ElectricalToolbox

Journeyman Electrician Practice Test

Twenty exam-style questions on the National Electrical Code (NEC), graded instantly with the arithmetic worked out and the governing table or article cited on every answer.

Question 1

Question 1 of 20 · Voltage drop

A 20 A load is served by a 120 V, single-phase branch circuit run 100 ft one way in 12 AWG copper. Using VD = (2 × K × I × L) / cmil with K = 12.9 Ω·cmil/ft, the approximate voltage drop is:

Question 2

Question 2 of 20 · Ampacity adjustment

Eight current-carrying 12 AWG THHN copper conductors share one EMT raceway at 30 °C ambient. The adjusted ampacity of each conductor is:

Question 3

Question 3 of 20 · Conduit fill

The maximum number of 12 AWG THHN conductors permitted in 3/4-in. EMT is:

Question 4

Question 4 of 20 · Conduit fill

When a conduit or tubing nipple longer than 24 in. contains exactly two conductors, the maximum allowable fill is:

Question 5

Question 5 of 20 · Conductor properties

Per NEC Chapter 9, Table 8, the circular-mil area of 12 AWG is:

Question 6

Question 6 of 20 · Overcurrent protection

Which of the following is NOT a standard ampere rating for fuses and inverse-time circuit breakers?

Question 7

Question 7 of 20 · Grounding and bonding

The minimum size copper equipment grounding conductor for a circuit protected by a 60 A overcurrent device is:

Question 8

Question 8 of 20 · Grounding and bonding

A service has 2/0 AWG copper service-entrance conductors. The minimum copper grounding electrode conductor (to a metal water pipe electrode) is:

Question 9

Question 9 of 20 · Branch circuits

A branch circuit supplies a 40 A continuous load (3 hours or more). The minimum overcurrent device rating is:

Question 10

Question 10 of 20 · Dwelling requirements

In dwelling habitable rooms, wall receptacles must be spaced so that no point along the floor line of any wall space is more than ______ from a receptacle outlet.

Question 11

Question 11 of 20 · Dwelling requirements

The minimum number and rating of small-appliance branch circuits required to serve dwelling kitchen countertop receptacles is:

Question 12

Question 12 of 20 · General requirements

For equipment operating at 120/240 V and likely to require examination while energized, the minimum depth of clear working space in front of the equipment is:

Question 13

Question 13 of 20 · Boxes and enclosures

For box-fill calculations, each 12 AWG conductor counts as:

Question 14

Question 14 of 20 · Ampacity correction

A 90 °C-insulated conductor (THHN) is installed where the ambient temperature is 40 °C. The ambient correction factor applied to its Table 310.16 ampacity is:

Question 15

Question 15 of 20 · Wiring methods

The general minimum burial depth for direct-buried UF cable (not under a building, roadway, or covered by other Table 300.5 exceptions) is:

Question 16

Question 16 of 20 · Definitions and identification

An insulated grounded conductor of 6 AWG or smaller must be identified by:

Question 17

Question 17 of 20 · Ampacity

Per NEC Table 310.16, the allowable ampacity of 6 AWG copper THWN (75 °C) with not more than three current-carrying conductors is:

Question 18

Question 18 of 20 · Voltage drop

The NEC informational notes recommend limiting branch-circuit voltage drop to ______ and the combined feeder-plus-branch drop to ______ for reasonable efficiency of operation.

Question 19

Question 19 of 20 · Overcurrent protection

Unless a specific exception applies, the maximum overcurrent protection for 14 AWG copper conductors is:

Question 20

Question 20 of 20 · Services

The service disconnecting means for a one-family dwelling must have a rating of not less than:

How to use this practice test

  1. Work through all 20 questions. Treat it as closed-book on the rule questions and open-book on the calculations, the way exam time pressure actually plays out.
  2. Grade the test. Each question reveals the worked answer and its NEC reference.
  3. For any miss, look up the cited table or article and re-derive the answer yourself. Navigating to the reference fast is most of the exam skill.
  4. Use the site's calculators (linked below) to check your own re-derivations.

NEC reference

Questions reference the NEC 2020 edition. Answers use values that are identical in the 2017, 2020, and 2023 editions unless the explanation says otherwise. Section numbering follows the 2020/2023 editions; in NEC 2017, Table 310.16 was 310.15(B)(16), Table 310.15(B)(1) was 310.15(B)(2)(a), and Table 310.15(C)(1) was 310.15(B)(3)(a). Every calculated answer in this set is verified against the same National Electrical Code table data that powers this site's calculators. Tables 310.16, 310.15(B)(1), 310.15(C)(1), 250.66, 250.122, 314.16(B), and Chapter 9 Tables 1, 4, 5, and 8.

Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.

Continuing education and exam prep

Many licensing jurisdictions require continuing education hours each renewal cycle. Mike Holt's continuing education courses are organized by state, and his exam preparation programs cover journeyman and master license exams. Confirm any course is approved for your license and jurisdiction before enrolling.

This page contains affiliate links. ElectricalToolbox may earn a commission when you sign up or buy through them, at no additional cost to you.

Check your work with the calculators

Working in a specific state? Confirm which NEC edition your state enforces. Your exam references the adopted edition.