Article 90.2: Where the Hell Does the NEC Actually Apply? (And Where It Doesn't Give a Damn)

The Straight Talk

Alright, listen up. Article 90.2 is basically the NEC telling you, "Here's where I'm the boss, and here's where you can't blame me if something goes sideways." Think of it like jurisdiction—cop A has their beat, cop B has theirs, and sometimes nobody's got jurisdiction (looking at you, cruise ships).

What's Covered (Where You Better Know Your Code):

The NEC covers damn near everything electrical you'll touch in your career on land-based installations:

• Houses, commercial buildings, mobile homes, RVs, and even floating buildings (if it floats but stays put, you're in NEC territory)
• Yards, parking lots, carnival setups, and industrial substations
• Anything that connects to the power supply
• Utility buildings like offices and warehouses (but NOT the actual generating plants or substations—they play by different rules)
• Shore power at marinas (boat owners shocking themselves is apparently our problem now)
• EV charging and bidirectional power flow (yeah, your truck can now power your house during an outage—welcome to the future, sparky)

What's NOT Covered (Where the NEC Throws Up Its Hands):

Here's where the Code says "not my circus, not my monkeys":

1. Boats, ships, planes, and trains (actual moving vehicles)—They've got their own codes because salt water, aviation fuel, and 200 mph winds create special kinds of hell the NEC doesn't want to deal with. Exception: floating buildings and the shore side of marina power ARE covered.

2. Mines—Underground mining has its own federal regulations (MSHA) because when things go wrong a mile underground, it's a whole different ballgame.

3. Railway power systems—The electricity that runs the trains themselves, not the stations or maintenance buildings.

4. Utility-controlled communication equipment—That Verizon box on the pole? Not your problem. Their engineers, their liability.

5. Utility-owned generation, transmission, and distribution—This is the big one. Power company stuff on their property or easements is theirs to wire. You know that transformer on the pole or pad? That's where your jurisdiction ends and theirs begins. Service point matters, people!

The "Why Does This Code Even Exist?" Speech:

The NEC exists for ONE reason: keeping people alive and buildings un-burned. That's it. It's not here to make your installation Instagram-worthy, it's not a design guide, and it sure as hell isn't "Electrical Work for Dummies."

Think of the Code as the minimum requirement to not kill somebody. It doesn't care if your installation is:

• Efficient
• Convenient
• Pretty
• Adequate for future expansion
• Gonna make the customer happy when they want to add 47 more circuits next year

The Code says: "Don't overload it, don't let it shock anyone, don't let it burn down, and you're good." Everything else is on you and your design skills.

KEY TAKEAWAYS (The Stuff You Better Remember)

✓ THE NEC COVERS:

• All building installations (commercial, residential, industrial)
• Mobile homes and RVs
• Floating buildings (docks, floating homes)
• Yards, parking lots, carnivals
• Shore power at marinas
• EV bidirectional power systems
• Utility-owned buildings (not substations/plants)

✓ THE NEC DOES NOT COVER:

• Ships, boats, planes, trains (moving vehicles)
• Underground mines
• Railway electrical systems (the train power itself)
• Utility-owned communication equipment
• Utility generation, transmission, and distribution on utility property/easements
• Service drops/laterals on utility side of service point

✓ THE PURPOSE:

• Practical safeguarding of people and property
• NOT a design manual
• NOT an instruction guide for homeowners with YouTube PhD's

✓ CODE COMPLIANCE MEANS:

• Safe (won't kill anyone)
• Does NOT automatically mean adequate, efficient, or future-proof
• Minimum standard, not best practice

✓ SERVICE POINT MATTERS:

• Utility side = utility rules
• Customer side = NEC rules
• Know where that line is drawn!

REAL-WORLD JOBSITE SCENARIOS (Why This Actually Matters)

Scenario 1: "But the Boat Owner Said..."

You get a call to wire a 50-foot yacht docked at a marina. The owner wants you to install a new panel and run circuits throughout the vessel.

The Problem: The boat itself isn't covered by NEC—it falls under Coast Guard/ABYC standards. BUT—the shore power connection, the dock receptacle, the GFCI protection, and the leakage current monitoring? That's ALL NEC territory.

The Lesson: You can wire the dock and shore power equipment, but tell Captain Moneybags he needs a marine electrician certified in ABYC standards for the work on the actual boat. Don't be the guy who gets sued when his electrical work sinks a $2 million yacht.

Scenario 2: "The Utility Says It's Your Problem"

You're at a commercial job. There's a problem with power quality—flickering lights, voltage sags. You trace it back to the transformer on the utility pole. You call the utility, they say, "It's on your side of the meter, your problem."

The Problem: You need to understand the service point (usually the meter, but not always). Utility owns from the source to the service point. You own from the service point into the building.

The Lesson: Check Article 100 definitions for "Service Point" and 230.70 for service disconnect location. If the problem is truly on their side, escalate with the right vocabulary. If it's on your side, you're pulling wire, buddy. This scope question determines who's paying for what.

