apparently, the manufacturer has changed the power supply to different model
with different dimensions.
This is for old model, not newer ones.
Power Supply cover, Power Switch, Power cord socket
for Anet A8, Hesine, Senhai, M505, Omni etc priters.
utilize readily available switch/socket combination part,
this black switch was cheapest on ebay, but there are red and green switch versions too.
but you can modify the mesh to fit many other switches and sockets.
designed so that can be printed without any support, and should be able to install securely with just a single M3 bolt as shown.
Line goes to fuse then to switch then to the L terminal on Power Supply.
Neutral goes to N, Ground goes to Earth.