Yes, but you mentioned industrial facilites which the NEC does cover. So not sure if this is a POCO generating plant or maybe its at an industrial facility.
State jurisdictions get messy. You can’t just read the scope of NEC and NESC because they do not have a correlating committee. IEEE and NFPA rivalry. OSHA has made it clear as far as generators and equipment in generating plants. It has nothing to do with SIC Code. If the generator is intended as emergency backup it follows 1910.300-399. That’s NEC. If ir is a cogen or anything else similar intended for continuous power generation it falls under 1910.269. But within those facilities equipment that is purely utilization such as plant lighting and receptacles falls under 1910.300-399. Pure generation, transmission, and distribution equipment falls under 1910.269. Mixed use such as a distribution panel that powers say a generator PLC and lighting follows BOTH sets of rules. The grey area is in what OSHA means by power distribution. Using a very strict interpretation an MCC for instance is probably purely utilization equipment. But do we draw the line at service entrance or do we include feeders, switchgear, switchboards, and maybe even panelboards as distribution subject to 269 rules? So far osha has avoided defining this. It matters because .269 only allows qualified workers but equipment only needs to meet standards such as ANSI. 1910.300-399 equipment must be third party NRTL tested.
I once worked at a facility with a port, air strip, mine, railroad, cogen, fed from Duke transmission lines with miles of its own lines, and semi-permanent construction contractors on site. The reality is very few rules are different from one jurisdiction to another. For instance mine rules require physical removal of wiring that is not in service. Anyone that has ever worked in an old industrial plant can appreciate this rule. Another difference is 1910.300-399 requires LOTO where possible while it is just a good idea under .269 and not required for construction at all (read 1926 both sentences on electrical before arguing otherwise).
NFPA 101 life safety code, NFPA 10 alarm code, and the hospital code require generators and the level of criticality. NFPA 110 standby power systems and NEC get into implementation. Very few emergency power systems are actually legally required but there are a ton of others out there and it should be obvious many are a good idea even if not required.
