For my version of the ubiquitous power supply cover design, I wanted a combination of the functionality of papinist's cover with LCD power meter with the IMHO better looks of this solution by TNS. To be honest, I'm not entirely content with the resulting look, but it does its job.
My A8 is from December 2017 and has a S-240-12 power supply. See papinist's design for the shopping list and wiring instructions.
Attention: Use at your own risk! You are dealing with dangerous amounts of current! Use proper insulation with all contacts and be careful when inserting the power plug. I intentionally strengthened the right hand part, but if you press too hard, it may break anyway, depending on the quality of your print.
All my Anet A8 designs:
40% to make it resistant against push-in forces from plug
I printed this with the front face down in PLA. Upright as provided should work as well, and will make it more sturdy against pushing forces when inserting your plug.