Grounding and Bonding Flashcards
6 cards from real TN LLE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Grounding and Bonding flashcards as text
Per NEC 250.122, what is the minimum size equipment grounding conductor for a circuit protected by a 60-ampere overcurrent device?
Answer: 10 AWG
NEC Table 250.122 requires a minimum 10 AWG copper equipment grounding conductor for a 60-ampere rated overcurrent device.
What is the purpose of the main bonding jumper in a service panel?
Answer: To bond the grounded conductor (neutral) to the equipment grounding conductor and enclosure at the service
The main bonding jumper connects the grounded conductor (neutral), equipment grounding conductors, and the service enclosure together, creating the effective ground-fault current path.
Per NEC 250.64(A), what protection is required for aluminum or copper-clad aluminum grounding electrode conductors?
Answer: They must not be installed where subject to physical damage or corrosive conditions, and must not be in contact with masonry or earth
NEC 250.64(A) prohibits aluminum or copper-clad aluminum GECs from being used where in direct contact with masonry, earth, or where subject to corrosive conditions.
What is an intersystem bonding termination per NEC 250.94?
Answer: An accessible device for bonding communications systems (cable, telephone, satellite) to the building grounding electrode system
NEC 250.94 requires an intersystem bonding termination at the service or disconnect that provides accessible terminals for bonding communications systems to the grounding electrode system.
Per NEC 250.104(A), what building systems must be bonded to the electrical grounding system?
Answer: Metal water piping, metal gas piping, and other metal piping systems that may become energized
NEC 250.104(A) requires bonding of interior metal water piping, and 250.104(B) requires bonding of other metal piping systems including gas piping that may become energized.
When are supplemental ground rods required in addition to a single ground rod per NEC 250.53(A)(2)?
Answer: When the single rod does not achieve 25 ohms or less to ground
NEC 250.53(A)(2) requires a supplemental electrode when a single ground rod cannot be shown to have a resistance of 25 ohms or less to ground.