CLC CLC Residential Lighting Design 2 — Questions and Answers
Question 1: Which Title 24 requirement in California most directly affects residential lighting fixture selection?
- Mandatory use of daylight sensors in all rooms
- Minimum efficacy requirements and high-efficacy lamp mandates for most fixtures (Correct answer)
- Maximum wattage caps on decorative fixtures
- Requirement for DALI dimming in all new construction
Correct answer: Minimum efficacy requirements and high-efficacy lamp mandates for most fixtures
California Title 24 mandates high-efficacy lamps (typically LED) in the majority of residential luminaires to meet energy efficiency standards.
Question 2: A residential client complains that their dimmed LED downlights flicker noticeably. The most likely cause is which compatibility issue?
- The fixtures are too close together
- Mismatch between the LED driver and the legacy phase-cut (TRIAC) dimmer switch (Correct answer)
- The lamps have too high a CRI rating
- The CCT is too warm for the dimmer's range
Correct answer: Mismatch between the LED driver and the legacy phase-cut (TRIAC) dimmer switch
TRIAC/phase-cut dimmers designed for incandescent loads often conflict with LED drivers, causing flicker, buzzing, or dropout at low levels.
Question 3: For residential stairway lighting, which design principle is most critical for safety?
- Using only warm CCT lamps for aesthetics
- Eliminating shadows on tread nosings and maintaining adequate illuminance on all steps (Correct answer)
- Installing exclusively recessed fixtures in the ceiling
- Maximizing lumens to achieve the brightest possible stairway
Correct answer: Eliminating shadows on tread nosings and maintaining adequate illuminance on all steps
Stairway lighting must clearly reveal tread edges (nosings) and maintain uniform illuminance to prevent missteps and falls.
Question 4: Which mounting type is typically used for residential under-cabinet kitchen lighting to provide task illumination on countertops?
- Surface-mounted pendant
- Linear LED strip or puck lights mounted at the cabinet's front edge (Correct answer)
- Recessed downlight centered in the cabinet soffit
- Cove lighting above upper cabinets
Correct answer: Linear LED strip or puck lights mounted at the cabinet's front edge
Under-cabinet linear LED strips or puck lights installed near the front edge of wall cabinets cast light directly onto the countertop with minimal shadow.
Question 5: In residential bedroom design, which lighting strategy is recommended to minimize blue-light exposure before sleep?
- Using 5000K daylight lamps for maximum visibility
- Dimming to low levels with warm (2700K or below) CCT in the evening (Correct answer)
- Installing full-spectrum lamps for color accuracy
- Switching from LED to halogen sources at bedtime
Correct answer: Dimming to low levels with warm (2700K or below) CCT in the evening
Dimmed, warm-CCT light in the hours before sleep reduces circadian-disrupting blue-light exposure, supporting melatonin production.
Question 6: When installing recessed fixtures in an insulated ceiling, which IC (Insulation Contact) rating is required?
- Non-IC rated fixtures are acceptable if a barrier is installed
- IC-rated fixtures approved for direct contact with insulation (Correct answer)
- Any fixture rated for damp locations
- Fixtures must be rated Type 'AT' only
Correct answer: IC-rated fixtures approved for direct contact with insulation
IC-rated fixtures are required when they will be in direct contact with insulation, preventing overheating and fire hazards.
CLC CLC Residential Lighting Design 2
Which Title 24 requirement in California most directly affects residential lighting fixture selection?