Transformer - Installation

[EmmaBldg]

We have a project in an old factory building being renovated. We are installing a 150 kVA Transformer and the flooring is old hardwood tongue & groove boards with a brick wall. Do we need to provide a fire barrier under the transformer? Primary voltage 3-phase 208V, secondary 480V. I'm thinking we will have to pour a concrete pad? If so is 4" acceptable and how much bigger than transformer would it need to be? Any thoughts?

 

[tw1156]

450.21(B) exception no.2. We've used this before with the AHJ signing off on it. Max sure your transformer is compliant as well as the AHJ signing off on it before you go down that path though as I've encountered a few that have not approved of that exception.