What are the riskiest effects of improper installed and wrong repair of electrical? Often we hear of fires triggered by electricity. Many people have lost their lives due to electric shock. The main problem in studying electricity is not visible and can not be touched, even we do not want to touch it. We know there is electricity after seeing the consequences, like lights on, fan spinning, and radio sound. There are three dangers caused by electricity, namely string, heat or fire, and explosion.

Well, the electric shock will be felt if the electric current through our body. Usually the current will begin to be felt in the current flowing more than 5 mA. In small currents, current flow will only cause tingling or loss of ability to control the hand. In large currents, electric current can burn our skin and flesh. The most dangerous is if the current flow through the heart or brain. It should be noted that the harm is the flow of electricity, not the voltage. Although the voltage is high, it may not be dangerous as long as the current is very small.

The second danger is heat or fire. Heat appears because of the flow of current through a resistance. The amount of heat is proportional to the square of the current, the magnitude of the resistance, and the time. If we use a cable that is too small then the resistance is large so that the wire can be warmed up. The hot wire can cause the burning of cable insulation resulting in the occurrence of short circuit. Contact or imperfect connections can also cause heat to burn the insulation of cables. Closing the lights, closing the fan, closing the computer screen with the flammable material is also dangerous.

The third danger is the explosion. When there is a short circuit, the flow of electric current will be very large. Very large currents can cause a very rapid rise in temperature, causing a rapid rise in air pressure. For residential installations, these dangers may not be too large because the shortest possible flows are not too large.