110.2 - APPROVAL (Or: "No, Your Buddy's Homemade Panel Ain't Code")
The Straight Talk
Alright, listen up. Section 110.2 is short, sweet, and absolutely critical. It says that every single piece of electrical gear and every conductor you install has to be approved. Period. End of story.
Now, before you roll your eyes and think "Yeah, yeah, I know," let me tell you what this really means: You can't just slap in any old crap because it was on sale at Sketchy Steve's Electrical Surplus or because your brother-in-law made it in his garage. The AHJ (that's the inspector, for you first-years) needs to say "yes" to it, and they're gonna base that decision on whether it's listed, labeled, or otherwise meets their approval.
This section is basically the NEC's bouncer at the door saying, "You're not getting in without ID."
Think of it this way: If the gear doesn't have the blessing of a recognized testing lab (UL, ETL, CSA, etc.) or the specific approval of your local inspector for that special snowflake situation, it doesn't belong in your installation. Your opinion doesn't count. My opinion doesn't count. Only the AHJ's opinion counts.
The Informational Notes (The Fine Print That'll Save Your Bacon)
The Code gives us two informational notes here, which is code-speak for "Hey dummy, read these other sections too":
Info Note #1 points you to Section 90.7 and 110.3. Translation: "Go read about how equipment gets examined for safety and what 'listing' actually means." These sections are your backup singers—they harmonize with 110.2 to give you the full picture.
Info Note #2 sends you to Article 100 for definitions. This is important because "approved," "identified," "labeled," and "listed" are NOT interchangeable terms, even though we use them that way at the supply house lunch counter. Each has a specific meaning, and inspectors love to nail people who don't know the difference.
Key Takeaways (The Stuff You Better Remember)
🔧 Every conductor and piece of equipment must be approved - no exceptions, no excuses, no "but it works fine"
🔧 "Approved" means acceptable to the Authority Having Jurisdiction (AHJ) - that's your local inspector, and they have the final word
🔧 Listing by a recognized testing lab is your best friend - UL, ETL, CSA, and others do the heavy lifting so the inspector doesn't have to
🔧 No homemade gear - unless you can get your AHJ to specifically approve it (good luck with that)
🔧 The definitions matter - "Approved," "Listed," "Labeled," and "Identified" are not the same thing (see Article 100)
🔧 This applies to EVERYTHING - from a $50,000 switchgear lineup to a $2 wire connector
Real-World Scenarios (Where This Comes Back to Bite You)
Scenario #1: "The Supply House Special"
You're doing a resi service upgrade, and you find a screaming deal on panels at a supply house going out of business. You load up the truck with ten panels at 60% off. Life is good!
Fast forward to inspection day. The inspector takes one look and says, "Where's the UL listing?" You look closer—there's a sticker, but it's from "Bob's Testing Laboratory and Bait Shop." The inspector red-tags your job.
The lesson: If you've never heard of the testing lab, neither has the inspector. Stick with recognized names. That "deal" just cost you a panel replacement and a return trip. False economy, my friend.
Scenario #2: "The Modified Disconnect"
You're on a commercial job, and the engineers spec'd a fused disconnect in a location where it won't fit. Your foreman, being "creative," decides to have the shop guy cut it apart and reweld it smaller.
Congratulations! You just voided the listing, and that modified equipment is no longer approved. The inspector will make you rip it out even though it's "technically" safe. The listing covers the equipment as manufactured, not after your shop guy gets creative with a plasma cutter.
The lesson: Once you modify listed equipment, it's no longer listed. Field modifications = inspector headaches = your problem.
Scenario #3: "But Amazon Had 5 Stars!"
A homeowner doing their own work (God help them) orders a "200 Amp Main Panel" from overseas on Amazon. It's got great reviews! Five stars! "Works great," says Jeff from Wisconsin!
They call you to connect it because they're afraid of the meter base. You show up and there's not a UL mark anywhere—just some CE marking and Chinese characters.
The lesson: You politely explain that you can't touch it, and they need to order an actual listed panel. E-commerce is great, but electrical equipment approval isn't a democracy. Jeff from Wisconsin's five-star review doesn't trump the NEC.
Scenario #4: "The Legacy Gear Shuffle"
You're doing a tenant improvement in an old building. You want to reuse some existing breakers and equipment that's already installed to save the customer money. It's old Square D—good stuff, works fine, no damage.
Here's the thing: Just because it WAS approved when it was installed doesn't mean you can use it for NEW work without verifying it still meets current standards and that the AHJ is cool with it. Most inspectors will accept listed equipment that's in good shape, but some applications or jurisdictions might have specific requirements about age or obsolete equipment.
The lesson: Have the conversation with your inspector BEFORE you commit to reusing old gear. Usually it's fine, but sometimes it's not, and you don't want to find out the hard way.
What to Study (For Your Exam and Your Career)
When you're studying 110.2 for any electrical exam (apprentice, journeyman, or master), focus on these money points:
📚 Know that "approved" = acceptable to the AHJ - this is the #1 test question from this section
📚 Understand that listed equipment is generally approved - but listing alone doesn't automatically equal approval in weird situations
📚 Memorize where Article 100 is - because half the test questions will require you to look up definitions, and you need to get there FAST
📚 Know the difference between:
- Approved - Acceptable to the AHJ
- Listed - Equipment tested by a qualified lab and published in a list
- Labeled - Equipment with a label from the testing org
- Identified - Marked for a specific purpose or use
📚 Remember that 110.2 works with 110.3 - they're like Batman and Robin. 110.2 says it must be approved; 110.3 tells you how to install it correctly
📚 This is an "entire installation" rule - It doesn't just apply to panels and disconnects; it applies to wire nuts, receptacles, wire, everything
The Bottom Line
Section 110.2 is the NEC's way of saying "Don't be a cowboy." Use proper equipment from recognized manufacturers with proper listings. Your creativity is appreciated in other areas—like how you route conduit or how many sticks of EMT you can carry at once—but NOT in deciding what equipment is safe.
When in doubt, look for the UL or ETL sticker. When you can't find it, call the inspector BEFORE you install it. Nobody ever got red-tagged for asking first.
And remember: The inspector isn't trying to ruin your day (usually). They're trying to make sure nobody dies from your work. That's a pretty reasonable goal.
Now get back to work, and keep it listed, people! 🔌⚡
Stay safe out there, and remember: If it doesn't have a listing mark, it doesn't belong in your truck.