Final answer:
ACI standards generally recommend a minimum cover of 3 inches for a No. 5 reinforcing bar in cast-in-place concrete exposed to the earth to protect from corrosion and damage.
Step-by-step explanation:
The minimum cover for a No. 5 reinforcing bar in cast-in-place concrete exposed to the earth is typically 3 inches (75 mm) according to ACI (American Concrete Institute) standards. This cover is essential to protect the rebar from corrosion and mechanical damage, which can otherwise compromise the structural integrity of the concrete. It is important to adhere to this standard, especially in environments where the concrete will be in direct contact with the earth and possibly exposed to moisture and other corrosive elements.