Commercial & Industrial Systems
Three-phase power, transformers, and conduit bending math — the section that separates residential wiremen from commercial journeymen.
What to expect
Open book; three-phase calculations dominate.
The √3 factor (1.732) appears constantly — in power, current, and voltage conversions.
Bending questions test geometry: multipliers, shrink, and travel.
Pass mark: 70%.
How to study
→ Drill 120/208 V and 277/480 V systems until the phase-to-neutral relationship is reflex: line ÷ √3.
→ Memorize the offset multiplier table (30° → 2.0 is the workhorse).
→ When a question mixes single- and three-phase, write down which formula family you're in before computing.
Units in this certificate
Three-phase power: wye, delta, and √3
Conduit bending math: offsets and multipliers
Transformers: ratios, kVA, and connections
Motors: FLC, protection, and sizing
Motor control circuits and ladder logic
Conduit fill and raceway sizing
Overcurrent coordination and interrupting rating
Power factor and the power triangle
Practice exam
Each attempt draws 30 questions at random from the 44-question bank, so no two sittings are the same. Unanswered questions score zero, and the exam auto-submits when the clock runs out — just like the real thing. That works out to about 90 seconds per question.