First of all I want to say thanks for everyones input. What I am doing is refeeding a 475' piece of 3000amp busduct. The Ideal way would be to extend the duct, however it was installed in 1951 and I have not been able to find matching duct.
I wouldn't really call this a high rise. It's 5 stories, 1.5 million square feet. Complete rehab. All switch gear and bus duct is original. We have redone the risers and panels on parts of 3 floors. The building had it's own generators when built. We removed those and tied it into POCO's grid last year. If anyone knows where to get about 100 feet of 50 year old Westinghouse 3000amp bus duct, then I won't need that pull box.
