Journeyman Electrician’s Exam Journeyman Electrician's Grounding and Bonding 2 — Questions and Answers
Question 1: What is the minimum size equipment grounding conductor required for a 60-ampere circuit protected by a 60A breaker per NEC Table 250.122?
- 10 AWG copper (Correct answer)
- 8 AWG copper
- 6 AWG copper
- 4 AWG copper
Correct answer: 10 AWG copper
Per NEC Table 250.122, a 60A overcurrent device requires a minimum 10 AWG copper equipment grounding conductor.
Question 2: Which NEC article primarily covers grounding and bonding requirements?
- Article 230
- Article 240
- Article 250 (Correct answer)
- Article 310
Correct answer: Article 250
NEC Article 250 covers all grounding and bonding requirements for electrical systems.
Question 3: A grounding electrode conductor is used to connect the grounded conductor to the:
- Equipment grounding conductor at the load
- Grounding electrode system (Correct answer)
- Neutral bar at a subpanel
- Service entrance conduit
Correct answer: Grounding electrode system
The grounding electrode conductor connects the grounded (neutral) conductor or equipment to the grounding electrode system.
Question 4: What is the purpose of bonding in an electrical system?
- To reduce voltage drop on branch circuits
- To establish electrical continuity between conductive parts (Correct answer)
- To increase the ampacity of conductors
- To isolate metal parts from the ground
Correct answer: To establish electrical continuity between conductive parts
Bonding establishes electrical continuity and conductivity between conductive parts to ensure a low-impedance path for fault current.
Question 5: When installing a grounding electrode conductor in a metal raceway, what additional bonding requirement applies?
- The raceway must be plastic-lined
- Both ends of the raceway must be bonded to the conductor (Correct answer)
- The raceway must be at least 1 inch trade size
- A separate insulated conductor must run alongside
Correct answer: Both ends of the raceway must be bonded to the conductor
Per NEC 250.64(E), metal raceways enclosing a grounding electrode conductor must be bonded at both ends to the conductor.
Question 6: Which of the following may NOT be used as a grounding electrode per NEC 250.52?
- Concrete-encased electrode (Ufer)
- Metal underground water pipe
- Metal underground gas piping system (Correct answer)
- Ground ring
Correct answer: Metal underground gas piping system
Per NEC 250.52(B)(1), underground gas piping systems are specifically prohibited as grounding electrodes.
Question 7: What is the maximum resistance allowed for a single-rod grounding electrode before a supplemental electrode is required per NEC 250.56?
- 5 ohms
- 15 ohms
- 25 ohms (Correct answer)
- 50 ohms
Correct answer: 25 ohms
Per NEC 250.56, if a single rod, pipe, or plate electrode has a resistance exceeding 25 ohms, a supplemental electrode must be added.
Journeyman Electrician’s Exam Journeyman Electrician's Grounding and Bonding 2
What is the minimum size equipment grounding conductor required for a 60-ampere circuit protected by a 60A breaker per NEC Table 250.122?