Darn this is hard to convey.
One of the NEC’s major goals is to prevent fires. This is why the NEC is actually chapter 70 in a larger NFPA manual. Here it is. The NEC doesn’t apply to utility cables, they don’t run inside this house, so no house fire. They have their own industry specific codes. OK?
Ok, lets say this isn’t enough. For a service to be upgraded the new cables, have to be snipped. Thus requiring the utility to be called. At this point they ask questions, allow work to be done (issue a job #), etc. They got the information. Temp splice are put in by the home electrician, and then the utility comes out and puts in perm splices. They are made aware, and even have a line person check out the cables. Since it’s their equipment, they have a vested interest in keeping it safe. <information per our local utlity>
P.S. Sorry, typing out this seemed challenging; so I didn’t flame, just wrote out what’s what. Maybe a online teacher like Paul can better explain why.