LLC Installation Techniques 3 — Questions and Answers
Question 1: When calculating the load for a 150-watt low-voltage transformer, what is the maximum total wattage of fixtures that should be connected to stay within the 80% rule?
- 90 watts
- 120 watts (Correct answer)
- 135 watts
- 150 watts
Correct answer: 120 watts
The 80% rule limits connected load to 80% of transformer capacity; 80% of 150W = 120W to prevent overheating and extend transformer life.
Question 2: Which type of landscape light fixture is most appropriate for wash-lighting a masonry retaining wall from a distance of 1–2 feet?
- Bullet spotlight with narrow 10° beam
- Well light aimed straight up
- Flood fixture with a 60° beam angle (Correct answer)
- Pendant fixture hung from overhead wire
Correct answer: Flood fixture with a 60° beam angle
A flood fixture with a wide 60° beam covers the broad surface of a retaining wall evenly when placed 1–2 feet away.
Question 3: When installing fixtures in a zone with significant elevation changes, voltage drop will be MOST severe at:
- The fixture closest to the transformer
- The fixture at the highest elevation on the longest cable run (Correct answer)
- The fixture at the lowest elevation
- All fixtures equally regardless of distance
Correct answer: The fixture at the highest elevation on the longest cable run
Voltage drop increases with cable length; the fixture farthest from the transformer on the longest run—often at the highest elevation—will experience the greatest drop.
Question 4: Which wire gauge carries the most current and is preferred for long landscape lighting runs exceeding 100 feet?
- 18 AWG
- 16 AWG
- 14 AWG
- 12 AWG (Correct answer)
Correct answer: 12 AWG
12 AWG has the lowest resistance of the common landscape wire sizes, making it best suited for long runs to minimize voltage drop.
Question 5: When installing an in-ground well light in a lawn area, what feature should the fixture have to withstand regular lawn mower traffic?
- A plastic housing for flexibility
- A tempered glass or polycarbonate flush-mount lens rated for drive-over loads (Correct answer)
- A raised housing that sticks up 2 inches above grade
- No special requirement beyond waterproofing
Correct answer: A tempered glass or polycarbonate flush-mount lens rated for drive-over loads
Well lights in trafficked areas must have a flush-mount tempered or polycarbonate lens rated to handle the compressive load of lawn equipment.
Question 6: What is 'moonlighting' as an installation technique in landscape lighting?
- Installing fixtures along a moonlit path to supplement natural light
- Mounting fixtures high in tree canopies to cast downward dappled light mimicking moonlight (Correct answer)
- Using blue-tinted LEDs for nighttime ambiance
- Wiring fixtures so they only activate when the moon is visible
Correct answer: Mounting fixtures high in tree canopies to cast downward dappled light mimicking moonlight
Moonlighting places fixtures high in trees aimed downward so light filters through leaves, recreating the soft, dappled quality of natural moonlight.
Question 7: Which of the following materials should NOT be used as conduit for underground landscape lighting cable near salt-water coastal environments?
- Schedule 40 PVC
- HDPE flexible conduit
- Galvanized rigid metal conduit (Correct answer)
- ENT (smurf tube) plastic conduit
Correct answer: Galvanized rigid metal conduit
Galvanized steel conduit corrodes rapidly in salt-air or salt-soil coastal environments; non-metallic conduits like PVC or HDPE are preferred.
LLC Installation Techniques 3
When calculating the load for a 150-watt low-voltage transformer, what is the maximum total wattage of fixtures that should be connected to stay within the 80% rule?