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Grounding & Bonding Flashcards

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

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  1. What is the primary purpose of an equipment grounding conductor (EGC) in an electrical circuit?

    Answer: To provide a low-impedance fault current path so overcurrent devices can operate

    EGCs provide a low-impedance path for fault current, enabling overcurrent protective devices to clear the fault quickly and safely.

  2. According to NEC Table 250.122, what is the minimum copper equipment grounding conductor size for a branch circuit protected by a 20-ampere overcurrent device?

    Answer: 12 AWG

    NEC Table 250.122 requires a minimum 12 AWG copper EGC for circuits protected by overcurrent devices rated up to 20 amperes.

  3. Per NEC 250.56, when must a supplemental ground rod be added to a grounding electrode system?

    Answer: When a single rod electrode has a measured resistance exceeding 25 ohms to earth

    NEC 250.56 requires a supplemental electrode if the resistance of a single rod to earth exceeds 25 ohms.

  4. What is the minimum length required for a driven rod electrode per NEC 250.52(A)(5)?

    Answer: 8 feet

    NEC 250.52(A)(5) specifies that rod electrodes must be at least 8 feet (2.44 m) in length.

  5. What is the key difference between a grounded conductor and an equipment grounding conductor?

    Answer: A grounded conductor carries normal load return current; an EGC carries fault current

    The grounded conductor (neutral) carries normal return current under load, while the EGC provides a fault current path during a ground fault.

  6. Which of the following qualifies as an acceptable grounding electrode under NEC 250.52(A)(1)?

    Answer: A metal underground water pipe with at least 10 feet in direct contact with the earth

    NEC 250.52(A)(1) permits a metal underground water pipe with at least 10 feet of direct earth contact as a grounding electrode.

  7. Per NEC 250.119, which of the following is an acceptable identification for an equipment grounding conductor?

    Answer: Green insulation, bare conductor, or green insulation with yellow stripes

    NEC 250.119 permits EGCs to be identified by green insulation, bare copper, or green insulation with one or more yellow stripes.

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