Only competent persons may test to prove de-energization, and any such voltage test must follow this order: visually check the tester for damage; confirm it suits the voltage present; prove it on a known live source; test between every conductor and a known earth; test between all conductors; and prove the tester again on a known source. Testers must be proved immediately before and after use, with particular care when the result is zero. Testers that sense the electric field around a conductor are unsuitable for screened cables, d.c. circuits and similar situations (AS/NZS 3017 gives further guidance).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.