Testing methods and equipment for earthing should be documented. Supplementary equipotential bonding should be checked annually and recorded in the O&M manuals for the periodic inspector; in high-risk clinical areas with invasive procedures validation should be at most 12-monthly and after any nearby alterations, recording bonding, extraneous metalwork and outlet resistances to the EBB and investigating differences from commissioning. The PES and any secondary supply should not degrade the earth platform. Mobile facilities and mobile generators should have their connection, earth and impedance values tested each time, with certificates before connection. Lightning systems should be inspected and tested annually to BS EN 62305 (each electrode satisfactory, overall not above 10 ohms, interval plus a month to cover seasons). Disconnecting main earths needs a monitored jumper rated for fault current and a permit-to-work.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.