Correct it is a (was) 480/277v 4wire system.
Like stated by moderator from my notes, this is a split panel. Top half was for HVAC and bottom half for general loads.
This is a prime example why main lug panels, using six disconnect rule, for service equipment should be outlawed.
This had to have been going on for some time. 8am secretary reported to fire alarm co., that the alarm was going off, and if they could come reset it. Alarm co. shows up, (what do you think 1/2hr?) Opens electrical room door, see's the panel glowing and calls fire dept.
Fire dept shows up and wont do anything because there is no main disconnect. Leaves the scene and never returns or follows up. I show up 50minutes after initial call from secretary.
POCO still not on scene. Panel completly cooked by this point obviously.
POCO shows up, opens padmount xfmr (13.2kv-480/277) and opens primary switch.
A and C phase primary fuses blown. What if fuses didnt blow??
Dust on the insulators for sure. This panel is 30years old, and many times this panel cover has been left off. Very dusty and dirty room too.
