LLC Landscape Lighting Electrical Wiring & Installation 2 — Questions and Answers
Question 1: When installing low-voltage landscape lighting wire underground, what is the minimum burial depth required by most local codes?
- 2 inches
- 4 inches
- 6 inches (Correct answer)
- 12 inches
Correct answer: 6 inches
Most codes require low-voltage landscape wire to be buried at least 6 inches deep to protect it from accidental damage.
Question 2: A customer's landscape lighting keeps tripping the GFCI outlet. What is the MOST likely cause?
- Too few fixtures on the circuit
- Moisture intrusion into a fixture or connection (Correct answer)
- Wire gauge is too large
- Transformer is overrated for the load
Correct answer: Moisture intrusion into a fixture or connection
GFCI trips in outdoor lighting are most commonly caused by moisture entering fixtures or wire connections, creating a ground fault.
Question 3: What does the term 'voltage drop' mean in the context of a low-voltage lighting system?
- The transformer stepping down 120V to 12V
- The reduction in voltage along the wire run due to resistance (Correct answer)
- The voltage lost when a fixture burns out
- The surge protector limiting peak voltage
Correct answer: The reduction in voltage along the wire run due to resistance
Voltage drop is the reduction in voltage that occurs along a wire run because the wire's resistance consumes some electrical energy.
Question 4: Which wire connection method is BEST for outdoor underground low-voltage landscape lighting splices?
- Standard wire nuts
- Waterproof gel-filled connectors (direct-burial connectors) (Correct answer)
- Electrical tape wrapping only
- Twist-and-tape butt splice
Correct answer: Waterproof gel-filled connectors (direct-burial connectors)
Waterproof gel-filled direct-burial connectors seal out moisture and are rated for underground use, preventing corrosion and ground faults.
Question 5: When using a daisy-chain (series) wiring method for landscape lights, where do the fixtures with the MOST voltage drop appear?
- At the beginning of the run nearest the transformer
- In the middle of the wire run
- At the end of the wire run farthest from the transformer (Correct answer)
- Voltage drop is uniform throughout a daisy-chain run
Correct answer: At the end of the wire run farthest from the transformer
In a daisy-chain layout, each successive fixture receives slightly less voltage, so fixtures at the farthest end experience the greatest voltage drop.
Question 6: What is the PRIMARY advantage of using 12/2 wire instead of 16/2 wire for a long landscape lighting run?
- It is cheaper per foot
- It has lower resistance, reducing voltage drop over distance (Correct answer)
- It is easier to bury underground
- It supports a higher voltage rating
Correct answer: It has lower resistance, reducing voltage drop over distance
Larger wire gauges (lower AWG numbers) have less resistance per foot, which significantly reduces voltage drop on long runs.
Question 7: A landscape lighting transformer is rated at 150W. The installer wants to add fixtures totaling 120W. What percentage of the transformer capacity is being used?
- 60%
- 75%
- 80% (Correct answer)
- 90%
Correct answer: 80%
120W ÷ 150W = 0.80, or 80% of transformer capacity, which is within the recommended maximum of 80% loading.
LLC Landscape Lighting Electrical Wiring & Installation 2
When installing low-voltage landscape lighting wire underground, what is the minimum burial depth required by most local codes?