rack power question

You're quite welcome.

There is a whole 'nother side to this, too, especially for those who run DC
power. The ampacity of conductors is quite a bit higher for DC; I have a
copy of the best book on that subject, written by a telco engineer. Let's
see:

"DC Power System Design for Telecommunications" by Whitham D. Reeve, Wiley is
the publisher.

This is an expensive book; about $100 from Wiley; low price on Amazon right
now is $75.75. This one goes over EVERYTHING when it comes to DC power
distribution design and implementation. It was worth the price I paid,
that's for sure.

We have two 200A Lorains here, with A battery being 450Ah of C&D flooded
cells, and B battery being a bank of 4 135Ah 12V sealed AGM batteries. Our
core switches and all but one of our core routers have DC power supplies.

Incidentally, all of this is fresh to me primarily because I'm in the process
of building a new datacenter and moving our existing equipment into it,
primarily for RFI mitigation reasons.