Exemplary setup for keeping the engine running (clamp 15) without the ignition switch turned on.
The upper switch is the ignition switch (above 30, below 15), the lower one would be a switch on the dashboard to activate the continuos ignition. Without previously activating the "real" ignition switch, it is without function - all safety precautions can still perform their jobs. Both the relay and the lower switch need to be rated at or higher than the expected current.
