Practice Test Geeks(E2) E2 Commercial Electrical Inspector Practice Test
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Services, Feeders, Branch Circuits Flashcards

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Read the first 7 Services, Feeders, Branch Circuits flashcards as text

  1. Per NEC 230.46, which service entrance conductors are required to have mechanical protection where subject to physical damage?

    Answer: All service entrance conductors

    NEC 230.46 requires all service entrance conductors subject to physical damage to be protected.

  2. A feeder tap conductor is installed in a commercial building. Per NEC 240.21(B)(2), a feeder tap conductor up to 25 feet long must have an ampacity of at least what fraction of the upstream overcurrent device rating?

    Answer: 1/3 (one-third)

    NEC 240.21(B)(2) requires the 25-foot tap conductor to have an ampacity of at least one-third of the rating of the overcurrent device protecting the feeder.

  3. Which of the following is a permitted use of a 15-ampere branch circuit in a commercial building per NEC 210.23(A)?

    Answer: Supplying lighting outlets and up to 15-ampere receptacles

    NEC 210.23(A) permits 15-ampere branch circuits to supply lighting outlets, cord-and-plug equipment, and receptacles not exceeding 15 amperes.

  4. Per NEC 215.12, feeder conductors must be identified by means of:

    Answer: Field-applied markings at each end and at accessible points

    NEC 215.12 requires feeder conductors to be legibly marked at terminations and wherever accessible using field-applied identification.

  5. What is the maximum unprotected length of service entrance conductors permitted inside a building before reaching the service disconnecting means per NEC 230.70 and 230.6?

    Answer: Conductors must be considered outside even when encased in concrete or masonry

    NEC 230.6 permits service conductors encased in 2 inches of concrete or masonry to be considered outside the building, effectively allowing them to reach the disconnect without the 'inside' restrictions.

  6. For a 3-phase, 4-wire, 208Y/120V commercial feeder, how is the neutral conductor load calculated when the load consists entirely of balanced 3-phase line-to-line loads?

    Answer: The neutral carries zero current for balanced 3-phase loads

    In a balanced 3-phase system, line-to-line loads produce equal and opposite currents that cancel in the neutral, resulting in zero neutral current.

  7. Per NEC 230.54, service entrance cable used as an overhead service drop attachment to a building must be arranged to:

    Answer: Form a drip loop before entering the weatherhead

    NEC 230.54(C) requires service entrance conductors to be arranged to form a drip loop below the service head to prevent water entry.