It’s a sad truth that electrical accidents happen — and that they happen with frequency. For the 20 years spanning 1992 and 2013, the U.S. Bureau of Labor Statistics (BLS) reports that there were almost 6,000 on-the-job electrical injuries that resulted in death. Moreover, in the 10 years between 2003 and 2012, there were 24,100 non-fatal electrical injuries. These numbers show that electrical safety has to be constant priority for every professional electrician.
Fortunately, the trend in fatality data is going down. In 2013, there were 139 fatalities from electrical injuries. That’s down from 334 fatalities in 1992. The data for non-fatal injuries, however, show no clear trend.
It’s critical that professional electricians have the requisite knowledge and understand the procedures required to perform their job safely. It’s also important to take ongoing electrical safety training. Read on to learn about the common risks associated with electrical work. You’ll also learn how you can prevent on-the-job accidents and injury.
The Most Common Risks
One of the biggest risks that professional electricians face comes from overhead powerlines. The BLS reports that over 40% of all fatal electrical injuries from 2003 to 2010 were due to coming in contact with overhead powerlines. It’s common knowledge that such contact should be avoided, and yet this remains a significant safety issue.
Non-fatal injuries can be significant, too. The majority of these non-fatal injuries involved coming in contact with live electric current in machinery or wiring, transformers, or other components. In many cases, the work that was being done when the injury occurred was being performed in an inappropriate way. This highlights the need for proper training and continual refreshers to increase safety when working with and around electrical equipment.
Don’t Take Shortcuts
The Occupational Safety and Health Administration (OSHA) has investigated many of these injury-related accidents. OSHA has learned that some of the accidents came when electricians weren’t aware of live electrical sources. This indicates that the electrician was not fully prepared to perform the work. Being fully prepared means performing a thorough pre-job assessment that identifies every potential electrical source and hazard.
Sometimes that sort of pre-job assessment doesn’t get the attention that it should. Time pressures to complete a task or a demanding supervisor can contribute to the danger. They can also lead to unqualified people working in places they shouldn’t and taking shortcuts on safety equipment. The Fire Protection Research Foundation suggests that significant efforts need to be made to educate workers about these dangers and ensure they are minimized.
Understanding How to Avoid Injuries
Proper training is crucial in understanding how to avoid injuries. It takes training and practice to have the confidence to know not to rush on a project, despite outside pressures. It takes knowledge to know what to do and also appreciate when you are unprepared for a particular situation. If you’re not completely sure, you need to ask. While you may not want to convey a lack of knowledge, it is far better than sustaining a serious injury.
Everyone working with electrical systems should be able to identify electrical hazards associated with:
- Electric shocks/burns, arcs, and blasts.
- Fault current and potential difference.
- Electrical safety in industrial plants.
As a professional electrician, you should also know the characteristics of arc flash and arc blast hazards.
With regard to electric burns, most people don’t appreciate the fact it only takes a few seconds of exposure to a heat source to cause a burn. Water heated to 140 degrees Fahrenheit causes a third degree burn in five seconds. Live electrical systems can be much hotter than that.
The Workplace Safety Awareness Council also stresses how only a short exposure time can lead to serious injury. Exposure to 203 degrees Fahrenheit for only 1/10th of a second can cause a third-degree burn. Think about that for a moment. Most alternating current (AC) runs at 60 cycles per second (60 Hz). In 1/10th of a second, that’s just six cycles, but it’s still enough to cause a third-degree burn. It only takes less than a second to have a mistake result in a costly injury.
In The Home: Power Receptacles and Cords
When performing electrical work in a home, you can come across several different potential risk areas. Before you begin working, it is key to take your time inspecting the home in order to identify and address potential risks.
When working in a home, one common danger comes from power receptacles that don’t have a ground-fault circuit-interrupter. They’re supposed to have this protection, but sometimes they don’t. You have to double check in each case to ensure your safety and the safety of others.
You also need to ensure that in any completed installation, every receptacle — or outlet box — needs to have a cover. If that cover is metal, then it has to be grounded.
Another common problem is improper substitutions. Often, you’ll find flexible power cords being used as a substitute for wiring of a structure. Power cords aren’t intended to provide structural stability. When used in this inappropriate way, they can fray, break, and expose a live wire. Exposed wires cannot be “taped up” with electric tape to make them okay — that’s not acceptable, and it imposes safety risks.
You also have to watch for power cords that are run through walls, ceilings, floors, or across doorways and windows. You can’t see a cord that’s hidden, which presents a significant challenge for you. You still are responsible for ensuring you know where every cord that you could possibly encounter is. You also need to ensure it is installed safely and doesn’t present a threat to you or anyone working with you.
Power cords that span doorways or windows present obvious hazards. In a doorway, someone could trip over the wire, causing a direct injury. That tug on the cord could also cause damage to the electrical socket or other electrical device. Power cords in windows can be damaged by opening and closing the window, and they can also be damaged by exposure to the elements. This in turn can cause a fire hazard.
When you are working with extension cords, you have to look for any tears in the insulation, a pinched cord, or a missing ground pin. If you find any of these, discard that extension cord and use a new one. Also, use the rule that you should test all grounding conductors at least every three months. That way, you’ll have less chance to use a damaged grounding conductor.
