Types of electrical injuries

Electrical injury is a term for all injuries caused by contact with electrical energy. Electrical contact can cause a wide variety of injuries involving most organ systems. Most electrical injuries are classified as one of the following:

1. Burns
2. Electric shock injuries
3. Eye injuries

A worker with an electrical injury may have a number of signs and symptoms.

As well as these injuries directly related to the electrical accident, a worker could be thrown or fall if working at a height. As a result, the worker may also have fractures, spinal injuries, or internal injuries.

Burns

Burns are the most common electrical injury. An injured worker may have one or more types of burns:

• Flash burns are caused by heat released when an arc is formed between the electrical source and a ground or between two electrical conductors. In this case, the arc does not pass through the However, electric arcs can produce intense heat (several thousand degrees) — more than enough to melt steel. This heat can cause first- degree through third-degree burns to any part of the worker exposed to the heat. Electric arcs can also generate intense ultraviolet radiation and cause serious eye injury, even at a distance.
• Arcing burns occur when electrical current jumps from the current source to the worker or from one part of a body surface to
• Flame burns caused by the ignition of clothing are common, particularly with high-voltage
• Contact burns occur when skin touches hot surfaces of overheated electrical conductors or other
• Electrical burns are the result of electrical current flowing through tissues or The burn is often only visible at entrance and exit wounds, with the major damage inside the body. Extensive damage to nerves, blood vessels, muscles, and organs may take place as the current passes through the body and generates intense heat (up to 3,000°C).

Electric shock

Electric shock is caused by electric current passing through the body. Electric shock symptoms can range from a barely perceptible tingle to immediate heart stoppage. In addition to the electrical burn injuries discussed on page 50, there may be internal bleeding, unconsciousness, respiratory paralysis, and cardiac disorders.

Electrical current can cause involuntary muscle contractions. These may prevent an injured worker from letting go of the live conductor. Sometimes involuntary movements lead to bruises or bone fractures — or even death from collisions or falls.

In some cases, electric shock can cause injuries that are not evident and symptoms may be delayed. For this reason, all electric shock victims should be taken to hospital for observation.

The damage that electricity does to the body is determined by three major factors:

1. The rate of current flow (measured in amperes, and determined by voltage and resistance)
2. The path of the current through the body
3. The length of time the current is flowing through the body

Other factors that may affect severity of injuries from electric shock are:

4. The frequency of current (for example, 60 cycles)
5. The type of current (AC or DC)
6. The phase of the heart cycle when the shock occurs
7. The general health of the person receiving the shock

It is not possible to say exactly what injuries will occur from any given amperage. The table on page 52 shows the general relationship between the degree of injury and the amount of current flowing through a person in a hand-to-foot path for just a few seconds. Current that

is strong enough to run a 5- or 10-watt light bulb can kill you. Low voltages can be extremely dangerous.

As shown on page 52, a difference of less than 50 mA (milliamperes) exists between a current that is barely perceptible and one that can kill. The degree of injury is proportional to the length of time the body is in the electrical circuit. The longer you’re exposed to the current, the more serious the shock. Low voltage does not mean low hazard.

A 100-watt light bulb uses 1000 mA of current. It takes only 5 mA to trip a ground fault circuit interrupter (GFCI). A small amount of current running through the body for a few seconds can give the effects shown in the table

Eye injuries

Like any other part of your body, your eyes can be burned. Regular safety glasses may not protect against flash burns from electric arcs. Direct or reflected light from an electric arc may cause a surface burn to the cornea. Although flash burns are very uncomfortable, most of those caused by shorter flashes are not serious and usually heal in 12 to 24 hours. With longer flashes of a couple of seconds, permanent retinal damage may occur from the ultraviolet light.

If there is a fire, the eyelids are frequently burned. The treatment of burned eyelids requires specialized medical care. The eyes should not be examined as this may injure the burned tissue. Both eyes should be covered with sterile dressings.

First aid

Electric shock and electrical burns are serious injuries and should receive immediate medical attention. Contact your first aid attendant, if available, or get other medical help. Arrange for transport to hospital immediately.

Make sure you keep yourself and the injured worker out of further danger:

• With low voltage, carefully remove the source of contact from the injured worker without endangering yourself. Turn off the power or use insulated material to remove the source of contact (low-voltage only).
• With high voltage, stay back at least 10 m (33 ) until the owner of the power system says it is safe to approach. Don’t become a second victim. If the voltage is over 60 kV (60,000 V), you may need to keep as far away as 32 m (105 ft.). See page 31 for more information on rescue work around power lines.

First aid for electrical injuries includes the following:

1. Remove the worker from the heat and put out the fire on any clothing by smothering the flames with a blanket or dousing the worker with Make sure that fabric is no longer smouldering. Cooling more than 20% of the body at one time can cause hypothermia. Wet dressings and any clean source of water may be used for cooling. Never apply ice.
2. Initiate priority action following the ABC approach:
   • Airway — Establish and maintain an open
   • Breathing — Check and maintain breathing. If the injured worker is not breathing, start assisted ventilation, using mouth-to-mouth or a pocket
   • Circulation — Monitor the worker’s circulation Start cardiopulmonary resuscitation (CPR) if necessary, and carry on until more advanced life support is obtained. Electrical workers should be familiar with CPR.
3. Keep the injured worker warm and at
4. If the injured worker is conscious, offer
5. If the injured worker vomits, turn the worker onto one side to keep the airway
6. Transport the injured worker to medical aid. While waiting for transport or en route to medical aid, administer first aid for
7. Don’t leave injured workers unattended. Maintain a constant watch on their airway, breathing, and circulation while they are transported to medical