If I use 392.80 to determine the ampacity of the conductors in a cable tray, how do I rate the ampacity if the conductors leave the tray in a raceway for approximately 6' and terminate at a switchboard? Do I need to follow 310.15 for raceway? Is there a maximum distance I can run them in...
Has anyone actually done the calculations in c57.116? I am confused because I thought they were solving for generator PU voltage based on the system voltage and generator max vars. However, the equation appears to be calculation the system voltage and mixing actual units with PU. Additionally...
Is there a reason why grounding transformer are wye-delta? If I had some auxiliary loads that I wanted to power from the secondary, could I make it wye (gnd) - wye (gnd)?
I have an existing 3MW generator running on a 12,470v wye system that is HRG. The 12,470 also feeds a 12,470 -2400 wye-delta transformer (ungrounded secondary). I want to add a 2400V generator to this bus, but also I was going to add a zig-zag grounding transformer to limit the over voltages...
I found an installation where a single phase 2400 L-N transformer was connected up using concentric neutral cable and the concentric portion connected to the neutral of the transformer. However, the cable was then spliced at a subsequent manhole to a single phase cable with a tape shield with...
I am curious why NEC article 240-101 which states the long time delay overcurrent protection on cables >600v can be set at 6x the ampacity is at odds with the ampacity tables. What is the thought process between the two.
