Accidents involving electric shocks are grouped into low voltage (up to 1,000 V alternating current/AC, up to 1,500 V direct current/DC) and high voltage accidents. Any effects of an electric current through the body depend on the type of voltage at the source, the pathway of the current in the body, the conductivity of the surface areas and the amount and duration of the flow of current. The current may affect electrically excitable and conductive structures, in particular the heart causing dysrhythmia, ventricular fibrillation and cardiac arrest, and also the nervous system und the blood vessels; in this respect AC is more dangerous than DC. Also thermal effects may be seen such as burns, necrosis of muscles and internal organs as well as secondary kidney failure. Currents through the body can involve a risk from about 30 mA AC and about 150 mA DC; such currents can be achieved under unfavourable circumstances even by contact with voltages as low as 25 V AC and 60 V DC; thus, according to the German Technical Rule for Industrial Safety and Health (TRBS) 2131, above these voltages an electrical hazard must be assumed under certain conditions. Dysrhythmia and ventricular fibrillation become evident immediately during or after the electric shock. After very short contact with a low voltage source, no further medical surveillance is needed, provided there are no abnormalities in medical history, physical or ECG examination. After high voltage accidents, necrosis of muscles and organ damage are to be expected, even after long latency periods; therefore, immediate and long term medical surveillance is mandatory in these cases.
