There are electric ovens and kilns that operate for different purposes, at different temperatures.
(note: apparently going with single-phase 240 volts is a good idea [2] [3])
The popular Evenheat LB18 maxes out at 2200°F / 1200°C.
Depending on what the kiln will be used for, it may need to reach 2270°F / 1250°C for mid-range clays, or up to 2460°F / 1350°C for high-fire porcelain.
TODO: temps for forge-welding