Practice Test Geeks(NECA) National Electrical Contractors Association Practice Test
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Electrical Systems & Equipment Flashcards

7 cards from real NECA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Electrical Systems & Equipment flashcards as text

  1. What is the minimum wire-bending space required inside a panel for a 350 kcmil conductor entering the side of a cabinet with one wire per terminal?

    Answer: 7 inches

    NEC Table 312.6(B) requires 7 inches of bending space for a 350 kcmil conductor entering the side of an enclosure with one wire per terminal.

  2. Which system automatically maintains constant voltage output despite variations in input voltage or load current?

    Answer: Voltage regulator

    A voltage regulator automatically adjusts to maintain a constant output voltage regardless of fluctuations in input voltage or load changes.

  3. In a 480Y/277V system, what voltage would be measured between any phase conductor and the neutral?

    Answer: 277V

    In a 480Y/277V wye system, the phase-to-neutral voltage is 480V divided by √3 = 277V.

  4. What is the purpose of an equipment grounding conductor (EGC)?

    Answer: Provides a low-impedance fault current path to operate overcurrent protection

    The EGC provides a low-impedance return path for fault current, ensuring overcurrent devices trip quickly when a ground fault occurs.

  5. What does a wattmeter measure in an AC circuit?

    Answer: True (real) power in watts

    A wattmeter measures true (real) power, which accounts for the phase angle between voltage and current in AC circuits.

  6. When installing a Variable Frequency Drive (VFD), why must the output conductors be kept short or use inverter-rated cable?

    Answer: Long cable capacitance causes reflected voltage spikes that damage motor windings

    Long cable runs from VFDs create capacitive charge that generates voltage reflection (standing waves), which can spike to twice the DC bus voltage and damage motor insulation.

  7. What is the correct color code for a high-leg (wild leg) conductor in a 240V delta system with a center-tapped neutral?

    Answer: Orange

    NEC 230.56 and 408.3(E) require the high leg (wild leg) of a 4-wire delta system to be identified with orange color because it has approximately 208V to neutral.