TL;DR
Master grounding and bonding requirements per the National Electrical Code. Proper grounding prevents electrical shock and fire hazards and is one of the most tested topics on electrician exams.
Free Grounding Electrode System Practice Questions
Journeyman Electrician License Exam · Grounding & Bonding
This module covers Grounding Electrode System as part of the Grounding & Bonding section, testing your understanding of core concepts and their practical application.
| Exam | Journeyman Electrician License Exam |
| Pass Rate | 55% |
| Duration | 240 minutes |
| Module | Grounding Electrode System |
Why Grounding Electrode System matters
Grounding Electrode System is one of the most tested NEC topics because improper grounding and protection cause electrical fires and fatalities.
Sample Practice Questions (5)
1. Per NEC 250.52(A)(1), when a metal underground water pipe is used as a grounding electrode, it shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(8). Why is this supplemental electrode required?
- Because water pipes always have high resistance
- Because portions of the water pipe may be replaced with nonmetallic pipe, potentially losing the ground path
- Because the water utility requires it
- Only required in commercial occupancies
2. Per NEC 250.66(B), where a concrete-encased grounding electrode as described in 250.52(A)(3) is used, the grounding electrode conductor (GEC) need not be larger than:
- 8 AWG copper
- 6 AWG copper
- 4 AWG copper
- 2 AWG copper
3. Per NEC 250.52(A)(3), a concrete-encased electrode can also use steel reinforcing bars (rebar). The minimum diameter of the rebar shall be:
- 3/8 inch (No. 3 rebar)
- 1/2 inch (No. 4 rebar)
- 5/8 inch (No. 5 rebar)
- 3/4 inch (No. 6 rebar)
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Start practicing free →4. Per NEC 250.64(B), a grounding electrode conductor (GEC) shall be permitted to be run along the surface of the building construction. It shall be securely fastened and protected from physical damage. Where exposed to physical damage, the GEC shall be protected in:
- Rigid metal conduit (RMC), intermediate metal conduit (IMC), rigid PVC conduit, electrical metallic tubing (EMT), or cable armor
- Only rigid metal conduit (RMC)
- Any wiring method listed in Chapter 3
- Rigid metal conduit (RMC), intermediate metal conduit (IMC), rigid PVC conduit (Schedule 80), electrical metallic tubing (EMT), reinforced thermosetting resin conduit (RTRC), or other approved means
5. Per NEC 250.52(A)(2), the metal frame of a building or structure qualifies as a grounding electrode when:
- It is connected to a panelboard
- It is effectively grounded by any one of the methods specified in 250.52(A)(2)
- It is painted to prevent corrosion
- It is located in a commercial building only
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