Journeyman Electricianâs Exam Journeyman Electrician's Grounding and Bonding 3 â Questions and Answers
Question 1: At a separately derived system, the grounding electrode conductor must be connected to the:
- First overcurrent device downstream
- Neutral point of the derived system (Correct answer)
- Equipment grounding bus at the first panel
- Nearest metal water pipe
Correct answer: Neutral point of the derived system
Per NEC 250.30(A), the grounding electrode conductor for a separately derived system connects to the neutral (grounded) point of that system.
Question 2: A main bonding jumper is required at the:
- Load side of every subpanel
- Service entrance equipment only (Correct answer)
- Each branch circuit panel
- Every splice point in the neutral conductor
Correct answer: Service entrance equipment only
The main bonding jumper connects the grounded conductor to the equipment grounding conductor and is required only at the service entrance equipment.
Question 3: Which conductor connects metal parts of equipment to the equipment grounding conductor or grounding electrode?
- Grounding electrode conductor
- Main bonding jumper
- Equipment bonding jumper (Correct answer)
- System bonding jumper
Correct answer: Equipment bonding jumper
An equipment bonding jumper connects metal parts of equipment to ensure they are at ground potential and part of the fault current path.
Question 4: For a 200A service, what is the minimum size copper grounding electrode conductor required per NEC Table 250.66?
- 6 AWG
- 4 AWG (Correct answer)
- 2 AWG
- 1/0 AWG
Correct answer: 4 AWG
Per NEC Table 250.66, for service entrance conductors of 3/0 AWG copper (typical for 200A), a 4 AWG copper GEC is required.
Question 5: What is the minimum burial depth for a ground rod electrode per NEC 250.53(G)?
- 4 feet
- 6 feet
- 8 feet (Correct answer)
- 10 feet
Correct answer: 8 feet
Per NEC 250.53(G), rod and pipe electrodes must be installed so at least 8 feet of length is in contact with the soil.
Question 6: In a multi-wire branch circuit, which of the following best describes the neutral conductor's role with respect to grounding?
- It serves as both the grounded conductor and an equipment grounding conductor
- It is the grounded conductor and must not be used as an EGC (Correct answer)
- It must be bonded to the equipment grounding conductor at each outlet
- It may be disconnected without affecting equipment grounding
Correct answer: It is the grounded conductor and must not be used as an EGC
The neutral is the grounded conductor and carries return current; per NEC 250.142(B), it cannot serve as an EGC downstream of the service.
Question 7: Bonding of metal water piping systems within a building is required by NEC 250.104 to ensure:
- Lower water pressure in the pipes
- The piping is part of the effective ground-fault path (Correct answer)
- All plumbing is energized at line voltage
- Water meters are not damaged by fault current
Correct answer: The piping is part of the effective ground-fault path
NEC 250.104 requires interior metal water piping to be bonded so it is part of the effective ground-fault current path, reducing shock hazard.
Journeyman Electricianâs Exam Journeyman Electrician's Grounding and Bonding 3
At a separately derived system, the grounding electrode conductor must be connected to the: