Important terms/topics covered in this chapter: 

■ Earth electrode A conductor or group of conductors in intimate contact with and providing an electrical connection with earth

■ Earth fault loop impedance The impedance of the earth fault loop (line-to-earth loop) starting and ending at the point of earth fault

■ Residual current device (RCD) An electromechanical switching device or association of devices intended to cause the opening of the contacts when the residual current attains a given value under specified conditions

■ Ring final circuit A final circuit arranged in the form of a ring and connected to a single point of supply