Look at general issues of electrical safety.
Electric current on the human body.
Electrical system is to work done in high-risk. Operation of electrical equipment in terms of safety is very different from any other operation, no electrical equipment type.
Usually the threat of an accident on electrical equipment not accompanied by some signs, which can respond to human sense organs. View of the approaching transport, the smell of gas, rotating machine parts usually helps a person to take the necessary precautions. But for the detection of electric current at a distance a person has no special organ of sense. When servicing the electrical current and voltage do not show outward signs, so the human senses do not detect impending danger. The electric current strikes suddenly. Here, the threat makes itself known just after the person is under the influence of an electric current. In other words, a dangerous situation is detected too late, i.e., when to prevent electric shock practically it is impossible. Out of every 100 accidents investigated, related to electric shock, 90 in the death of the victim.
Depending on the value of current and time of exposure, as well as a number of other causes electric current passing through the human body can cause just discomfort, burns, fainting, convulsions, cessation of breathing and even death.