Module 2 · Mandatory Measures (Lighting & Daylighting)
LPD basics, control types, daylight zones, and exterior shutoff rules electricians must meet every time.
What you’ll master
- Compute room-level and project-level LPD.
- Pick correct control logic (manual-on/vacancy, time switch, dimming).
- Map daylight zones and place sensors correctly.
- Ensure outdoor lighting has photocell/astronomical time control.
Email Instructor
Tip: keep a running table of fixture watts and areas for quick LPD checks.
Deep Dive
LPD (Lighting Power Density)
LPD = total lighting watts / area (ft²). Use nameplate/allowed methods per code for each luminaire. Compare to allowed LPD for the occupancy type.
Controls
- Vacancy/manual-on: user turns on, auto-off via sensor/time-out.
- Multi-level/dimming: stepped or continuous per space type.
- Time switch / schedule: required shutoff for many spaces.
- Daylighting: sensors in primary/secondary zones dim/step lights.
Outdoor
Provide photocell or astronomical time switch to shut off or reduce lighting when not needed.
LPD Quick Calculator
LPD Quick-Check
Worked Example
Open office 1,200 ft² with 24 fixtures × 40 W = 960 W. LPD = 960/1200 = 0.80 W/ft². Compare against allowed LPD for open office (check code table). Add daylight dimming if glazing qualifies.
Practice Quiz (8 items)
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