LLC Landscape Lighting Electrical Wiring & Installation 3 — Questions and Answers
Question 1: Which NEC article primarily governs the installation of outdoor low-voltage lighting systems (under 30V)?
- Article 230
- Article 300
- Article 411 (Correct answer)
- Article 700
Correct answer: Article 411
NEC Article 411 covers lighting systems operating at 30 volts or less, which includes most low-voltage landscape lighting systems.
Question 2: When connecting a low-voltage transformer to a 120V household circuit, the transformer must be plugged into or hardwired to a circuit that is:
- Protected by a standard 15A breaker only
- GFCI-protected when installed in an outdoor or damp location (Correct answer)
- On a dedicated 20A circuit regardless of load
- Unprotected to avoid nuisance tripping
Correct answer: GFCI-protected when installed in an outdoor or damp location
NEC requires GFCI protection for outdoor receptacles and any outlet in damp or wet locations where a landscape transformer would be installed.
Question 3: A hub-and-spoke (homerun) wiring layout for landscape lighting offers what key advantage over daisy-chaining?
- Uses less total wire
- Provides more even voltage to all fixtures (Correct answer)
- Is easier to install in rocky soil
- Allows more fixtures per transformer tap
Correct answer: Provides more even voltage to all fixtures
Hub-and-spoke runs individual wires from a central junction point to each fixture, so every fixture receives nearly the same voltage from the transformer.
Question 4: What is the correct procedure when splicing low-voltage wire in a wet or buried location?
- Use standard twist-on wire connectors and wrap with vinyl tape
- Use UL-listed waterproof direct-burial splice connectors filled with silicone or dielectric gel (Correct answer)
- Solder the connection and cover with heat shrink tubing only
- Leave the splice above grade to allow inspection
Correct answer: Use UL-listed waterproof direct-burial splice connectors filled with silicone or dielectric gel
UL-listed waterproof direct-burial connectors with gel fill provide the moisture seal required for underground or wet-location wire splices.
Question 5: An installer measures 10.2V at a fixture that is supposed to receive 12V. What should be done FIRST to correct the problem?
- Replace the fixture with a lower-wattage model
- Move the transformer tap to a higher voltage setting (e.g., 13V or 14V tap) (Correct answer)
- Install a second transformer in series
- Reduce the total number of fixtures on the system
Correct answer: Move the transformer tap to a higher voltage setting (e.g., 13V or 14V tap)
Most multi-tap transformers have 12V, 13V, and 14V output taps specifically to compensate for voltage drop on longer runs.
Question 6: What does IP65 rating mean for a landscape lighting fixture?
- The fixture is safe for total submersion up to 65 meters
- The fixture is dust-tight and protected against water jets from any direction (Correct answer)
- The fixture operates on 65W maximum power
- The fixture has passed 65 hours of UV testing
Correct answer: The fixture is dust-tight and protected against water jets from any direction
IP65 means the enclosure is completely dust-tight (6) and protected against low-pressure water jets from any direction (5).
Question 7: When routing low-voltage landscape wire across a driveway, what installation method provides the best protection?
- Burying the wire 2 inches deep directly under the asphalt
- Running the wire through a rigid PVC conduit sleeve under the driveway (Correct answer)
- Stapling the wire to the driveway surface edge
- Using the wire's jacket as sufficient protection under paving
Correct answer: Running the wire through a rigid PVC conduit sleeve under the driveway
Running wire through a PVC conduit sleeve under driveways protects it from vehicle compression, frost heave, and future repairs.
LLC Landscape Lighting Electrical Wiring & Installation 3
Which NEC article primarily governs the installation of outdoor low-voltage lighting systems (under 30V)?