Chapter 14: Electrical Design and Wiring

14.1 Why must electrical systems coordinate closely with architecture?

Electrical components (panels, conduits, outlets) are distributed throughout spaces → must align with walls, ceilings, and layouts to ensure access, safety, and aesthetics.;

14.2 What are the basic steps in electrical design? Must they be sequential?

Load estimation, system selection, distribution design, equipment sizing, layout, and detailing; generally follow logical order but may be iterative.;

14.3 How to determine gross and net demand loads?

Gross = sum of connected loads × demand factors; Net = gross/diversity factor → accounts for non-coincident peak usage.;

14.4 Minimum clearance for electrical equipment?

120-V panelboard: ~3 ft; 480-V switchboard (rear access): ~3–4 ft front/back; 4160-V controller: larger clearances (~5–6 ft) for safety.;

14.5 Methods to provide power away from walls?

Floor outlets, underfloor raceways, power poles, ceiling drops, raised-floor systems.;

14.6 Difference between schematic vs wiring diagram?

Schematic shows system logic; wiring diagram shows actual physical connections and layout.;

14.7 Branch circuits for multi-level lighting control?

Separate circuits for different lighting levels; use 3-way switches at both entrances to control multiple lighting states.;

14.8 How to design outlet wiring plan?

Sum loads per circuit (amps), ensure circuit capacity not exceeded, distribute outlets evenly across circuits.;

14.9 Why plan for future system capacity?

Allows expansion without major redesign; typical practice is to oversize equipment ~10–25%.;

14.10 Advantages of three-phase over single-phase?

More efficient, smoother power, less conductor material, better for large loads.;

14.11 What if new equipment has different voltage/phase?

Use transformers or converters to match system voltage/phase requirements.;

14.12 Should NEC be followed exactly?

Yes as minimum standard; can exceed for better safety/design but not go below.;

14.13 Minimum wire size for branch circuits?

Residential: typically #14 AWG; Institutional/commercial: often #12 AWG for durability and load.;

14.14 Max portable equipment on 30 A circuit?

80% rule → 24 A max continuous load (≈ 2880 W at 120 V).;

14.15 Is EMT allowed in floor/wet locations?

In floor: generally no unless protected; Wet locations: allowed if rated for wet use.;

14.16 Should all phases be in same conduit?

Yes; keeps magnetic fields balanced and prevents overheating.