An industrial facility has a solar water heating system with a storage tank volume of 1000 gallons. What is the minimum size of the overfill vent required for the storage tank, according to 2026 NEC Article 490.31(A)?
- A3/4 inch
- B1 inch
- C1 1/4 inch
- 1 1/2 inch
Exam tip
Always refer to the specific volume requirements for overfill vents in the NEC.
Why D is correct
According to 2026 NEC Article 490.31(A), the minimum size of the overfill vent for a storage tank with a volume of 1000 gallons is 1 1/2 inch. Options a, b, and c are smaller than the minimum required for this tank size.