North Carolina Building Contractor License Practice Exam

The correct answer is that the bottom of the trench box should be no higher than 5 feet above the pipe. This regulation is in place to ensure safety while maintaining structural integrity during excavation work. When the trench box is positioned at a specific height above the pipe, it helps to prevent soil from collapsing into the trench, which could pose significant hazards to workers and equipment below.

Maintaining a height limit of 5 feet prevents excessive strain on the sidewalls of the trench that could lead to instability. Additionally, this height allows for sufficient space to work around the pipe while also ensuring compliance with safety standards established for trenching operations. Proper trench box placement mitigates risks such as cave-ins or falls, making it a critical aspect of excavation safety practices.

By adhering to this guideline, contractors can help safeguard both their crew and the construction project, reinforcing the importance of following established protocols for trench safety.