There are many dangers associated with electricity. The real danger with electrical shock is amperage, not voltage. Although people have been killed by as little as 120-volt AC and low-voltage DC, the silent killer is the amount of amperage, measured in milliamperes, that flows through a person's body. Any electrical device is capable of dealing a deadly blow, depending on the amount of current flowing through it.
In fact, a dose of current in the 100-200 milliamperes range is likely to be fatal.
Effects of Amperage on Electrical Shock
Different amounts of amperage affect the human body in different ways. The following list explains some of the most common effects of electrical shock. To understand the amounts involved, a milliampere (mA) is one thousandth of on ampere or amp. A standard household circuit that supplies your outlets and switches carries 15 or 20 amps.
- 1-10 mA
The person will feel little or no electrical shock effects or sensation.
- 10-20 mA
The painful shock will occur like a jolt, but muscle control will not be lost at this amperage.
- 20-75 mA
This shock is more serious. You'll receive a painful jolt and muscle control will be lost resulting in the inability to let go of something you may have grabbed that is shocking you.
- 75-100 mA
As the current approaches 100 milliamperes, ventricular fibrillation of the heart occurs and damage is done.
- 100-200 mA
Ventricular fibrillation occurs and death can occur if medical attention is not administered quickly.
- Over 200 mA
Severe burns and severe muscle contractions occur. Your heart can stop during a shock because the chest muscles put pressure on the heart. Internal organs can be damaged at this stage and in you survive, a painful recovery can be expected. What may surprise you about this level of shock is that through this clamping effect on the heart, ventricular fibrillation is avoided and the chances of a person's survival are good if the victim is removed from the electrical circuit.
You should always practice electrical safety when doing any electrical project. There are many safety techniques and practices to follow to help keep you safe. Let's look at a few of them now to ensure your safety.
Working with electrical circuits can be dangerous if you don’t take certain safety precautions. Electrical shock can not only injure you but also kill you. Practice safety when working on any circuit, and slow down! When you hurry through a project, there is a greater chance for an accident to occur.
Shut the Power Off
Always shut off the power to a circuit or device that you will be working on. This is the first thing you should do before working on any electrical circuit. I don’t know anyone who has been shocked by a circuit that is not energized.
Test the Circuit
After turning a circuit off by switching off the breaker at the electrical service panel (breaker box), it's a good idea to check it with a tester to be sure that it is off. Never assume that the circuit is off!
Ladders are necessary to accomplish some electrical jobs. Never use an aluminum ladder on any electrical project. Always use an insulated fiberglass ladder to keep you safe.
Avoid wet areas when working with or on anything electrical. If there is a reason that you have to be in that situation, wear rubber boots and gloves to reduce the chance of getting shocked. Tools and appliances should be plugged into a GFCI (ground-fault circuit-interrupter) outlet or GFCI extension cord. Also, don't forget to dry your hands before grabbing any cord to plug it in or unplug it. Wet hands and a frayed cord don't mix.
Finally, if you are working on the service panel or a circuit, be sure to place a warning label on the face of the panel. This will warn someone not to turn on the circuit that you are working on. There’s nothing worse than turning off the power, checking that it’s off and starting to work on the circuit, only to have someone come behind you and turn the circuit back on. Always think and ask questions before turning on a breaker that is shut off. Maybe someone is working on the other end.