Every company needs to save money. So when you're doing an electrical installation, just how close to NEC compliance do you really need to be?

The NEC answers this question in 90.1, making four important points:

  1. It's about safety.
  2. It's not necessarily going to provide you with a money-saving, efficiently operating design. For that, you may need to exceed Code requirements.
  3. It's not a design manual or tutorial.
  4. It's about safety.
The first and fourth points aren't explicitly redundant in the NEC, but the underlying message is. You follow NEC requirements to get a safe installation. You may need to exceed those requirements to satisfy engineering considerations.

Completing an installation that "almost" meets Code to "save money" not only produces an unsafe installation, but it probably costs more than it saves. For example, you could cheat on the Art. 310 ampacity tables, using the next size down option to "save money," but the resulting insufficient ampacity may cause loss of operations followed by expensive repair. On the other hand, exceeding the requirement by using the next size up reduces electrical consumption enough to pay for the added conductor costs fairly soon.