10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free NCPC questions are organized by exam domain, so you can see how each part of the North Carolina Plumbing Contractor License Exam (Class I) blueprint is tested. Reveal the answer and explanation under each question.
The plumbing rough-in is complete in a framed commercial tenant space, but the rough inspection and prescribed tests have not occurred. The drywall crew is ready to close the walls. What should the plumbing contractor do next?
Correct answer: C - Delay concealment until the rough inspection and required tests are approved
A nonaccessible shower compartment is shown with finished interior dimensions of 25.5 inches by 52 inches, an interior area of 1,326 square inches, and a 23-inch access opening. The proposed compartment is:
Correct answer: A - Compliant under the reduced-dimension shower exception
A storage water heater's T&P discharge pipe is full-size and has no valve or trap, but it rises 8 inches to clear a beam before descending to a receptor. Its open end is 4 inches above the receptor rim. Which correction is required?
Correct answer: D - Reroute the line to drain continuously by gravity without an uphill section
A remote shower requires 8 psi residual pressure. The source provides 62 psi static pressure. The shower is 35 feet above the source; use 0.433 psi loss per foot of rise. Meter and device losses total 7 psi. At design flow, the proposed pipe size loses 34 psi and the next larger size loses 24 psi. Which conclusion follows?
Correct answer: B - Increase one pipe size; allowable piping loss is about 31.8 psi
An irrigation system has a fertilizer injector, remains under continuous pressure, and can impose downstream backpressure on the potable supply. The appropriate protection is:
Correct answer: B - An ASSE 1013 reduced-pressure-principle assembly with an air-gapped relief discharge
Static pressure at a commercial building service is 96 psi. The design will add a pressure-reducing valve, and the meter assembly already contains a check valve. What is the code-compliant design response?
Correct answer: D - Use an ASSE 1003 PRV with strainer set to 80 psi or less, plus expansion control
A 44-foot run of 4-inch horizontal drainage pipe must slope at least 1/8 inch per foot. The installed invert elevations provide 5.25 inches of fall. How should the installation be evaluated?
Correct answer: A - Noncompliant by 0.25 inch; reset the pipe before concealment
A building drain at 1/8 inch per foot carries 18 DFU, including four water closets. The sizing table allows 36 DFU on 3-inch pipe and 180 DFU on 4-inch pipe, but limits a 3-inch horizontal drain to three water closets. What is the minimum permitted pipe size?
Correct answer: C - Use 4-inch pipe; the three-water-closet limit governs despite the available DFU capacity
A basement restroom backs up only when the public sewer surcharges. Its fixture flood-level rims are 18 inches below the next upstream manhole cover; all first-floor fixture rims are above that elevation. Which piping arrangement is correct?
Correct answer: D - Protect the basement branch with an accessible backwater valve; keep upper fixtures outside that valve
In a restaurant, a food-preparation sink has an indirect waste outlet with a 1.25-inch effective opening. The required air gap is at least twice the opening diameter. How should the sink be connected?
Correct answer: B - Terminate the outlet 2.75 inches above the receptor flood-level rim
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