What does AC and DC stand for?
AC stands for alternating currents while DC stands for direct currents.
Dangers of
DC supply is more dangerous on the body and can cause more harm as it continuously flows in one direction whereas AC keeps on changing direction but is more dangerous to the heart. DC voltage can cause muscle spasms in one direction. For example, if you were touching an electrical fence with the bottom of your fingers, the shock causes your muscles to spasm and as a result, your fingers rap around the electric wire, sending in more shocks – in basic terms, you can’t let go. 240v AC has the same heating effect as a 240v DC current but AC voltage alternates as 240v is an average value; it is the potential between two phases of a three-phase distribution system. Whereas a 240v DC is the potential between and single wire and ground. Both AC and DC voltages can cause burns, electrocution, shocks, muscle spasms, unconsciousness and in serious cases, death. Electrocution, by both AC and DC voltages, causes a violent disturbance of the nervous system, thus affecting all muscles of the body. It is most common when a person touched an active wire and there are two types of wire: the neutral wire and the active wire (hot wire). The neutral wire is connected to the earth at the power station and is maintained at earth potential because of this. The active wire is one of the wires that bring electricity from the power station to the house, making it more dangerous. Electric currents can cause the muscles to contract. This is especially dangerous if the muscles that are contracting are required for breathing - it can cause breathing to cease and this can lead to death. However, the effects of mains AC currents on the heart are more complicated. Fibrillation can be caused by AC mains and is when the heart stops beating regularly and oscillates rapidly, and cannot pump blood, meaning death follows in minutes. Currents above 200 mA (milliamps) will not cause fibrillation, but will cause the heart to clamp. This is where AC is more dangerous than DC because DC does not lead to fibrillation. Both are lethal but more DC current is required to have the same affect as AC current at the same voltage but deep tissue burns are common in DC shocks than compared to AC shocks. Therefore, AC current is more dangerous to the heart and DC current is more dangerous to the body, specifically human flesh.