Washington Electrician Calculations Practice (01 Exam)
Washington splits the exam into NEC and Theory plus Laws and Rules. Calculations live mostly on the NEC side, but you still need to pass each section at 70%, so math practice cannot crowd out the law section.
Last reviewed June 2026
NEC section
60 q
Law section
17 q
To pass
70% each
Exam code
2020 NEC
Calculation work belongs to the NEC section
Do the math against the 2020 NEC, then keep a separate law block for RCW and WAC. Washington candidates lose time when those two study lanes blur together.
Box fill
Count the box allowances before selecting the volume. Do not let multiple grounds trick you into multiple counts.
Chapter 9Conduit fill
Practice the 53, 31, and 40 percent rules, then confirm raceway and conductor area from the right tables.
Informational notesVoltage drop
Pick one-phase or three-phase first. Then verify length, conductor material, and circular mil area.
250.66 and 250.122Grounding and bonding sizing
The GEC table and EGC table do different jobs. The wrong table can produce a believable answer.
Article 430Motor calculations
Separate conductor, overcurrent, and overload rules. Washington still grades the NEC part by exact rule choice.
A Washington calculation practice block
Run the NEC block and law block separately. You need both, but the calculation repair should stay on the 2020 NEC side.
- Set the section: Ask whether the question is NEC and Theory or Washington Laws and Rules. Calculations go in the NEC lane.
- Use the 2020 NEC: The exam uses the 2020 NEC even though the field code has moved forward. Practice with the exam edition.
- Write the table path: For every miss, write the article and table path you should have used before writing the corrected math.
- Protect law study time: Do not let calculation work consume the whole week. The 17-question law section can fail you on its own.
Washington calculation misses to watch
- Studying 2023 NEC material for an exam that still cites the 2020 NEC.
- Combining section scores in practice when Washington scores each section separately.
- Ignoring RCW and WAC study because NEC calculations feel more technical.
- Using a single national practice bank that never asks Washington law questions.
Let the diagnostic separate NEC from law
If your misses are law questions, another conduit-fill set is not the fix. If your misses are table lookup and math setup, the NEC calculation block gets the next night.
Where the facts come from
Find which Washington section is costing you
Take the free Washington diagnostic and see whether the next repair is NEC calculations, codebook lookup, or Laws and Rules.