Use at least one visual and one manual soil test to determine soil type.
A Ladder is required for access and egress at 4’
The ladder must be within 25’ lateral travel at all times.
At 5’ depth some type of ‘protective system is required’.
Treat all soil as Type ‘C’ and slope at 1 _ : 1 and you are covered.
If not: Use some type of shoring or shielding to protect your employees.
Excavations over 20’ require the use of a P.E.