inal Answer:
Excavations 20 feet and greater in depth must have a protective system that is planned and designed by a professional engineer.
Step-by-step explanation:
For excavations that reach a depth of 20 feet or more, it is a critical safety requirement to implement a protective system that has been carefully planned and designed by a professional engineer.
The design of such protective systems is crucial to ensuring the stability and integrity of the excavation site, preventing potential collapses or cave-ins. Professional engineers evaluate various factors, including soil composition, adjacent structures, and environmental conditions, to create a protective system tailored to the specific excavation project. This system typically includes components like shoring, sloping, or trench boxes, providing the necessary support and minimizing the risks associated with deep excavations.