No they don't. Server-grade redundant PSUs usually use a CRPS form factor, where individual PSU modules slot into a common multi-module PSU housing known as a P

No they don't. Server-grade redundant PSUs usually use a CRPS form factor, where individual PSU modules slot into a common multi-module PSU housing known as a PDB (power distribution board). Each module typically outputs only 12V and the PDB manages the down-conversion to 5V, 5VSB, and 3.3V. From there, there is only one set of power cables between the PDB and the system's components including the motherboard and any PCIe add-in cards. Additionally, there is a PMBus cable between the PDB and the motherboard so that the operating system and the motherboard's remote management interface (e.g. IPMI) can monitor the status of each individual module (AC power present, measured power input, measured power output, measured voltage input, measured frequency input, fan speeds, temperature, which module is currently powering the system, etc). PSUs can be removed from the PDB and replaced and reconnected to a source of power without having to shut down the machine or even remove the case lid. You don't even need to slide the machine out of the rack if you can get to the rear. Example: https://www.fspgb.co.uk/_files/ugd/ea9ce5_d90a79af31f84cd59d16e4673d9f72b1.pdf https://www.fspgb.co.uk/_files/ugd/ea9ce5_d90a79af31f84cd59d...