Here I explain the function and the installation of the Power Shutdown Relay V1.2 from BigTreeTech at hand of an Ender 3 with BTT SKR min e3 V2.0 Mainboard.

I apologize for the flickering LED light.

3d-Files for the housing parts are available here: https://www.thingiverse.com/thing:492...

The printer enclosure's building instructions and 3d files are from Sen3D and can be found here (no affiliate link):
https://ultraenclosure.com/

00:00 Introduction
00:27 Connections on the mains power side
01:34 Connections on the low voltage side
03:59 Bits for the base functions
05:52 Bits for the reset switch (optional)
06:50 Bits for short circuit detection and power loss pin (optional)
07:52 Installation on the mains power side
12:22 Pinout on the low voltage side
14:55 Installation on the low power side
17:38 Firmware adjustments
20:30 G-code adaptation
21:10 Functional check