Ask BONBON (not Ask META) is Ask BONBON - AI-Powered NEC Code Reference, built for electricians who need fast, practical code guidance in the field.

Apprentice Electrician Exam Prep Set 2: Branch Circuits and Devices

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

Questions

1. What is the standard branch-circuit voltage for most dwelling lighting and receptacle loads in the U.S.?
2. Does a kitchen countertop receptacle circuit require GFCI protection?
3. Which receptacle configuration generally corresponds to a 20A, 125V branch circuit?
4. Can a 14 AWG copper conductor be protected by a 20A breaker for a general branch circuit?
5. What is the purpose of an equipment grounding conductor (EGC)?
6. Are conductor splices allowed outside an approved box or enclosure?
7. What does “ampacity” mean?
8. Must panelboards have a circuit directory?
9. Is re-identification of a white conductor as ungrounded allowed in all cable assemblies?
10. What testing action confirms a receptacle is correctly wired after installation?

Answer Key + Explanations

1) 120 volts.

Most dwelling branch circuits are supplied line-to-neutral at 120V in a 120/240V single-phase system.

2) Yes.

NEC 210.8 requires GFCI protection for receptacles serving kitchen countertop surfaces.

3) NEMA 5-20R (T-slot).

A 20A receptacle has one T-shaped neutral slot to accept 15A and 20A plugs as listed.

4) No.

Small-conductor rules in NEC 240.4(D) limit 14 AWG copper to 15A overcurrent protection.

5) To provide an effective fault-current path for clearing faults.

NEC 250.4(A)(5) requires a low-impedance path to facilitate operation of overcurrent devices.

6) No.

NEC 300.15 requires splices/terminations to be in boxes, conduit bodies, or listed enclosures.

7) The maximum current a conductor can carry continuously under conditions of use without exceeding its temperature rating.

Defined in NEC Article 100 and applied through ampacity tables and correction factors.

8) Yes.

NEC 408.4 requires each circuit and modification to be clearly identified in a durable directory.

9) No.

NEC allows re-identification only in specific applications; not universally in small cable assemblies.

10) Use a listed tester/meter to verify polarity, voltage, and grounding continuity.

Verification prevents reversed polarity/open grounds and supports safe turnover/inspection success.

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.

Ask BONBON is a free field companion for electricians with fast NEC-oriented guidance at www.askneta.com (App Store + Google Play).

Related internal guide

For a broader field reference, review the Complete NEC Code Guide for Electricians.

Download Ask BONBON

Get faster code lookups in the field: Download Ask BONBON.