Safety is a part of every job, but it is especially important when working with or around potentially energized electrical equipment.
Each year, approximately 1,000 people die in accidents related to electricity.
More than half of these deaths occurred in cases where the voltage was less than 600 V. Under the right conditions, as little as 50 V can be fatal.
This article briefly examines a few of the approaches that can be taken to minimize the dangers involved in working with electricity.
Never place yourself in a position where you might become part of a circuit. If you are not part of the circuit, the electricity will have to find another path to travel.
(Photo: Be sure to wear proper safety equipment when working with electricity; Credit: Shutterstock)
To avoid becoming part of the circuit, you must follow good work practices and use the available specialized safety equipment.
A variety of safety equipment is designed specifically for use around energized electrical circuits. Some of this equipment includes:
Ground cables: Placing a ground cable on a piece of equipment and connecting it to a ground (e.g., water pipe or indicated ground) creates a path of least resistance through the ground cable and reduces the chance that your body will become a path. Some equipment incorporates grounding connections as part of the installation.
Insulating material: When you are required to work with or near energized electrical equipment, place insulating material between you and energized components. For example, wear special rubber gloves designed to withstand high voltages. Protective sleeves and shoulder protection may also be used.
You can also place rubber matting around or over potentially energized components and on the floor where you will be standing.
Some rubber materials contain carbon, a conductor of electricity. Therefore, use only those rubber materials specifically designed and labeled for use with energized equipment.
It is always important to personally examine protective equipment for damage such as cuts and holes. Flaws will reduce the insulating value of the equipment and place you in danger.
Ground-fault circuit interrupters (GFCI): Electric tools and equipment (for example, drills, grinders, or saws) should be connected to a GFCI. These devices are designed to protect you if a faulty circuit develops in the equipment. In addition, always inspect your tools’ power cords, extension cords, and drop lights for damage, exposed wires, and altered connections.
Low-voltage equipment: When working in wet or hazardous locations, use low-voltage (12 V or 24 V) equipment if possible. Even if a problem develops when using low-voltage equipment, severe injury is unlikely.
2. Use Lockout/Tagout Procedures
The best way to avoid being injured in an electrical accident is to de-energize the circuit. If the circuit is de-energized, there is no voltage source, and the possibility of shock or electrocution is eliminated.
The U.S. Occupational Safety and Health Administration (OSHA) requires a procedure known as lockout/tagout.
This method is used to ensure that once a circuit has been de-energized, it cannot be reenergized without the knowledge and permission of the person who established the lockout/tagout.
Lockout involves placing a lock on the part of the machine that controls energy, thus locking the energy control device in the off position.
Any kind of lock can be used, but the lock should serve no other purpose.
A tag is placed on the device to indicate that it is de-energized. Tags may be attached by hand, but they cannot be reused.
They may be self-locking but must require at least 50 pounds of strength to be released.
Paragraph 3 of the Canadian Electrical Code 2-304 describes the lockout/tagout requirements in Canada.
3. Take Emergency Actions
Damage to equipment and property is secondary when human life is involved.
Therefore, if emergency conditions caused by faulty electrical equipment arise, they must be addressed in the following order: Extinguish any threat to human safety or human life and then address threats to equipment and other materials.
Human involvement: When a person becomes the path of least resistance for an electric current, that person must first be separated from the source of voltage. This is best accomplished by turning off the power to the circuit involved. Opening a circuit breaker or throwing a switch may be all that is required.
However, if the circuit cannot be de-energized within a short time, the person must be removed from contact with the source.
Under no circumstances should you, the rescuer, attempt to touch the person receiving the shock. You too could become part of the circuit.
Instead, use an insulating material such as dry wood or dry rope to push or pull the person away from contact with the energized equipment.
Once the person has been separated from the energy source, first aid measures must be taken.
The first step is to call for help. Use a nearby phone to call 911 or other appropriate emergency contact number. Frequently, the person’s heart stops as a result of the electric shock.
If this happens, properly trained personnel should start CPR immediately. If there is evidence of thermal burns, these will also need to be treated by qualified personnel.
Fire or explosion involvement: When an electrical fault results in a fire or explosion, the first action is to contact the appropriate emergency response personnel. This may involve calling 911 or the local emergency contact point at your plant.
If possible, turn off the power to the equipment involved. Often, simply opening the circuit will cause the fire to go out. If you are trained to do so, you may attempt to put the fire out using an appropriate extinguishing agent.
Electrically energized fires are designated Class C fires, and they require a nonconducting extinguishing agent such as carbon dioxide.
Dry chemical fire extinguishers can also be used on electrical fires. When faced with an electrical fire, you must use only an extinguisher specified for Class C fires.
Keep in mind, though, that once the power to the burning electrical equipment has been shut off, it is no longer a Class C fire and other extinguishing agents may be used.
It is critical to be well educated about the hazards of electricity and the importance of safety when working around electricity.
You can use this knowledge in your home or at work. Make sure you, and those you supervise, always wear proper personal protective equipment and follow safe working practices.
This article is adapted from BOMI International's Electrical Systems and Illumination course, part of the SMA® and SMT® designation programs.