Low Voltage (SELV) is defined as the low voltage that must not exceed a certain voltage level between two touchable conductive points. Circuits with safety extra low voltage must be separated from circuits with high voltage by reinforced insulation. Therefore, safety extra-low voltages provide special protection against electric shock.
Safety extra-low voltages are so low that the current generated by the human body when touched does not cause any health effects. The maximum voltage level for safety extra-low voltages or protective extra-low vol tages is 60 V.