As a utility Meterman, I have voiced my opinion against feeding the fire pumps from the same transformer feeding the building. I have been told, that this is code compliant & per spec, but that does not make it right. (One customer told me he was only installing the fire pump for the insurance discount, because his building would never have a fire...)
I know if we respond to a building fire, the first thing we do is pull the cutouts to deenergize the building. This is required by the local Fire depts, to eliminate the risk of a Firefighter being electrocuted.
The best fire pump install is a free standing building fed from a different transformer, we have a few of these in our area. They are more expensive to install, but it is the best way to go.
