Many people approach the NEC as if it limits what they can do. That’s not at all the case. It’s a basic principle of the NEC that this is not the case.
If the NEC requires you to do X in application A, but not in application B, that doesn't mean you shouldn't consider doing it in application B. If doing it will make application B safer, then you probably should do it unless it’s not practical or the cost is prohibitive.
For example, you’re wiring a new break room at a factory. It has a sink, so you provide GFCI protection for the receptacles near the sink. You’re not required to provide GFCI protection for the convenience receptacles around the room, but should you? People will be handling liquids (including hot coffee, with inevitable spills), so it’s not a bad idea to just do that. Consider also the chili crock pot with the extension cord that someone is bound to walk on, too. For a small cost, you can avert a tragedy.
The NEC doesn’t stop you from making something safer. Its purpose is to provide the minimum requirements to protect people and property [90.1]. The Code Making Panel members can't think of every possible situation. It’s your job to assess the installation and go beyond bare Code compliance as the situation merits.
What's the intention of the requirement to do X in application A? Answer that question, and you may see other (non-required) applications (maybe even on the same job) where meeting that requirement will make the installation safer.
Taking the time to really understand the NEC enables you to connect these kinds of dots. You know there’s a requirement to do X, and even though it’s not specified by what you looked up for your application, you are aware of it.
The NEC isn't a design guide [90.1]. You are expected to use your own judgment in addition to following the NEC. And safety, though critical, isn’t the only issue.
Suppose you size your conductors to the minimum size determined by the requirements of Art. 310, but they are going to be in a run that’s long enough to cause a significant voltage drop. One of the nice things about conductors is they are relatively cheap. Whether you run three 12 AWG or three 10 AWG in that EMT, the material cost won’t vary much, and the labor cost won’t change at all. So why not just upsize the conductor and eliminate the life-long energy loss (and other problems) with that circuit?
The NEC doesn’t require you to accommodate voltage drop, but good engineering principles dictate that you do.
So we’ve addressed safety and efficiency issues not mandated by the NEC. What other types of issues might the NEC not mandate? Maintainability is one.
Much of the downtime that factories endure stems from “cost savings” during specification and installation of the equipment. A big area for downtime waste is the maximization of revenue per square foot calculation that assumes the equipment always runs and never needs people to work on it to keep it running. Go beyond the NEC to think this out so that revenue actually is maximized. For example, is there enough room for a maintenance cart and the two electricians needed to fix this thingamabob when it eventually fails, as you know it will?
Then we have the typical electrical panel. Why does it not have convenience receptacles (for test equipment) and lighting, all provided from a breaker that is not in that panel? To do many kinds of work in that panel, you open all of its breakers and then open its main.
What if that panel powers everything in the area, including the lights? Now you’re in darkness and have no power for the test equipment needed for this work. So you run extension cords from halfway across the plant. Same costly drill, every time someone needs to do much work in that panel. If only someone had considered maintainability rather than, “It passes Code, so my job is done.”
The NEC doesn’t mandate infrared windows for industrial switchgear. Given the safety advantages, maybe someday it will. Given the cost advantages, astute CFOs already should mandate them in their facilities already.
Convenience is another issue. Walk through almost any home, and you notice the receptacles are installed per the “What can I get by with to pass inspection” mentality rather than considering a good design for the convenience of the occupants. That’s why people buy all those multi-outlet expanders and run extension cords all over the place. Don’t you sleep better at night knowing there’s a bunch of extension cords on your combustible carpet? Sure you do.
You need to think beyond the NEC by asking basic questions. What kind of equipment is any room likely to have, where might it go, and where should you place receptacles?
Why does a typical bedroom have 12 feet between receptacles? And only one wall has more than one receptacle? Gee, it’s got two receptacles. What a treat.
The answer is that the builder didn’t care that the intended headboard wall would need a place for the occupants to plug in an alarm clock radio, two smart phone stands, two electric blanket controls, and two nightstand table lamps. How do you plug those into only two receptacles? And many people have even more items along that wall.
The living room is another receptacle desert with cords often run under the carpet. Keep in mind that these aren’t the portable cords you enjoy at work. These are often drug store extension cords of dubious construction; why build in that hazard?
The way homes are miswired (to “save money”) is just an example of this kind of user-hostile design. It complies with the NEC minimums for the practical safeguarding of people and property, but it ignores the NEC’s 90.1 entirely.
Think of how this example relates to any commercial or industrial facility. How much money does the facility hemorrhage every day because of poor design? And what safety hazards lurk just because someone confused “not required by Code” with “not necessary for a good job?”
Yes, comply with the NEC. But don’t avoid complying with its intentions just because there’s not an explicit requirement (break room example) and don’t use NEC compliance as an excuse for providing a design that’s inconvenient, inefficient, or deficient in some other way you could have addressed.