyzed and the heart may beat irregularly or even stop beating altogether
  • Sharply demarcated electrical burns may be present on the skin and extend into deeper tissue
  • High voltage may cause the death of tissues between the entry and exit point of the current. Massive swelling of the tissues (edema) may follow as the blood in the veins coagulates and the muscles swell
  • Low blood pressure (hypotension), fluid and electrolyte disturbances and the release of myoglobin (an iron-containing protein present in the muscles) into the circulation can cause kidney failure
  • Bathtub accident victims, who suffer electric shock while in the water, may show no burns but suffer cardiac arrest
  • Lightning rarely leaves entry or exit wounds and seldom causes muscle damage or the release of myoglobin. Coma or other evidence of damage to the nervous system may occur but usually resolves within hours or days. Death is usually due to failure of both the respiratory and cardiac systems

The damage electricity does to the body is determined by the following:

  • The type and magnitude of the current
  • The resistance of the body at the point of contact
  • The pathway of the current
  • The duration of the current flow

The type and magnitude of the current have a profound influence on the injury that is caused by an electrical shock. Direct current (DC) doesn’t cycle (i.e. it doesn’t change between positive and negative) and isn’t as dangerous as alternating current (AC)

DC tends to cause the muscles to contract and this often makes one pull away from the source. AC often causes muscle tetany and “freezes” the hand to the source, thereby increasing the time exposed to the electricity. The “let-go” current is the highest amperage at which you will still be able to pull your hand away when you receive a shock.

For DC this is about 75 milliamperes (mA) and for AC it’s about 15 mA depending on the person’s muscle mass (the higher the muscle mass, the higher the cut-off amperage).

Altered function

  • Generally speaking, the higher the voltage and the amperage, the more dangerous the current. This is true for both DC and AC and they both alter physiological function and cause physical damage
  • Altered physiological function includes involuntary muscle contractions, seizures, ventricular fibrillation (the heart beats so fast that it doesn’t pump any blood), denaturation of proteins, blood clotting problems, dehydration, and cardiac and respiratory arrest
  • Physical damage includes burn wounds, tissue necrosis, fractures, and torn muscles and tendons. The body resistance is measured in ohms/cm2 and is basically determined by the thickness of the skin. Thick calloused skin like the soles may have a resistance as high as 2-3 million ohms/cm2, normal skin’s resistance is typically 20-30 thousand ohms/cm2 and wet thin skin 500 ohms/cm2
  • If the skin is punctured (e.g. cuts, needles) or the current is applied to a mucous membrane (e.g. mouth, rectum, vagina), the resistance may be as low as 200-300 ohms/cm2. If the resistance is high, large surface damage may occur with little deeper damage. It the resistance is low, the person may suffer little if any skin damage, but may still die from cardiac arrest if the current reaches the heart
  • When a radio falls into a bathtub, a person will die of cardiac arrest without suffering any burn wounds. Simplified, the higher the resistance, the more heat is generated in the skin and the lower the chance of deep damage and vice versa

Pathway through the body

  • The pathway of the current through the body is crucial in determining the injury. If the current passes through the heart (head/hand/foot to hand/foot) it may be fatal. 220v at 60Hz AC traveling through the chest for a fraction of a second may induce ventricular fibrillation at currents as low as 60-100mA (300-500mA if DC)
  • If the current has a direct pathway to the heart like in the case of a pacemaker, less than 1mA is needed (AC or DC). The most common entry point for electricity is the hand, followed by the head. The most common exit is the foot. The duration of the current flow, just like the duration of the exposure, is directly proportional to the amount of injury to the body (the heart being the exception as small currents at low voltages may be fatal)
  • The longer the exposure, the more heat is generated and the deeper the electricity penetrates the body. Lighting is a good example because, in spite of the high voltage, very little burn wounds are caused because of the very short duration of flow

Medical advice for Electrical Safety

  • In any case of an electrical accident where burns or loss of consciousness occur you should seek medical attention as soon as possible

Risk factors of Electrical Safety

  • Anyone who is either ignorant of the potential dangers of electricity or who don’t respect these are at risk

Treatment for Electrical Safety

Immediate treatment consists of:

  • separating the victim from the current source,
  • re-establishing vital functions and
  • providing supportive care as required
  • Breaking contact between the victim and the current source can be done either by shutting off the current or by removing the person from contact with it. Shutting off the current source, if this can be done rapidly, is the best method (e.g. throwing a circuit breaker or switch). Disconnecting the device from its electrical outlet or cutting the wires using insulated tools are other methods
  • For low voltage, the rescuer should use an insulating material (cloth, dry wood, rubber, leather belt) to pull the victim free
  • Once it has been established that it is safe to touch the victim, a rapid examination for vital functions (pulse, breathing, and level of consciousness) should be performed. If spontaneous breathing is not observed, or cardiac arrest has occurred, immediate cardiopulmonary resuscitation (CPR) is required. The victim should also be treated for shock and taken to hospital for further treatment
  • A tetanus injection is required for any burn. An ECG, cardiac enzymes, full blood count and urinalysis are baseline investigations required for all electrical injuries. Other tests may be indicated when necessary
  • Any suggestion of damage to the heart, abnormal rhythms or chest pain requires monitoring for at least 24 hours
  • Any deterioration in the level of consciousness requires a CT scan to rule out bleeding into the brain
Electrical Safety
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