The National Electrical Code Is a Minimum Safety Standard
The blank in that exam sentence is safety. The National Electrical Code is a minimum safety standard, and Section 90.1 says so in three short paragraphs that are worth reading once a year even if you have been in the trade for twenty.
What 90.1 actually says
Section 90.1(A) gives the purpose: the practical safeguarding of persons and property from hazards arising from the use of electricity. That is the whole mission statement. Not efficiency, not convenience, not longevity. Safety.
Section 90.1(B) sets the boundary: the Code contains provisions considered necessary for safety, and compliance with it and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use. That last clause is the one to quote when a customer asks why a Code minimum panel is a bad idea for a house that will get an EV charger and a heat pump in five years. The Code says outright that meeting it does not mean the installation is adequate for the future.
Section 90.1(C) is blunt about the audience: the Code is not intended as a design specification or an instruction manual for untrained persons. It tells you the floor, not how to build. Load calculations, coordination studies, and equipment selection still belong to a qualified designer.
Why the minimum framing matters on a job
Everything in the Code is a floor you may exceed, never a ceiling you must hit exactly. You may install 12 AWG on a 15 amp circuit. You may run a 200 amp service to a house that calculates at 125 amps. You may put in more receptacles than 210.52 requires. None of that is a violation, because exceeding a minimum is always permitted unless a section specifically sets a maximum.
The reverse is where people get in trouble. A drawing that specifies 4/0 copper does not authorize you to drop to 3/0 because the Code allows it. Section 90.4 places enforcement with the authority having jurisdiction, and the AHJ enforces the approved plans as well as the Code. An engineer who specified above Code did so for a reason, whether that is voltage drop, future load, or a client standard, and changing it is a design decision that is not yours to make on your own.
Section 90.2 defines the scope, covering installations of electrical conductors, equipment, and raceways for public and private premises, and 90.2(D) lists what the Code does not cover, including utility owned installations, ships, railway rolling stock, aircraft, and automotive vehicles. Section 90.3 explains the arrangement: Chapters 1 through 4 apply generally, Chapters 5, 6, and 7 supplement or modify them for special occupancies, equipment, and conditions, and Chapter 8 for communications systems is not subject to Chapters 1 through 7 unless specifically referenced. Chapter 9 is tables, and the informative annexes are not enforceable.
That last point about Chapter 8 catches people constantly. It is why a rule in Article 300 does not automatically apply to a data cable, and why Article 800 has to restate access and support requirements in its own language rather than pointing back to Chapter 3.