Based on your sketch, is the AHJ is requesting a 2-hour rating on the portion of the circuit that is 46kV? MI and Vitalink MC are being mentioned, but I believe those are low voltage conductors (<600V) which can't be used.
the 46000 switchgear does have overcurrent, I not sure of the size but its considerable
Where is this switchgear (Inside or outside the building)?
I should have said the only OCPD was at the main service entrance. The circuit is tapped on the load side of the 480v with no OCPD.
It is an old WWII building.
What voltage is the main service entrance? Is this 480V or 46kV? Is this a unit substation with MV switch, dry type transformer, and a low voltage section?
Can you provide a one-line showing the service point, 46kV switchgear, stepdown 480V transformer, etc. and what portion you are replacing with new?