ICC G18 Residential Electrician Exam (2017 NEC) Practice Exam
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- 60 questions (same as real exam)
- 180 minute time limit
- 7 topic areas covered
- 266 questions in pool
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ICC G18 Residential Electrician (2017 NEC) Practice Exam Guide
What's on the exam
Questions per topic, out of 60This practice exam follows the official content outline for the ICC G18 Residential Electrician (2017 NEC) exam: General Knowledge, Services and Service Equipment, Feeders, Branch Circuits and Conductors, Wiring Methods and Materials, Equipment and Devices, Special Occupancies, Equipment, and Conditions.
- Free practice exam: 10 questions per attempt, retake as often as you like.
- Full practice exam: 60 questions on a 3 hours clock, a new draw from our bank every attempt.
General Knowledge 7 items
Our study plan for this topic: Electrical Theory and General Electrical Load Calculations; Code Definitions and Terms; NEC Purpose, Scope, and Code Arrangement; Equipment Approval, Listing, and Labeling Requirements; General Installation Requirements (Article 110); Working Space and Clearances Around Electrical Equipment; Conductor Materials, Sizes, and Temperature Ratings; Electrical Symbols and Wiring Diagrams.
Services and Service Equipment 13 items
Our study plan for this topic: Service Load Calculations; Service Equipment & Service Conductors; System Grounding and Bonding; Service disconnect requirements and ratings; Overhead and underground service conductor installation; Grounding electrode system and electrode types; Equipment grounding conductors — types, sizing, and identification; Bonding methods at service equipment and piping systems.
Feeders 8 items
Our study plan for this topic: Load Calculations; Equipment Grounding; Feeder conductor ampacity and minimum sizing (NEC Article 215); Overcurrent protection for feeders; Feeder neutral load calculations and permitted reductions; Ground-fault protection of equipment on feeders rated 1000A or more; Outside feeder installation requirements (clearances, wiring methods, disconnecting means); Demand factors for dwelling unit appliance loads (dryers, ranges, cooking equipment).
Branch Circuits and Conductors 15 items
Our study plan for this topic: Branch Circuit Calculations; Required Outlets & GFCI/AFCI Protection; Overcurrent Protection; Equipment Grounding; Conductors; Voltage Drop Calculations and Conductor Sizing; Conductor Ampacity Tables and Temperature Ratings; Ampacity Correction and Adjustment Factors.
Wiring Methods and Materials 8 items
Our study plan for this topic: Raceway Installations; Boxes and Enclosures; Flexible Cords and Cables; Cable Wiring Methods (NM, MC, SE, UF, and Type UF underground installations); Conductor Protection Against Physical Damage (nail plates, clearances, framing members); Underground Installation Requirements and Burial Depths; Conduit Fill Calculations and Conductor Count Limits; Conduit Bending Techniques (90° stubs, offsets, saddle bends, back-to-back).
Equipment and Devices 5 items
Our study plan for this topic: Luminaires; Receptacles, Switches and Other Devices; Appliances and Other Equipment; Luminaire location requirements (wet, damp, closets, bathtub/shower zones); Recessed luminaire installation (Type IC vs. non-IC, thermal protection, clearances); Lighting track installation and construction requirements; Low-voltage lighting system requirements (Article 411); Switch ratings, types, and installation requirements.
Special Occupancies, Equipment, and Conditions 4 items
Our study plan for this topic: Swimming Pools and Similar Installations; Low Voltage Circuits, Alarm & Similar Systems; Fire Alarm Circuit Classifications (NPLFA vs. PLFA) and Power Source Requirements; Fire Alarm Cable Types and Installation by Location (FPLP, FPLR, FPL, NPLFP, NPLFR, NPLF); Class 1, Class 2, and Class 3 Circuit Definitions and Power Source Limitations; Separation and Mixing Rules for Class 2/3 Circuits with Other Circuit Types; Communications Circuit Wiring Methods, Cable Types (CMP, CMR, CM, CMX), and Installation by Location; Primary Protector Requirements and Grounding/Bonding for Communications Systems.
Sample 1 — Branch Circuits and Conductors
Question: A single-family dwelling with a 120/240-volt, single-phase service has a calculated load of 154 amps. Using 75°C rated copper THWN-2 conductors, what is the minimum service conductor size?
- A. 1 AWG
- B. 1/0 AWG
- C. 2/0 AWG
- D. 3/0 AWG
Correct Answer: B
Step 1: A 154 A calculated load needs a service rated at least 154 A; the next standard rating is 175 A (240.6(A)).
Step 2: For a one-family dwelling supplied by a 120/240-volt, single-phase service, the NEC permits service conductors with an ampacity of not less than 83% of the service rating (310.12(A); 310.15(B)(7) in the 2017 NEC): 175 A × 0.83 = 145.25 A.
Step 3: In the 75°C copper column of Table 310.16, 1 AWG = 130 A (too small) and 1/0 AWG = 150 A, so 1/0 AWG copper is the minimum. Table 310.12(A) likewise lists 1/0 AWG copper for a 175 A dwelling service.
2/0 AWG (175 A) is what you get by sizing for the full 154 A with Table 310.16 alone, without the dwelling allowance.
Reference: NEC 2023 Section 310.12(A) and Table 310.12(A) (2017 NEC: 310.15(B)(7)); Table 310.16; 240.6(A)
Sample 2 — Services and Service Equipment
Question: When the grounding electrode conductor is connected solely to a rod, pipe, or plate electrode and does not extend to other electrode types requiring a larger conductor, what is the maximum required size of a copper grounding electrode conductor?
- A. 8 AWG copper
- B. 6 AWG copper
- C. 4 AWG copper
- D. 2 AWG copper
Correct Answer: B
Per NEC 250.66(A), where the grounding electrode conductor is connected to a single or multiple rod, pipe, or plate electrode(s) and does not extend to other types of electrodes requiring a larger conductor, it shall not be required to be larger than 6 AWG copper wire.
Reference: NEC 2017 Section 250.66(A)
Sample 3 — Feeders
Question: A 400 A service uses 600 kcmil copper service conductors. What is the minimum size of a copper grounding electrode conductor that runs only to a concrete-encased electrode?
- A. 2 AWG
- B. 4 AWG
- C. 3/0 AWG
- D. 1/0 AWG
Correct Answer: B
Table 250.66 would require a 1/0 AWG copper grounding electrode conductor for 600 kcmil copper service conductors, but 250.66(B) says a grounding electrode conductor (or bonding jumper) that runs only to a concrete-encased electrode is not required to be larger than 4 AWG copper. So the minimum size required here is 4 AWG copper.
Reference: NEC 2017 Section 250.66(B), Table 250.66
- Your results break the score down by outline topic.
- The real exam's passing score: 70% correct.
- Keep practicing until you pass consistently, not just once.
- Answer what you know first and bookmark the rest. Our practice exams let you bookmark and come back.
- Work your bookmarks on the second pass.
- Real exam pace: about 3 minutes per question.
- After each attempt, look up every miss in your book.
| Questions | 60 questions |
| Time limit | 3 hours |
| Passing score | 70% correct |
| Books in the exam room | Open book |
| Exam fee | $120 |
- Results for examinations taken electronically are available immediately after the examination is completed.
- You must wait 10 days before retaking a failed exam.
Source: National Contractor/Trades Examination Information Bulletin, PUBLISHED June 30, 2026; ICC Exam Catalog, checked September 27, 2026. Check the bulletin before test day: fees and rules can change.