At a physics-research site, I had the privilege of escorting a couple of real-decent PEs for the initial data acquisition for a couple-of-mile 8-MVA distribution tie line with switchgear mods. NFPA 70 was early in the standards boilerplate for the work, and were virtually universal for dealings involving electrical systems at the operation.
Their contract as-found and as-built drawings listed switchgear dimensions to ⅛-inch. They took a lot more interest and dedication to the job than most in-house engineering folks. [Our detailed specs for a very complete, years-evolved tried-and-true 13.8kV metering and relaying section showed up verbatim on another site of ‘theirs’ about a year later…]
Competent PEs make the NEC and updates their routine business. A 230kV utility-owned switchyard still has numerous aspects where the NEC is perfectly applicable—with nothing else nearly as appropriate. Ratings of miles of bundled DC- and AC-circuit SIS-wire ampacity calculations and overcurrent protection is one area. Why reinvent the wheel? It is one very useful and widely referenced ANSI standard.