Portable Tools and Circuit Breakers
Not only do you need to be well aware of your job location, you also need to be careful with the tools you are using. Portable tools are the stock and trade of every electrician. But even a tool that is itself safe can be rendered unsafe when used incorrectly.
For example, plugging a tool into an extension cord with a wire that’s too small for the tool is very dangerous. The tool will draw more current than it would with the appropriately sized wire. The extra current could cause the tool to overheat and burst into flames.
You might expect a circuit breaker on the circuit to trip before the tool overheats. In this case, however, the circuit breaker might not trip because it is not designed for use with this size wire. The use of the smaller wire might not trip the breaker, setting you up for a burn injury or much worse.
Speaking of circuit breakers, before you start your job, review the circuit breakers and ensure that every breaker is labeled clearly to indicate what its purpose is. If it’s unlabelled or illegible, then you need to research that breaker until you are confident it is either not relevant to your project or you understand how it is relevant.
Arc flashes are another common danger that professional electricians face. They can happen anywhere, making them a common potential risk.
An arc flash can occur when there’s an electrical fault — or short-circuit — with a low impedance connection in an electrical system. The size of an arc flash depends on many factors, such as:
- Closure time
- The size of the arc gap
Regardless of their size, arc flashes release four different threats:
- Thermal energy
- Acoustic energy
- A pressure wave
Let’s look at the last three of these first.
The sound of an arc flash can reach 160 decibels (dB), about as loud as pistol being fired or a jet engine at a distance of 100 feet. The pressure wave can be very forceful: At two feet, a person can feel a force of 500 pounds. This force can rupture eardrums, and it can blow debris that could also cause injuries.
As considerable as these risks are, the thermal energy in an arc flash is a very significant threat to you and anyone around you. Temperatures in an arc flash can reach 35,000 degrees Fahrenheit. By comparison, the surface of the sun is about 10,000 degrees Fahrenheit. Since third-degree burns can occur in 1/10th of a second at about 200 degrees Fahrenheit, it should be no surprise that an arc flash can be a real threat, and not just to you, but over a wider area around you.
The Workplace Safety Awareness Council points out that arc flashes are potentially fatal even at a distance of more than 10 feet from the arc gap. Each year, there are more than 30,000 arcs, which result in over 7,000 burn injuries. These burn injuries, even if non-fatal, cause tremendous damage and result in long hospital stays. The average hospitalization is 19 days with total hospital costs between $200,000 and $750,000.
There’s an easy way to avoid arc flashes — de-energize the equipment you are working on. That sounds simple, and it is simple. Yet still, there are more 80 arcs every day.
When you de-energize a circuit, you have to “lock it out” and tag it. Special locks are available that provide a clear statement to anyone not to operate the circuit. The lock will prevent the circuit from activating unless someone breaks the lock.
We can imagine times when it may be impractical to lock out a system. For example, if the system is providing life support to a patient, that system cannot be locked out. Similarly, emergency alarms, equipment that is venting hazardous materials, and other similar scenarios have different requirements. OSHA allows working on live systems in these cases. Of course, you must use extra care in those circumstances.
The Boundary Approach
Since the danger of an arc flash decreases with the distance from the flash, a circular boundary approach can be an effective strategy for providing layers of safety in the region. It works by designating potential risk areas and avoiding them.
From the source of a potential arc flash, there is a first circular boundary of “prohibited approach.” No one should be located in this area. Next comes a boundary of “restricted approach.” People should approach and enter this area only if necessary. If they must enter this second boundary, they need to do so with caution. Beyond that is a boundary of “limited approach,” which offers flash protection. In this case, flash protection is defined as being in a zone where the greatest degree of burn that someone would experience is second degree. Boundaries can be computed using established standards, such as IEEE Standard 1584.
Any time there is a known arc flash hazard, a label must be posted that declares the hazard, the approach boundaries, and personal protective equipment (PPE) that is required to operate in the area. PPE often includes face shields, safety glasses, hard hats, special shoes, insulating gloves, and flame resistant clothing. Boundaries can be computed using established standards, such as IEEE Standard 1584, which are available in software products or in available spreadsheets.
Ongoing Electrical Safety Training
Only qualified professionals should perform electrical work. That means you have to be able to identify live electrical components from other de-energized components. You also have to be able to determine the voltage on exposed live components. In addition, you have to understand the clearance distances and the voltages that you’ll be exposed to.
Becoming a certified electrician, however, should not be the end of your education. As technology evolves, there are new risks and new ways to prevent injuries. Taking advantage of ongoing electrical safety training not only can expose you to new developments in the industry, it can also provide a life-saving refresher on safety tips.
We offer technical skills development services through our continuing electrical safety training classes. These classes are designed for professional electricians who want to keep up-to-date on procedures. For more information, call us toll free at (866) 316-5580 or email firstname.lastname@example.org. By taking continuing electrical safety training classes, you can ensure your knowledge of electrical safety enforcement is current with all OSHA and National Fire Protection Association (NFPA) requirements.