Excavations of ___ or greater depth shall have trench safety systems in place.

• A. 3 ft
• B. 5 ft
• C. 6 ft
• D. 8 ft

Answer: (B)

Trench safety systems are required whenever an excavation becomes deep enough that a cave-in could trap a worker. The standard threshold is five feet. At that depth or greater, protective measures such as shoring, shielding, or sloping the trench walls must be in place to prevent collapse. This rule exists because the risk of a dangerous cave-in increases with depth, so implementing a protective system dramatically reduces the chance of serious injury. If the trench is shallower, a trench safety system may not be mandated, but safe work practices and daily inspections are still essential. So the depth at which trench safety systems are generally required is five feet.