NCCER Maintenance & Repair 3 — Questions and Answers
Question 1: When caulking a bathtub surround, why should the tub be filled with water before applying caulk?
- To clean the surface before adhesion
- To weigh down the tub so it doesn't flex and crack the new caulk under load (Correct answer)
- To check for drain leaks before sealing
- To soften old caulk for easier removal
Correct answer: To weigh down the tub so it doesn't flex and crack the new caulk under load
Filling the tub with water simulates the loaded weight so the caulk cures in the expanded position, preventing cracking when the tub is used.
Question 2: A circuit breaker trips repeatedly under normal load. After ruling out overloading, what is the next most likely cause?
- The breaker is rated too high for the wire gauge
- A loose or corroded wire connection causing resistance heat (Correct answer)
- The panel is not properly grounded
- The neutral wire is connected to the wrong bus bar
Correct answer: A loose or corroded wire connection causing resistance heat
Loose or corroded connections create resistance that generates heat, causing the thermal element of the breaker to trip under normal current.
Question 3: When replacing ceramic floor tile, why is it important to use tile spacers during installation?
- To prevent the tile adhesive from drying too quickly
- To ensure uniform grout joint width and proper tile alignment (Correct answer)
- To keep the tile from sinking into the mortar bed
- To allow for thermal expansion of the subfloor only
Correct answer: To ensure uniform grout joint width and proper tile alignment
Tile spacers maintain consistent joint width for uniform grout lines and keep tiles properly aligned during the setting process.
Question 4: What is the primary purpose of a P-trap installed beneath a sink drain?
- To filter debris before it enters the drain line
- To hold a water seal that blocks sewer gases from entering the living space (Correct answer)
- To reduce water flow pressure from the drain
- To allow cleanout access without disassembling the drain line
Correct answer: To hold a water seal that blocks sewer gases from entering the living space
The curved P-trap retains a small amount of water that acts as a seal, preventing harmful sewer gases from rising through the drain into the building.
Question 5: When painting over a water-stained ceiling, what must be applied before the finish coat to prevent bleed-through?
- A coat of flat latex paint in a similar color
- Oil-based or shellac-based stain-blocking primer (Correct answer)
- Two coats of standard latex primer
- Diluted joint compound to seal the stain
Correct answer: Oil-based or shellac-based stain-blocking primer
Oil-based or shellac-based stain-blocking primers seal water stains and tannin bleed-through that latex primers cannot block.
Question 6: A sliding window won't glide smoothly. After cleaning the track, what is the recommended next step?
- Replace the entire window frame
- Apply a dry silicone spray or wax to the track and rollers (Correct answer)
- Tighten all visible screws in the frame
- Add weatherstripping along the top rail
Correct answer: Apply a dry silicone spray or wax to the track and rollers
Dry silicone spray or paraffin wax lubricates the track without attracting dirt, allowing the rollers to glide smoothly.
Question 7: What does it mean when a smoke detector chirps with a single beep approximately every 60 seconds?
- The detector has sensed smoke and is in alarm mode
- The battery is low and needs replacement (Correct answer)
- The unit has malfunctioned and must be replaced immediately
- The detector is in test mode
Correct answer: The battery is low and needs replacement
A single chirp every 30–60 seconds is the standard low-battery warning signal for most residential smoke detectors.
NCCER Maintenance & Repair 3
When caulking a bathtub surround, why should the tub be filled with water before applying caulk?