Let's face it... POCO's play fast and loose with the rules. We have to follow code, but the POCO's do anything they want.
Perfect recent in the case of the "utility in question" example: POCO comes out to reset a CB on a pole XFMR that keeps tripping. The XFMR feeds two commercial buildings. Solution? Simply replace the 150KVA with a 225KVA! Of course, none of the feeders are upsized, so what happens? A nice manhole explosion and the building loses power.
The reason the CB kept tripping was the insulation rotted away in the manhole, resulting in an intermittent fault. But the 500 MCM cable (parallel feed) was no longer a match for that 225 KVA XFMR, so when the fault occurred, instead of trip they got boom.
Residential is even worse. 60-100A service upgrades to 200A are almost always done without upgrading feeders. You feel kind of stupid connecting a big fat 3/0 to a puny #2, but that's what done.
Heck in my house, I got a 2/0 copper feeder coming into a J-box, which feeds 2 of my neighbors via #4 or #2 (I forget which now, it's sealed) aluminum, which in turn feeds their neighbors with #4 or #2 as well. I'd hate to be the ones on the end of the line. So here I got a 3/0 copper connected to a #4 or #2 aluminum from the POCO and all is good in their book.
Now I realize that services often do not reach their maximum potential load, but the POCO should size their equipment to deal with such load. Anything less is what leads to the problems we're been seeing. A good place to start would be to force the POCO to follow the NEC just like the rest of us have to.
Joe
