Journeyman Electrician’s Exam Journeyman Electrician's Grounding and Bonding 5 — Questions and Answers
Question 1: Metal gas piping in a building must be bonded per NEC 250.104(B) to which of the following?
- The nearest grounding rod
- The equipment grounding conductor of the circuit likely to energize the piping (Correct answer)
- The cold water pipe at the water heater
- The main service panel neutral bar only
Correct answer: The equipment grounding conductor of the circuit likely to energize the piping
Per NEC 250.104(B), interior metal gas piping must be bonded to the equipment grounding conductor of the circuit that is most likely to energize the piping.
Question 2: What is the maximum size copper equipment grounding conductor that may be bare (uninsulated) when installed in a raceway?
- Any size may be bare in a raceway (Correct answer)
- 6 AWG and smaller must be insulated
- No restriction — bare is always allowed
- Only 4 AWG and larger may be bare
Correct answer: Any size may be bare in a raceway
Per NEC 250.119, equipment grounding conductors of any size may be bare, covered, or insulated when installed in a raceway.
Question 3: A patient care area in a hospital requires what type of grounding system per NEC 517?
- Standard equipment grounding with GFCI outlets
- An isolated (ungrounded) power system with a line isolation monitor (Correct answer)
- Double-insulated equipment only — no grounding required
- A redundant grounding electrode system
Correct answer: An isolated (ungrounded) power system with a line isolation monitor
NEC Article 517 requires critical care areas to use an isolated (ungrounded) power system with a line isolation monitor to allow the circuit to continue operating during a first fault.
Question 4: Which of the following correctly describes the difference between grounding and bonding?
- Grounding connects equipment to earth; bonding connects conductive parts to each other (Correct answer)
- Bonding connects equipment to earth; grounding connects conductive parts to each other
- They are interchangeable terms with no distinction
- Grounding is for AC systems; bonding is for DC systems only
Correct answer: Grounding connects equipment to earth; bonding connects conductive parts to each other
Grounding connects the electrical system to earth (the grounding electrode system), while bonding connects conductive parts together to ensure electrical continuity.
Question 5: When a panelboard is used as service equipment, the equipment grounding terminal bar must be bonded to the enclosure using a:
- Equipment bonding jumper
- Grounding electrode conductor
- Main bonding jumper (Correct answer)
- System bonding jumper
Correct answer: Main bonding jumper
At service equipment, the main bonding jumper connects the neutral (grounded conductor) terminal bar to the equipment enclosure and the EGC terminal bar.
Question 6: What NEC rule applies to the grounding electrode conductor at the point it connects to a water pipe electrode?
- The connection must be accessible and made with a listed clamp (Correct answer)
- The connection may be made with any listed wire connector
- Soldering is the preferred connection method
- The conductor must be spliced at least once before the connection
Correct answer: The connection must be accessible and made with a listed clamp
Per NEC 250.70, connections to grounding electrodes must be made with listed fittings, and connections to pipe electrodes must be accessible and made with listed clamps.
Question 7: An equipment grounding conductor run with circuit conductors in a conduit system primarily protects against:
- Voltage drop under heavy load
- Electric shock from a ground fault on equipment (Correct answer)
- Inductive reactance in the conductors
- Overheating of the grounded conductor
Correct answer: Electric shock from a ground fault on equipment
The EGC provides a low-impedance path for fault current to return to the source, causing the overcurrent device to open and protect against electric shock from faulted equipment.
Journeyman Electrician’s Exam Journeyman Electrician's Grounding and Bonding 5
Metal gas piping in a building must be bonded per NEC 250.104(B) to which of the following?