OSHA Standard 29 CFR Part 1926 Subpart P is the part of the Federal Standard that deals with excavations. Under 1926.652 “Requirements For Protective Systems” it is stated: “(1) each employee in an excavation shall be protected from cave-ins by an adequate protective system designed in accordance with paragraph (b) or (ac) of this section except when (i) Excavations are made entirely in stable rock; or (ii) Excavations are less than 5 feet (1.52m) in depth and examination of the ground by a competent person provides no indication of a potential cave in”.
!["A" Series Trench Shields](http://www.gproadwaysolutions.com/sites/default/files/imagecache/thumbnail_100x100_scale/category_pictures/8inchSteel.jpg ""A" Series Trench Shields")
