Practice Test Geeks(E2) E2 Commercial Electrical Inspector Practice Test
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Grounding and Bonding Flashcards

7 cards from real E2 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Grounding and Bonding flashcards as text

  1. In a separately derived system from a transformer, where is the system bonding jumper installed?

    Answer: At the source of the separately derived system or at the first disconnect

    Per NEC 250.30(A)(1), the system bonding jumper for a separately derived system is installed at the source or at the first system disconnecting means.

  2. When parallel conductors are used, how must equipment grounding conductors be sized?

    Answer: Each parallel set must contain a full-size EGC based on the overcurrent device

    NEC 250.122(F) requires each parallel raceway or cable to include an EGC sized for the full rating of the overcurrent device protecting the circuit.

  3. What is the minimum size copper grounding electrode conductor permitted to be protected by installing it in conduit without increasing its size?

    Answer: 6 AWG

    NEC 250.64(B) permits 6 AWG and larger copper GECs to be installed without physical protection when they are securely fastened; smaller sizes require protection.

  4. What is the primary reason isolated grounding receptacles are used in commercial electrical installations?

    Answer: To reduce electrical noise on sensitive electronic equipment

    Isolated grounding receptacles provide a separate, noise-free ground path for sensitive electronic equipment by isolating the grounding terminal from the metal yoke.

  5. Under NEC 250.119, which identification method is used for equipment grounding conductors larger than 6 AWG?

    Answer: Green tape, green-colored markings, or bare conductor

    NEC 250.119(A) permits larger EGCs to be identified using green tape, green-colored marking, or bare conductors since green insulation is impractical at larger sizes.

  6. What grounding requirement applies to metal duct systems in a commercial HVAC installation per NEC 250.104?

    Answer: Metal ducts must be bonded to the building grounding electrode system

    NEC 250.104(C) requires metal duct systems to be bonded to the grounding electrode system to prevent dangerous voltage potential differences.

  7. When inspecting a commercial service, an inspector finds the neutral bar and equipment ground bar are bonded together in a subpanel fed from the main service. This is:

    Answer: A violation that creates parallel return paths for normal current

    NEC 250.142(B) prohibits bonding the grounded conductor to the equipment grounding terminal in subpanels; doing so creates objectionable parallel neutral current paths through grounding conductors.