Capacitors can hold substantial energy when de-energized. Before work on them or their circuit wiring, capacitors and associated circuits must be proven de-energized and fully discharged, using and keeping in place safe discharging devices or following the maker's instructions; a voltage tester on its d.c. range must prove discharge immediately before work, because capacitors without discharge devices can recover full voltage. An undischarged capacitor is treated under the live work rules. Shorting or earthing terminals with spanners or screwdrivers should not be attempted; only suitable discharge devices should be used.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.