Which device is often used in explosive ordnance to prevent accidental detonation?

The safety pin is a crucial component in many explosive ordnance systems designed to prevent accidental detonation. It serves as a mechanical safety mechanism that keeps the firing mechanism in a safe condition until the device is intended to be activated. Typically, the safety pin is inserted into a mechanism that would otherwise allow the explosive device to fire or detonate. By keeping the pin in place, it effectively secures the device and ensures that it cannot be triggered unintentionally, providing a method to safely handle or transport ordnance until it is ready for use.

In contrast, safety knobs, impact switches, and protective casings each serve other necessary functions within explosive systems but do not act as a primary mechanical safety feature like the safety pin. Safety knobs may adjust settings or act as control mechanisms, impact switches are designed to activate devices upon receiving a specific force, and protective casings safeguard the integrity of the explosive; however, they do not directly prevent accidental initiation in the way a safety pin does. The function of the safety pin in maintaining safety during handling is a key reason for its importance in explosive ordnance disposal practices.