Scenario 3: "The Mine Wants an Electrician"

A mining company calls you to do electrical work at their site. Sounds like good money, right?

The Problem: If it's underground mining work or the mobile mining equipment itself, the NEC doesn't apply—MSHA (Mine Safety and Health Administration) regulations do. You could be Code-perfect and still be violating federal mining law.

The Lesson: Surface buildings at mines (offices, shops)? That's NEC work. Underground or on the equipment? That requires MSHA training and compliance. Know which world you're in before you quote the job.

Scenario 4: "The Carnival's in Town"

You get hired to wire up temporary power for a traveling carnival—rides, game booths, food trucks, the works.

The Problem: Some guys think temporary carnival wiring is the Wild West. WRONG. Article 90.2 specifically includes carnivals. That means temporary wiring methods (Article 590), GFCI protection, proper disconnects, the whole nine yards.

The Lesson: Just because it's only there for two weeks doesn't mean you can hack it together with zip cord and duct tape. Carnivals are covered, and when rides full of kids are involved, you better believe the inspector's going to be crawling all over your work. Plus, see Article 525 specifically for carnivals, circuses, and fairs.

Scenario 5: "But Code Doesn't Require That!"

Customer wants to add a bunch of circuits for future expansion. Your quote includes a 200A panel. Customer balks: "Code only requires 100A for a house this size! You're ripping me off!"

The Problem: They're not totally wrong—Code minimum might be 100A. But Code is MINIMUM safety, not adequate for modern living or future needs.

The Lesson: Article 90.2(C) is your friend. Explain: "The Code keeps your house from burning down. It doesn't mean you won't be calling me back in three years when you want to add a hot tub, workshop, and EV charger. I can do bare minimum if you want, but here's what I recommend and why." Document their decision either way.

Scenario 6: "The Utility Won't Move Their Wire"

New commercial building. The utility's overhead lines run right where the owner wants the building. Owner tells you to just relocate them—you're the electrician, right?

The Problem: Those utility lines are under exclusive utility control per 90.2(A)(2)(5). You can't touch them. At all. Not even a little bit.

The Lesson: This isn't your scope of work. The owner needs to coordinate with the utility (which takes forever and costs a fortune). Your job is to point this out during pre-construction, not discover it when you show up with a crew. Check for utility conflicts early, document that it's outside NEC/your scope, and CYA with written communication.

WHAT TO STUDY (For Licensing Exams)

Examiners LOVE Article 90 because it tests whether you actually understand what the Code is (and isn't). Here's what shows up:

High-Probability Exam Topics:

1. Definition of scope - Know what's covered vs. not covered

   • Expect questions like: "Which of the following is NOT covered by the NEC?"
   • Answer will be: ships, aircraft, underground mines, or utility-owned transmission lines

2. Purpose of the Code - "Practical safeguarding" language

   • Expect: "The primary purpose of the NEC is _____"
   • Answer: practical safeguarding of persons and property (NOT design specification, NOT efficiency)

3. Code compliance vs. adequacy

   • Expect: "Compliance with NEC requirements results in an installation that is _____"
   • Answer: essentially free from hazard (NOT necessarily adequate, efficient, or convenient)

4. Utility exemptions - Service point concepts

   • Expect: "The NEC does not cover which of the following?"
   • Answer: Utility-owned service drops OR equipment on utility property/easements

5. Floating buildings vs. boats

   • Expect: "Shore power at a marina is covered by _____"
   • Answer: The NEC (the boat itself isn't, but shore connection is)

Study Strategy:

• Read 90.2 three times. I'm serious. It's only two pages and it frames everything else.
• Make flashcards: "Covered" on one side, list of covered items on the other. Same for "Not Covered"
• Memorize the purpose statement word-for-word: "practical safeguarding of persons and property"
• Understand the difference between "safe" and "adequate"—this concept appears in questions throughout the exam
• Know the utility exemptions cold—this determines responsibility and liability

Tricky Exam Questions They Love:

"An electrician is called to install wiring on a railway platform. Is this covered by the NEC?"

• Answer: YES—the platform/station building is covered. The train's electrical system is NOT.

"Does NEC compliance guarantee an adequate electrical system for future expansion?"

• Answer: NO—it guarantees safety, not adequacy or future capacity.

"Who has jurisdiction over the service lateral from the transformer to the meter?"

• Answer: Usually the utility (check local definitions of service point).

THE BOTTOM LINE

Article 90.2 is the bouncer at the club. It tells you who gets in (your jurisdiction) and who's on a different list (somebody else's problem). Know your scope, stay in your lane, and when something's outside NEC coverage, document it and point the customer to whoever DOES have jurisdiction.

And remember: The Code keeps people alive and buildings standing. It doesn't make installations pretty, future-proof, or customer-complaint-proof. That's where your skill, experience, and professional judgment come in.

The jobsite mantra: "I can do Code minimum, or I can do it right. One keeps you legal, the other keeps you from calling me back next year. Your choice."

Now get out there and wire something that won't kill anybody! 🔥⚡