DOC · EXAM PREP
PRACTICE
WORKSHEET
Ten NEC 2023 wire fill chart practice problems with full solutions. Cross-check your answers against the live wire fill chart and the conduit fill calculator.
TOTAL
10
CORRECT
0
WRONG
0
- 01
How many 12 AWG THHN conductors fit in a 1/2-inch EMT at the NEC fill limit?
- 02
A 3/4-inch RMC carries 6 conductors of 10 AWG THWN-2. What is the fill percentage, and is it NEC-compliant?
- 03
You need to pull 4 conductors of 4/0 THHN. What is the smallest EMT trade size you may use?
- 04
What fill percentage does NEC permit for a single conductor in a conduit?
- 05
A 6-foot length of 1-inch PVC Sch 80 holds 4 conductors of 8 AWG XHHW-2. What is the fill?
- 06
Which conduit at 1-inch trade size has the largest interior area: EMT, IMC, RMC, or PVC Sch 40?
- 07
A 20-inch conduit nipple between two panelboards may be filled to what maximum percentage?
- 08
How many 250 kcmil THHN conductors fit in a 2-1/2-inch EMT?
- 09
True or false: an equipment grounding conductor (EGC) is excluded from conduit fill calculations.
- 10
You have 2 phase conductors and 1 neutral, all 6 AWG THHN, in a 3/4-inch IMC. What fill rule applies, and what is the fill percentage?
NOTE · WHY THESE PROBLEMS
Each question targets a specific NEC concept tested on the journeyman and master electrician licensing exams: Table 1 fill percentages, Table 4 conduit areas, Table 5 conductor areas, conduit-type comparison, the nipple allowance, and the EGC counting rule. Work them by hand first; verify with the calculator second.