If you have large UPS that weighs over 250lbs that I’m installing in a Server Rack, we provide a Rackmount Shelf that can support it. A large heavy UPS can easily be installed in a Server Rack using a Heavy Duty Fixed Shelf. This Rackmount Shelf can easily support up to 500lbs and will install into any Server Rack. The RackSolutions Part Number 1USHL-116.