Mike Holt accuracy test (review 7)

Why test Mike Holt at all

Mike Holt is the gold standard for NEC training. His books, videos, and illustrated guides have taught more electricians than any other source in the trade. So when someone asks why I spent a week comparing Ask BONBON to Mike Holt's material, the answer is simple. If an app claims to help working electricians with code questions, it has to hold up against the best reference material out there.

This is not a hit piece. I use Mike Holt content and recommend it. But a 600 page book lives in the truck, not in your hand at the top of a ladder. The test is whether a phone app can deliver the same accuracy when you need an answer in 15 seconds.

The test setup

I pulled 40 questions from three sources. Real questions I heard on jobs over the last month, the Mike Holt forum code discussion threads, and a handful of tricky calls from practice exam prep material. The topics covered grounding and bonding, GFCI and AFCI requirements, conductor sizing and ampacity, box fill, motor circuits, and a few wire pulling edge cases.

For each question I checked the answer against the 2023 NEC directly, then graded both Mike Holt material and Ask BONBON on whether they got it right, cited the correct article, and explained the reasoning in a way a working electrician could actually use on the job.

• Grounding and bonding: 8 questions (NEC Article 250)
• GFCI and AFCI: 7 questions (NEC 210.8 and 210.12)
• Conductor ampacity: 8 questions (NEC 310.16 and adjustment factors)
• Box fill: 5 questions (NEC 314.16)
• Motor circuits: 6 questions (NEC Article 430)
• Wire pulling and raceway fill: 6 questions (NEC Chapter 9 tables)

Where Mike Holt wins

On deep explanation, Mike Holt is still unbeaten. The illustrated guides break down the logic behind a code section with diagrams that make a concept stick. If you are studying for a journeyman or master exam, or if you are trying to understand why 250.122 sizes EGCs the way it does, you want that material.

The forum community is another strength. Post a weird question about a parallel service with a shared neutral and you will get three veteran electricians and an inspector weighing in within a few hours. No app replaces that kind of peer review.

Field tip: keep a Mike Holt Understanding the NEC Volume 1 in the truck for the grounding and bonding chapters. When a job hits a gray area, that book plus a call to the AHJ beats any quick reference.

Where Ask BONBON held up

On the 40 question test, Ask BONBON matched the correct NEC answer on 38 of them. The two misses were both on motor circuit sizing where the question was ambiguous about whether the load was continuous. Mike Holt printed material got 40 of 40 because a book cannot be ambiguous about what question it is answering, but the forum threads I sampled had a similar hit rate of around 36 of 40 once you account for the back and forth between commenters.

Where the app wins is speed. A question about GFCI requirements for a garage receptacle serving a dedicated freezer took 12 seconds to answer with the relevant NEC 210.8(A)(2) citation and the 2023 code change that removed the dedicated appliance exception. The same answer took me about 4 minutes to find in a printed index, and 20 minutes of scrolling on the forum.

The honest comparison

Different tools for different jobs. Mike Holt is a teacher. The app is a lookup. Trying to use either one for the wrong purpose is where people get frustrated.

1. Studying for an exam or learning the code deeply: Mike Holt, every time.
2. Standing in an attic at 2pm and need to know if a junction box needs to be accessible: app.
3. Arguing with an inspector about a gray area: both, plus the AHJ phone number.
4. Training an apprentice: Mike Holt videos and illustrated guides.
5. Estimating a job and need quick box fill or conduit fill numbers: app.

The mistake is thinking one replaces the other. I have Mike Holt material in my library and the app on my phone. They serve different moments in the workday.

Field tip: if an app gives you a code answer without the article citation, do not trust it. Every answer needs a specific NEC reference you can verify, whether that is 210.8(A)(6) for kitchen countertops or 314.16(B) for box fill calculations.

What this means for you

If you are a working electrician deciding where to put your time and money, the answer is not either or. Spend the money on Mike Holt material for the sections of the code you work in most. Keep an accurate code reference app on your phone for the 30 times a day you need a quick citation. Verify both against the actual NEC when the stakes are high.

Ask BONBON passed the accuracy test against Mike Holt at 95 percent on quick lookup questions. That is good enough for field use, not good enough to replace a real code book on a complex install. Know the difference and you will not get burned.

The next review in this series covers how the app handles the 2023 code cycle changes that most electricians are still catching up on. If you hit a code question today that an app got wrong, send it over. Real field questions make every review sharper.