Which code edition is the exam on?
The 2023 NEC — the plain national edition, with no California amendments.
It is supplied inside the testing software along with NFPA 70E 2024 and the Cal/OSHA construction pocket guide, all three searchable, and you may not bring your own copies. What that actually means for you is a separate question, and a more important one.
The warning you have probably read is wrong
California adopted the 2025 California Electrical Code for field work from 1 January 2026. Nearly every prep site will tell you that studying from it means learning section numbers the exam does not use.
That is not true of the 2025 CEC
The 2025 California Electrical Code is the 2023 NEC, with California's amendments folded into it. Same articles, same sections, same tables, same numbers. Open it to 310.16 and you are looking at the table the exam is looking at. The numbering objection is simply a mistake, repeated.
The real trap is the opposite one
Because the numbering matches perfectly, there is nothing to warn you when you are reading a California amendment. It sits in the same section, in the same typeface, under the same number as the national rule it modifies — and the exam does not test it.
A book with obviously wrong section numbers is a problem you notice on the first lookup. A book whose numbers are right and whose text is occasionally different is a problem you never notice at all — until an answer you were certain of is marked wrong, and you have no idea which of the rules you learned was the state's rather than the country's. That is a worse failure mode than the one everyone warns about, and it is the one that is real.
Editions that genuinely do not line up
A 2017 or 2020 book
These are the ones that will genuinely mislead you, and most second-hand prep material is built on them. Article 220 was reorganised for 2023, so remembered section numbers there will not find what you expect. Navigate Article 220 by its part headings rather than by memory.
A 2026 NEC
The next national edition is the one that renumbers. If you are buying new and the shop offers you the newest book on the shelf, that is the wrong instinct here: newer is further from the edition on the screen, not closer to it.
So what should you actually read
The 2023 NEC, and you can read it free and legally without buying anything — NFPA publishes free online access to its current standards, which covers both the NEC and 70E. If you want a copy on paper, or you are buying one for the truck as well as for the test, what to buy and what to skip goes through the editions and the bindings, and lists the free sources before the paid ones.
Buy the 2025 California code because you are wiring in California. Do not buy it because you are sitting the test.
Next
- How the NEC is organised — the nine chapters and what each one owns.
- What "open book" really means here — and why it makes the exam harder.
- Ten free practice questions — every answer cites its section.
Written by Chris Furman · last reviewed 18 September 2026
I built Electrician Cards after watching a friend prepare for this exam and discovering how much of the published advice is written for a closed-book test. I am not an electrician — everything here is researched from the candidate bulletin, the 2023 NEC's own structure, and the official content outline, and it is checked against them again whenever it changes. Always verify against the code book itself.