Mike Holt accuracy test (review 4)

What the test looked like

Ran Mike Holt's free NEC practice questions through Ask BONBON over two weeks. 60 questions total, pulled from his 2023 Journeyman and Master prep sets. Covered Articles 210, 215, 220, 240, 250, 310, 408, and the usual suspects in Chapter 3. Scored each answer against Mike's published key.

Goal was simple. Does the app give the same answer a working electrician would get if he read the code book cover to cover. Not marketing speak. Actual citations, actual numbers, actual conductor sizing.

I was not gentle. Threw in the trick questions Mike loves, the ones where 240.4(D) small conductor rules override the 310.16 ampacity table. Those are where most apps fall apart.

The scoreboard

Ask BONBON hit 57 out of 60. That is 95 percent. The three misses were not wrong answers exactly, they were incomplete. Missed a secondary reference, gave the right ampacity but forgot to mention the terminal temperature limit under 110.14(C).

For comparison, I ran the same 60 through two other code apps. One scored 71 percent. The other pulled 83 percent but kept citing the 2017 NEC when I asked about 2023 rules. That is a deal breaker on any job inspected under current adoption.

• Ask BONBON: 57/60 (95%)
• Competitor A: 50/60 (83%), wrong code cycle
• Competitor B: 43/60 (71%)
• Mike Holt's answer key: the benchmark

Where it nailed the details

Ampacity correction and adjustment. This is where apprentices lose points and where most apps either skip the math or dump a wall of text. Asked about four current-carrying conductors in a 40C ambient, THHN copper. Got back the 0.88 adjustment from 310.15(C)(1), the 0.91 correction from 310.15(B)(1)(1), and the final ampacity with both applied. Cited each table by number.

GFCI and AFCI rules. These change every cycle and the 2023 expansions caught a lot of guys off guard. Asked about a basement receptacle outside the dwelling definition, got the correct 210.8(B) commercial answer, not the 210.8(A) residential one. That distinction matters when you are wiring a mixed use building.

Tip from the field: if an app gives you a code section without a subsection letter, do not trust it. 210.8 alone is useless. You need 210.8(A)(7) or 210.8(B)(6) to answer the actual question.

Where it stumbled

Grounding electrode conductor sizing on a parallel service. Mike's question pulled from 250.66 and Table 250.102(C)(1). App gave the right GEC size but skipped the supply side bonding jumper calc that was the second half of the question. Partial credit in a classroom, zero on the exam.

Motor feeder calculations with multiple motors. Got the largest motor 125 percent rule from 430.24 correct. Missed that the question was asking about the overcurrent device, not the conductor, so it pulled from 430.22 instead of 430.62. Close but not right.

Transformer secondary conductor protection under 240.21(C). Gave the 10 foot tap rule answer when the question was set up for the 25 foot rule. Read the question wrong, basically. A journeyman would catch it on reread.

What this means on the job

95 percent on Mike Holt is better than most first year apprentices score and about even with a sharp journeyman prepping for the master exam. For code reference on an active job site, that accuracy level means you can trust the answer for rough-in decisions and verify critical pulls against the book.

Do not use any app, including this one, as your only source for a gear submittal or a service calculation that an inspector will stamp. Use it to get 90 percent of the way there fast, then open the book for the final verification.

1. Quick lookups during rough-in: trust the app
2. Apprentice training and exam prep: trust but verify with Mike's material
3. Submittals, permit drawings, inspection prep: open the book
4. Anything involving POCO coordination: call the engineer

Mike Holt himself

Worth saying. Mike's material is the gold standard because he writes questions the way inspectors ask them, not the way textbook authors do. If an app can pass his tests at 90 plus percent, it understands the code the way the field understands it. That is the real bar.

His free practice questions are at mikeholt.com and they update every code cycle. Run any code app you are considering buying through at least 50 of them before you pay for a subscription. If it cannot crack 85 percent, it is not ready for your tool belt.

Tip from the field: save Mike's questions in a folder on your phone. When an apprentice asks you a code question on the job, pull a related one and quiz him back. Teaches him to read the code, not just ask for the answer.

The verdict

Ask BONBON passed the Mike Holt test. Not perfectly, but well enough that I kept it on my phone after the review period ended. The 2023 code accuracy alone puts it ahead of every other app I tested. The three misses were teaching moments, not dealbreakers.

If you are running jobs under the 2023 NEC and you want a reference that gives you the right subsection letter without scrolling through ads, this one earns its spot. If you are still on 2020 adoption, check your state before buying any digital reference. The code cycle matters more than the app.