2009 The Basics of Electrical Safety
“Like a tiger cub that has grown up, we tend to be so “used to” electricity that we can easily forget how dangerous it can be.”
Rob Vajko
8/19/2009
www.nationalsafetyinc.com
The Basics of Electrical Safety Do you remember your last power outage? If you’re like most people than it didn’t take you long to realize how dependant you actually are on electricity. Can’t go online, can’t watch TV, can’t put in a movie, house starts getting cold, can’t cook, etc… Electricity is an integral part of our lives and one that we take for granted most of the time. We flip a switch and the light comes on; we don’t think about it, we just flip the switch. And it is this familiarity that can, if we aren’t careful, become dangerous. The truth is that almost 600 people each year get killed by electricity and thousands are injured, some seriously; some in ways that leave them crippled for life. Electrocutions are the fourth most common cause of death in the workplace. Like a tiger cub that has grown up, we tend to be so “used to” electricity that we can easily forget how dangerous it can be. Understanding the nature of electricity and the potential hazards involved is crucial for a safe handling of the power we live with daily. Electrical Safety training isn’t just for electricians.
How many milliamps does it take? One of the most common misconceptions is that lower amounts of power aren’t that dangerous. The truth is that it’s more about the conditions that are present (grounding, path of current, etc…) than about the amount of current. As little as 0.5 milliamps can be detected by the human body and as little as 0.05 milliamps can be fatal. Even appliances and other electrically powered equipment that is no longer connected to a power source can be fatal. Stored electricity that has not been purged can still pose a threat.
Understanding the terms • • • • • •
Conductors – “current-friendly” elements; substances that offer little or no resistance to the flow of current Current – The flow or movement of electrical charge Grounding – A conductive connection to the earth that serves to dissipate the current Insulators – Substances that offer a high resistance to the flow of current Resistance – Anything that impedes or opposes the flow of current Voltage – a measurement of the force of current
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www.nationalsafetyinc.com Electricity and the human body Direct Injuries Direct injuries are injuries that are directly due to contact with electricity. The severity of the injury will depend on three factors: 1. The path that the current takes as it travels through the body. One of the reasons that electricity is so often fatal is that the point of entry and the point of exit usually goes through the heart. The point of entry is usually a hand. The electrical current exits through whichever point of the body is grounded. This is usually the foot which is in contact with the ground or some other point of contact or the other hand which is touching something else. The heart is right in the middle of both of these paths. 2. The amount of current that travels through the body 3. The amount of time that the current is in the body. The longer the currant is in the body the more damage it inflicts. The soft tissues in the body, partly because of the high water content, are the most affected. This means that the greatest damage is done to vital organs like the heart, the liver, etc… As little as 3 milliamps will result in shock. By 10 milliamps or so the body will start having muscular contractions. By 30 milliamps the person will start experiencing respiratory paralysis, by 50 heart paralysis. Anything over this has a high chance of being fatal. At 75 milliamps the heart can go into fibrillation which brings about death unless a defibrillator is used in time. Tissue burning and scalding is also present above 4-5 amps. A simple Google image search under “Electrical Burns” will turn up enough photos to drive home the severity of this form of injury (Not a recommended search for those with weak stomachs) Additionally, because the softer tissue is beneath the skin (dry skin is a very poor conductor. Moisture in the skin, however, rapidly increases the conductivity) many of these burns happen under the skin and aren’t visible until imaging and other medical techniques are used. Indirect Injuries In addition to the direct injuries we have what we are calling “indirect injuries”. Indirect injuries are injuries that are caused by trauma as a result spasms or falls causes by an electrical jolt. Because electricity causes muscles spasms and because people react to electrical shock, many of the injuries are not a direct result of the electrical current but rather because of a fall or blow due to the reaction to the shock.
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www.nationalsafetyinc.com Falls are the most common of these. A worker who gets an electric shock falls and injures himself or kills himself as a result of the fall. Other reactions to the shock can cause a worker to injury himself by slamming into an object, dropping equipments or tools. In this category of indirect injuries we also need to list fires. Electrical shorts cause over 2,000 deaths each year as well as billions of dollars of property damage. Especially susceptible are older homes with old and faulty wiring. Arc Flash Injuries Arc Flash is a complete course in itself. Check out the arc flash section on our website at www.nationalsafetyinc.com for a complete “The Basics of Arc Flash Protection” document as well as other downloads and related articles.
Protecting against the hazards of electricity The old adage that the problem with common sense is that it is common enough holds true here. Most electrical injuries and fatalities could have been avoided with a little common sense and prevention.
Tips for working safely around electricity: •
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Make sure that GFCIs (Ground Fault Circuit Interrupters) are installed in wall receptacles, circuit breakers and portable plug-ins. There is no single thing that you can do to decrease the chance of electrical injury in and around the house than this. Fire officials have estimated that some 30,000 homes fires a year could be prevented by simply using GFCIs. Use extension cords with built-in GFCI or that is plugged into a GFCI (Coleman Cable has a great one. See it here) Always turn off the power before moving or working on any electrical apparatus or machine. In industrial settings, be sure to read and apply safety procedures associated with lockout/tagout (you can download “The Basics of Lockout/Tagout” from our website at www.nationalsafetyinc.com under the lockout/tagout section) Pay attention to the quality of the electrical and electronic equipment that you purchase. Although compliance agencies require testing and certification, there is an increase in counterfeits that may bear all the seals of approval and certification but that are actually forgeries that have been built with inferior parts and products. (For more information on electrical counterfeits go to: http://esfi.org/node/565) Avoid working with electricity around water and wet conditions. Never work on live circuit panels. The danger of arc flash is simply too great. Call a professional. Educate yourself on the proper use and hazards of improper use for all electrical equipment that you use (power tools, space heaters, power generators, extension cords, etc…). Educate yourself and your children on any and home electrical safety issues.
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www.nationalsafetyinc.com If the worse should happen… • • • • • • •
Do not touch a person who is being electrocuted, the odds are that you will become another victim rather than save the person. To free the person who is being electrocuted look first for the source of source of power and turn if off. If you cannot access the source of the power, use a non-conductive material to remove them from the electrical current (dry wood, cardboard or plastic) Immediately call 911. Even if the person appears okay, there might be internal, non-visible injuries. Lay the person down and elevate their legs. Begin CPR if the patient is no longer breathing. Treat any burns while waiting for help to arrive. For electrical fires, make sure that you use the appropriate fire extinguishers. Water only increases the risk of electrocution.
Additional Resources: -
http://www.osha.gov/SLTC/electrical/index.html - The OSHA site with a ton of information on all things related to electrical safety. http://esfi.org – The home of the Electrical Safety Foundation International. http://www.elec-toolbox.com/Safety/safety.htm - The Electrician’s Toolbox Etc… website
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