How do you get electrical shocks?
This article elaborates on the dangers of electricity and electrical shock hazards. This is Part 1 of a three-part series. Part 2 will explain on the various levels of injuries the shocks can cause. While Part 3 discusses on the protection against electric shock.
A. The dangers of electricity
Electricity has become such an integral part of our lives that we tend to take it for granted. It has become so familiar that many of us have forgotten about the hazards and the dangers that come with it.
Whenever you use electrical appliances and equipment whether at home or at work, there is always a risk of hazards, especially of getting electric shock. The refrigerator, the washing machines, the space heaters or even electric toys and entertainment equipment; they are all electrical hazards to users and household members at some point in appliances’ life cycles.
Eventually these harmless machines and toys will become liabilities and accidents waiting to happen. You need to watch out for them.
Of course, workers face a much higher risk of injuries and electrocution and this not only apply to workers who use electric tools. Haphazard site work conditions usually have temporary electricity supply cables and extension cords running all over the place on the work floors. All these situations present very high risks of accidents to all workers regardless of their trades and disciplines.
Workers who work on live equipment and wiring installations may find the second part of this article too familiar and therefore an unnecessary reminder for them. However, confidence will not help them avoid electric shocks. It is the respect that can help reduce the chance of accidents from happening. As always accidents usually happen when we least expect it. Ever heard of a zoo tiger killing its own master?
So keep up your vigilance and do not take shortcuts when safety procedures at work are concerned. All safety procedures are here for a reason even if sometimes we are all very reluctant to follow or even to accept some parts of them.
Lastly, let us not forget about the creative do-it-yourselfers. From statistics released by many organizations, many house electrical fires have been a result of imperfect wiring jobs carried out by the not-so-skilled DIY hobbyists. You can bet electric shocks and electrocutions are part of the lists.
A person gets an electric shock when a current passes through the body. This happens when he comes into contact with live metal or live conductors, which will cause the current to flow through our body.
A human body is not supposed to receive this sort of current. Therefore, it is a shock and the body will suffer injuries. These injuries can be serious and can even be fatal.
How the house wiring works
House wiring system in this country normally has three wires with one of them usually green color. The other two black may be black.
Another possible combination may be one black and the other red, yellow, or blue.
The green wires are connected to the earth through steel ground rods half an inch in diameter driven a few feet into the ground. The same ground wires at electrical substation or at power plants (i.e. diesel electric generators) are also connected to the earth mass the same way.
So the house green earth wire and the electrical plant’s earth wires are actually connected to each other via the earth mass. (Remember that earth mass contain water and minerals. Therefore, it is a good conductor of electricity, just like the electrolyte water inside the car battery).
So these green wires are at 0 volts.
One of the other two black wires, or the colored wires, in the house is at 240 volts and it is normally called the LIVE wire.
The last wire is the return path (also called the NEUTRAL wire) for the electrical current in normal operation.
Remember that the current flow must return back to the substation (or the generator) for the electricity to work.
How electrical shocks happen
(a) When two wires are at two different voltages and they come into contact with each other, a current will pass through them.
If they are not in contact, but your body connects the two wires by touching both of them at the same time, then an electric current will pass through your body and you will get the shock.
(b) If you accidentally touch the energized LIVE wire or other, live parts of an energized electrical appliance, while another part of your body is also in contact with the NEUTRAL wire, a current will pass through your body. Then you will get an electric shock.
(c) If your body is in contact with the LIVE wire, while another part is touching a grounded object, you will also get an electric shock.
(Notes: A grounded object is:
1. Anything that in good contact with earth mass, like water pipes. Most authorities require that water pipes be grounded. However, even if some pipes are not grounded, the pipes that are laid partly or wholely underground (i.e. the mater mains coming to the house) are actually in good contact with earth mass.
2. Or anything that is purposely connected to the earth mass, like the street lamp posts in front of the house. Do not be fooled by the innocent-looking lamp posts, the compound lighting posts or the short bollard lighting posts at the park or by the street in front of the house. Many grown adults have actually been electrocuted and died just by leaning to the metal posts.
3. Or anything that is electrically connected to the house earth wires, like the metal conduit, the metal casing of the washing machines, etc.)
(d) There is a much higher risk of electric shock if you are standing in a pool of water. For example when your kitchen floor is all wet with water from the overflow at the kitchen sink, or while you are cleaning your kitchen floor with water. Worst still if the wet floor is at the living room because the a few power outlets there are normally installed at lower level (approximate 12 inches above floor level).
(e) The chances of being electrocuted will be much higher under certain conditions like wet clothing, high humidity and perspiration. Under these conditions the human skin is wet. This drastically reduce the resistance at the contact point where the electrified object touches the skin. The magnitude if the shock current is inversely proportional to the overall resistance of the human body, which include the skin contact resistance. Therefore, a more wet skin will direcly cause a higher current and a more severe electrical shock.
(f) An electrical equipment that is not properly grounded also can cause a shock. This is actually a shock from electrical outlet. It can happen when an electrical appliance cord has a 3-pin plug, but you attach a plug adapter to it so you can plug it into a 2-pin socket. Then the supply to the appliance no longer has the connection to the ground. The Earth Leakage Circuit Breaker at the home electrical panel will not trip if a live wire inside the appliane is faulty and it come into contact with the metal casing.
(g) If you touch a person who is receiving a shock, you will also get the shock. So, if you suspect that a person is down because of electric shock, do not rush to go and touch victim.
1. Low voltage does not mean it is not dangerous. A normal household electricity is either 110 Volt or 230 or 240 volt. These are what we normally call low voltage, and they are the voltages that have caused deaths at homes all this while.
2. High voltage in household terms is what we call the 600 volt level or higher voltage. But they are almost never found at homes, only at work or in factories.
3. However, that does not mean you can never get high voltage electric shocks at home. The conventional televisions (now the LCD televisions are taking over) with the cathode ray tubes are actually a machine with 11,000 volts electricity inside them. If one of your household members like repairing, testing or playing DIY with one of these TV sets, better give him a separate room just for himself, fully lockable.)
Electricity is dangerous. Whenever you use electrical appliances and equipment whether at home or at work, there is always a risk of hazards, especially of getting electric shocks.
A person gets an electric shock when a current passes through the body.
The higher the current that flow through the body, and the longer it flows through, the more serious the injuries. One hundred mili-ampere (100 mA) of current flow (that is one tenth of an ampere, or 0.1 Ampere) through the body will be enough to kill a person in just 2 seconds.
Hopefully after reading this article you can better appreciate how electric shock can happen in your daily lives. This can help you recognize, evaluate and control the hazards that come from electrical appliances and equipment in your daily routines.
Read Part 3 for details on home shock protection. Part 2 will explain on various types of injuries that will result if you get electrical shocks.
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