Electrical Hazards

No matter what your trade, on many jobs you will use or work around electrical equipment. Extension cords, power tools, and portable lights are among the many pieces of equipment that use electricity.

There are different types of electrical accidents, including:

Burns.
Electric shock.
Explosions.
Falls caused by electric shock.
Fires.

Burns caused by electric shock are a result of the heat caused by resistance to electrical current. Electrical burns often occur below the skin surface and can damage muscle and nerve tissue. In severe cases, electrical burns can be fatal. The extent of injury due to electric shock depends on a combination of voltage and current, and the body's resistance to the electricity passing through it—a condition that changes from person to person. An electric shock occurs when you become part of the electrical circuit; when you contact a live portion of a circuit while in also in contact with a lower potential such as ground. Even though you may normally deal with small voltages and current, the values are never far away from lethal levels. You can receive a shock or burn from any common electrical circuit.

The severity of the electrical shock depends on a number of factors:

1. The amount of current that passes through the body.
2. The path that the current takes through the body.
3. Type of voltage—AC or DC.
4. Voltage strength.
5. The length of time that the current flows within the body.
6. Condition of the skin and the body's chemical makeup.
7. Area of contact.

Normal household current (plugs and light circuits) is generally limited by a circuit breaker to a value of 15 amperes. This device has been designed to trip and open a circuit if the 15 ampere value is exceeded and is designed to protect from property damage. It is possible to cause a fatal injury with a current flow of only 50 milliamperes (mA) or 5 one-hundredths of an ampere. The body is sensitive to relatively small values of current. In comparison, a 100 watt light bulb draws approximately 0.85 amperes (850 mA) of current when connected to a 120 volt source. Remember, we have 15 amperes available in each standard house circuit. Industrial circuits may have a required flow of several hundred amperes. In both cases, these are dangerous amounts!

Most fatal shocks occur when current passes through or near the heart. This is possible if the circuit passes from one arm to the other, from the right arm to the left leg or from the left arm to the right leg. Figure 7 shows the effects of increasing amounts of current on the human body.

Amount of Current	Effect
1 mA or less	No noticeable feeling experienced
1–3 mA	Shock is just felt.
3–10 mA	Shock is painful. Individual can still use motor functions. Muscular control is not lost.
10–20 mA	Some individuals will experience a loss of voluntary muscular control.
20–50 mA	Individual cannot let go of the circuit. Breathing may become difficult.
50–200 mA	Ventricular fibrillation of the heart may occur, causing death. Severe muscular contraction and nerve damage are possible.
Over 200 mA	Heart paralysis may occur. Severe burns are possible

Rescuing shock victims: first aid for electrical shock victims

Consult your employer's first aid attendant or medical personnel on acceptable procedures for dealing with local electrical shock emergencies.

The most important things to know about assisting an electrical shock victim are listed below:

Do not touch a victim who is still connected to the power source. If you touch a victim who is in contact with an electrical source, you will become part of the circuit too, resulting in another casualty.
Safely remove the power from the victim
If you cannot de-energize the circuit, separate the victim from the live circuit by using a piece of nonconductive material such as a stick of lumber or wooden handle.
If the shock victim is unconscious and has stopped breathing, start artificial respiration at once. Do not stop until a medical authority instructs you to stop.

Self Quiz.

1. Long answer. What do you do if a co-worker receives an electric shock?

Do not touch a victim who is still connected to the power source. De-energize the circuit by separating the victim from the live circuit by using a piece of nonconductive materials, such as a stick of lumber or wooden handle. Call first aid or medical emergency.

If the shock victim is unconscious and has stopped breathing, start artificial respiration at once. Do not stop until a medical authority instructs you to stop.

2. Long answer. Please list five factors that contribute to the severity of an electric shock.

Answer.