Breaking the tabs on the existing receptacle prevents one from having to use a jab saw or multitool to cut a hole in the gypsum wallboard or plaster and install

Breaking the tabs on the existing receptacle prevents one from having to use a jab saw or multitool to cut a hole in the gypsum wallboard or plaster and install a cut-in/old work box to add a 2’d duplex receptacle: https://www.homedepot.com/c/ah/how-to-install-remodeling-boxes/9ba683603be9fa5395fab909f01e786#:~:text=To%20prepare%20the%20surface%2C%20use,inside%20for%20a%20test%20fit. https://www.homedepot.com/c/ah/how-to-install-remodeling-box... Any 15A or 20A duplex receptacle can have the tabs broken to get two separate 15A or 20A simplex receptacles, you don’t need a 5-20R for that, a 3-wire 5-15R works just fine. Someone upthread mentioned 1.2kW load which a 15A receptacle handles just fine: .8*120*15=1,440W continuous. Bumping that up to 20A only gets you an additional 480W of continuous load: .8*120*20=1,920W. A continuous load is one that runs for 2 hours or longer, the overcurrent protection and wire must be upsized by 1.25x (or derated to 80%) Most receptacles in homes are wired with 14/2 romex which is only good to 15A (in homes, which use the 60C ampacity column) which is why I suggested pulling another run of 14/2G romex and breaking the tabs. Pulling 14/2 romex to an existing receptacle usually isn’t that hard if you have a fish tape. AFAIK computer PSUs can’t easily use 240V power without a PDU in the middle, but I’m likely wrong on that, especially for server PSUs.