Testing additional protection (regulation 612.10)
In ADS systems often, additional protection is specified by the IET Wiring Regulations or the installation's designer, to enhance protection against electric shock. The verification of supplementary protective bonding is carried out during the continuity of protective conductors, 'dead' tests at the start of the sequence of tests. The term RCD is used to denote a residual current device, i.e. a device that operates based on the difference between the line and neutral currents. RCD testing is performed on the load side of the RCD, either at the RCD terminals directly or at a suitably accessible point on a final circuit. Many modern multi-function/RCD testers have an automatic RCD test, which will perform all the required tests automatically and then record the values for one to review after the test. In addition to the tests performed with the RCD tester, each RCD has a built-in test button to confirm the physical operation of the device and exercise the internal parts.