Thanks for the response George. The breakers we are going to propose Will be reconditioned ITE breakers.(The gear is ITE Gould) One thing I didn't mention is both added breakers are required to have kirk key interlocks with the main. This is one of the reasons for using breakers as opposed to fused switches. The other reason is the physical size of the 800A switch. The largest existing bucket is 400A. The fact that we are proposing to install breakers by the same manufacturer as the gear should maintain any listing issues and if we have to get a third party certification, that is not a problem either. I think after I get the available AIC from the utility I will propose this to the engineer of recored and see how it goes.
BTW-There is not a huge motor contribution to fault current here. There will be some but the building is mostly office and wearhouse space.
