Why Shock protection at a station is layered, and all three practices listed do real work. Three-wire grounded cords and plugs give equipment chassis a low-resistance path back to the service ground so a fault trips the breaker instead of energizing the case. Bonding all gear to a single common safety ground prevents dangerous voltage differences between chassis that you might bridge with your body. And high-voltage filter capacitors can hold a lethal charge long after power is removed, so they must be bled down and verified discharged before you reach inside.