CEA Grounding, Bonding, and Electrical Service Equipment Questions and Answers Flashcards

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

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

The EGC provides a low-impedance fault current return path so that a line-to-ground fault causes enough current to trip the overcurrent protective device quickly.

What is the difference between grounding and bonding?

Answer: Grounding connects the system to earth; bonding connects conductive parts together to equalize potential

Grounding establishes a reference connection to earth potential, while bonding electrically connects conductive parts together to eliminate voltage differences between them.

According to NEC Article 250, which conductor connects the grounded (neutral) conductor to the equipment grounding conductor at the service?

Answer: Main bonding jumper

The main bonding jumper (MBJ) connects the grounded conductor to the equipment grounding conductor and the service enclosure at the service equipment.

What is a grounding electrode conductor (GEC)?

Answer: The conductor that connects the grounded system conductor or equipment to the grounding electrode

The GEC connects the grounded service conductor (or equipment) to the grounding electrode system, establishing the earth connection.

Which of the following is a listed grounding electrode per NEC 250.52?

Answer: Concrete-encased electrode (Ufer ground)

A concrete-encased electrode (Ufer ground) — at least 20 feet of #4 AWG or larger bare copper or rebar encased in concrete — is a listed grounding electrode per NEC 250.52(A)(3).

When two or more ground rods are used as the grounding electrode system, what is the minimum spacing between them per the NEC?

Answer: 8 feet

NEC 250.53(B) requires ground rods to be spaced at least 6 feet apart, though greater spacing improves effectiveness.