Any UPS with a rating of 1500 VA or below can be plugged into a standard household receptacle/socket.
UPS models with ratings higher than 1500 VA use input plugs that can’t be plugged directly into a standard receptacle. Many higher rated UPS (above 1500 VA) may also be hardwired directly into the electrical distribution panel at the installation location by a licensed electrician.
Many UPS models offer a fixed set of input and output receptacles. Other UPS models can be configured with a custom set of input and output connections.
For reference we’ve included the following chart to help you visually confirm input and output plug/receptacle options:
* 5-15P can plug into 5-20R
R = Receptacle, P = Plug, L = Locking
For the number before the hyphen:
5 = 125V, two-pole, three-wire (grounded)
6 = 250V, two-pole, three-wire (grounded)
14 = 125/250V, three-pole, four-wire (grounded)
The number after the hyphen indicates the amperage. For example, the L5-30R is a 30A receptacle.