$3\mathrm{.}2.$ If open cut can be performed on all sides, does it need to be designed by a Professional Engineer $($PE$)?$ Is there an edge that cannot be open cut with a proper setback and therefore requires a PE to design an excavation protection system have to be custom designed by a Professional Engineer? Describe the conditions that trigger this PE requirement. Include the OSHA depth limit in your answer. Justify your answer in a complete sentence.