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Apprentice Electrician Exam Prep Set 1: NEC Core Fundamentals

Use this set as a timed drill: answer first, then check the key and explanation.

Questions

1. What is the minimum working clearance depth in front of 0-150V to ground equipment where conditions are normal?
2. Are GFCI receptacles required in residential garages?
3. What color is typically used to identify grounded (neutral) conductors in premises wiring?
4. What is the minimum cover depth for direct-buried residential branch-circuit conductors (120V, GFCI protected, 20A or less) under a 2-inch concrete slab?
5. Can NM cable be installed in wet locations?
6. Which NEC article covers overcurrent protection devices in general?
7. What does AFCI stand for?
8. Is box fill based on conductor count and conductor size?
9. What NEC article covers grounding and bonding?
10. What is the first safety step before working inside a panelboard?

Answer Key + Explanations

1) 3 feet (36 inches).

NEC 110.26(A)(1) Table requires 3 ft in Condition 1 for 0-150V to ground.

2) Yes.

NEC 210.8(A) includes garages, so 125V/250V receptacles in those areas need GFCI protection as applicable.

3) White or gray.

NEC 200.6 identifies grounded conductors by continuous white/gray outer finish or marking.

4) 12 inches.

NEC 300.5 and its notes/tables provide reduced cover in specific residential/GFCI conditions.

5) No.

NEC 334 limits NM cable to normally dry locations; wet or damp areas require listed wet-location wiring methods.

6) Article 240.

Article 240 sets the rules for overcurrent protection including sizing and protection of conductors.

7) Arc-Fault Circuit-Interrupter.

AFCI devices detect arcing characteristics that can lead to fire hazards, addressed in NEC 210.12.

8) Yes.

NEC 314.16 calculates required box volume from conductor equivalents and device allowances.

9) Article 250.

Grounding electrodes, bonding jumpers, equipment grounding conductors, and related rules are in Article 250.

10) Establish an electrically safe work condition (de-energize, verify absence of voltage, lockout/tagout).

NFPA 70E and OSHA expectations require hazard elimination and verification before exposure to energized parts.

References

• NFPA 70, National Electrical Code (NEC), current adopted edition in your jurisdiction.
• NFPA 70E, Standard for Electrical Safety in the Workplace.
• OSHA 29 CFR 1910 Subpart S and 1926 Subpart K (as applicable).
• Local AHJ amendments and utility service requirements.

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Related internal guide

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