LLC Material Selection & Properties 2 — Questions and Answers
Question 1: Which connector material is most resistant to corrosion in coastal saltwater environments for landscape lighting?
- Zinc-plated steel
- Stainless steel 316 (Correct answer)
- Galvanized iron
- Tin-plated copper
Correct answer: Stainless steel 316
Stainless steel 316 contains molybdenum, which provides superior resistance to chloride corrosion found in coastal saltwater environments.
Question 2: What is the primary advantage of using silicone-insulated wire over PVC-insulated wire in landscape lighting applications near heat sources?
- Lower cost
- Higher temperature rating (Correct answer)
- Better UV resistance
- Easier to strip
Correct answer: Higher temperature rating
Silicone insulation can withstand temperatures up to 200°C, making it suitable for use near heat sources where PVC insulation would degrade.
Question 3: Which lens material provides the best impact resistance for pathway lights in high-traffic areas?
- Borosilicate glass
- Tempered glass
- Polycarbonate (Correct answer)
- Acrylic
Correct answer: Polycarbonate
Polycarbonate is virtually unbreakable compared to glass and acrylic, making it the best choice for high-traffic areas where physical impact is likely.
Question 4: When selecting transformer enclosure material for a wet location, which material offers the best combination of corrosion resistance and structural integrity?
- Fiberglass-reinforced polyester
- Painted mild steel
- Aluminum alloy (Correct answer)
- ABS plastic
Correct answer: Aluminum alloy
Aluminum alloy transformer enclosures resist corrosion naturally, provide excellent structural strength, and dissipate heat effectively in wet locations.
Question 5: What copper wire gauge has a current-carrying capacity of approximately 20 amperes for 12V landscape lighting circuits?
- 18 AWG
- 16 AWG
- 12 AWG (Correct answer)
- 10 AWG
Correct answer: 12 AWG
12 AWG copper wire is rated for approximately 20 amperes, making it appropriate for landscape lighting circuits requiring that capacity.
Question 6: Which gasket material is recommended for LED fixture housings that experience wide temperature swings from -20°F to 130°F?
- Neoprene
- Silicone (Correct answer)
- EPDM rubber
- Natural rubber
Correct answer: Silicone
Silicone gaskets maintain flexibility and sealing properties across the widest temperature range, from -65°F to over 400°F, outperforming other elastomers.
Question 7: What is the minimum IP rating required for landscape lighting fixtures installed below grade in water features?
- IP44
- IP55
- IP65
- IP68 (Correct answer)
Correct answer: IP68
IP68 is required for fixtures installed below grade in water features, as it indicates protection against continuous submersion under specified pressure.
LLC Material Selection & Properties 2
Which connector material is most resistant to corrosion in coastal saltwater environments for landscape lighting?