Question 1: Grounding in electrical system limit the high current and thus reduces the damage.
- True
- False
NEC Reference: NEC 250.2
NEC CODE
NEC 2023
Grounding and Bonding (NEC 250)
Free online test on Grounding and bonding ( National Electrical Code - 250)
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The National Electrical Code (NFPA 70) is the benchmark standard for safe electrical installation in the US. It is updated every 3 years by the NFPA.
Study the edition adopted by your state. As of 2025, most states use the 2020 or 2023 NEC. These tests are written to the 2023 edition.
The most tested articles are 100 (Definitions), 200–250 (Wiring & Grounding), 300–314 (Wiring Methods), 400–411 (Conductors), 430 (Motors), and 700–701 (Emergency Systems).
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Student Reviews 4.0 / 5 · 2 reviews
R
Rhonda F.
Grounding and bonding is honestly the hardest section of the NEC for most people and this quiz does a good job covering it. I had to look up a few things in the code book after but that's kind of the point. Good questions.
R
Rhonda F.
Grounding and bonding is honestly the hardest section of the NEC for most people and this quiz does a good job covering it. I had to look up a few things in the code book after but that's kind of the point. Good questions.
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Grounding and Bonding (NEC 250) — Question List
Question 2: The secondary systems of lighting circuits shall not be grounded.
- True
- False
NEC Reference: NEC 411.5
Question 3: An additional grounding connection shall me made to the transformer supplying the feeder service in the building.
- True
- False
NEC Reference: NEC 250.24(2)
Question 4: The grounded conductor ampacity of a delta connected 3-phase 3-wire system must be less the rating of ..................................
- ungrounded conductor
- secondary conductor
- neutral conductor
NEC Reference: NEC 250.24(c)(3)
Question 5: In a single raceway the size of the grounded conductor shall not be larger than the ungrounded conductor in the raceway.
- True
- False
NEC Reference: NEC 250.24(c)(1)
Question 6: In a single phase three wire electrical system, the middle conductor of a 3-wire should be which of the following?
- Grounded
- ungrounded
- hot conductor
NEC Reference: NEC 250.26
Question 7: Mostly grounding wires are identified which of the following color?
- white or natural grey
- red
- green
- grey
Question 8: The grounded wire shall never be interrupted by a circuit breaker or a fuse.
- True
- False
Question 9: In a single phase electrical system the size of the largest ungrounded service entrance aluminum conductor is 1/0 AWG, which of the following is the size of the grounding conductor?
- Aluminum No 6 AWG
- Aluminum No 4 AWG
- Copper No 2 AWG
- Copper No 6 AWG
NEC Reference: NEC 250.66
Question 10: The lighting system protection ground terminals shall be bonded to which of the following grounding electrode system?
- Building or structure
- Distributed panel board
- service entrance
NEC Reference: NEC 250.106
Grounding and bonding is honestly the hardest section of the NEC for most people and this quiz does a good job covering it. I had to look up a few things in the code book after but that's kind of the point. Good questions.
Grounding and bonding is honestly the hardest section of the NEC for most people and this quiz does a good job covering it. I had to look up a few things in the code book after but that's kind of the point. Good questions.