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.
The TN-CMCA exam has 100 questions and runs 5 hours.
These 10 free TN-CMCA questions are organized by exam domain, so you can see how each part of the Tennessee Plumbing (CMC-A) Contractor Examination blueprint is tested. Reveal the answer and explanation under each question.
Before drywall is installed, an inspector finds a CPVC line bored through a wood stud with the pipe surface 1.25 inches from the nearest face. The pipe cannot be rerouted. What protection should be installed before the wall is closed?
Correct answer: B - A steel shield plate at least 0.0575 inch thick over the vulnerable area
Finished dimensions inside a shower are 28 inches by 48 inches. The verified interior cross-sectional area is 1,344 square inches, and that area is maintained to 70 inches above the drain. No door intrudes into the required space. The inspector should:
Correct answer: C - Accept it because an area of at least 1,300 square inches permits a minimum dimension of 25 inches
A storage water heater's temperature-and-pressure relief valve drips briefly near the end of each heating cycle. Cold static pressure is 68 psi, outlet temperature is normal, and a new backflow preventer has made the system closed. The relief valve and discharge piping are correctly rated and installed. The first diagnostic check should focus on:
Correct answer: C - Verify the expansion tank's connection, size, precharge, and condition
A low-pressure natural-gas system uses the longest-length method. The most remote outlet is 100 feet from the meter. Segment A-B supplies a 90,000-Btu/h furnace, a 50,000-Btu/h water heater, and a 65,000-Btu/h range. Gas heating value is 1,000 Btu/ft3. At the 100-foot row, Schedule 40 pipe capacities are 1/2 inch = 50 CFH, 3/4 inch = 104 CFH, 1 inch = 195 CFH, and 1-1/4 inches = 400 CFH. Select the minimum compliant size for A-B.
Correct answer: B - 1-1/4 inches - 400 CFH
A competent person inspects a 4-foot-6-inch-deep trench in Type B soil before the shift and finds no indication of a potential cave-in. Spoil is 3 feet from the edge, and a secured ladder is within 20 feet of the workers. Based only on these conditions, how much additional cave-in protection is required because of depth?
Correct answer: D - No additional protective system on the stated findings
An isometric shows segment A-B carrying a 2-DFU sink drain. A separate 5-DFU bathroom-group line crosses A-B on the page. The drawing legend states that intersecting lines connect only when marked by a dot or fitting, and this crossing has neither. Segment B-C continues from the sink toward the stack. The load assigned to B-C is:
Correct answer: B - 2 DFU - the sink load only
A pipe must shift 9 inches vertically and 12 inches horizontally. The offset will be made with two 45-degree fittings. Calculate the center-to-center travel between fittings, rounded to the nearest tenth of an inch.
Correct answer: C - 21.2 inches - using the true offset before multiplying
A boiler makeup connection is subject to continuous pressure. Treatment chemicals in the boiler create a high-hazard contamination risk, and boiler pressure can exceed the potable supply pressure. The design requires an in-line testable assembly rather than an air gap. Which assembly satisfies both the hazard and pressure conditions?
Correct answer: A - Reduced-pressure-principle assembly (RPZ)
During rough-in, a 2-inch horizontal fixture drain must enter a 3-inch horizontal branch through a 90-degree change in direction. The installer has laid a sanitary tee on its back. Which revision provides the proper directional sweep for solids-bearing horizontal flow?
Correct answer: D - Replace it with a combination wye and 1/8 bend oriented with the flow
A seldom-used mechanical-room floor drain develops sewer odor every few weeks. The odor disappears as soon as water is added to the trap, the drain flows freely, and no leakage is visible. Which repair addresses the failure mechanism rather than merely masking the odor?
Correct answer: A - Restore the trap seal and repair or add an approved trap primer
The TN-CMCA exam also covers these domains. Drill them in the full free practice test:
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