Power supply cover with fused outlets

thingiverse

This is the 3rd version of a project that started about [4 years ago](https://www.thingiverse.com/thing:182462) and was followed by an [improved version](https://www.thingiverse.com/thing:235754) a few months later. I have used these power supply covers with all my 3D printers and Laser engravers in the past years and did not see any need for improvements ... until, one day, I created a short in one of the attached the power cables. As these cables were only used on a device using less than 2A, they were dimensioned accordingly - so the short did not burn the fuse of the powerful 30A PSU, but rather caused the relatively thin cable to start burning withing seconds... That's when I realized how dangerous a powerful PSU can be, if used without a fuse that is dimensioned according to the actual intended use. The built-in fuse or over-current protection which traps only when the maximum amperage of the power supply is exceeded will not prevent damage to attached circuits which only use a fraction of the maximum possible amperage. So this is why I went back to look at the design of my power supply cover again, this time with the aim of protecting each power outlet with its own fuse, whose value can then be chosen to fit the current used by the attached circuits. In this version of the project I added an automotive fuse holder for each of the 3 power outlets. These fuse holders use standard medium size blade fuses and can be ordered cheaply from eBay or AliExpress (I paid USD 1.06 per lot of 5). These fuse holders come also with a plastic cover, which we don't use here to save space. Instead of wiring the 12V output directly to the Molex or Tamiya sockets, the PSU 12V output now goes first through the fuse and only then into the socket. This allows us to protect each 12V output with a fuse that is specific to the intended use of the outlet. In my unit here, I have protected the three outlets with 15A, 10A and 5A fuses, respectively. Thus, the heatbed will be connected to the 15A outlet at the left and the extruder and motors to the 10A outlet in the middle. The 5A outlet at the right is a spare output that can be used to attach other gadgets. Another enhancement made in this version is to provide a choice of AC power switches. In addition to the small 10mm x 15mm rocker switch used in the previous version, the bigger 15mm x 21mm switch is now also supported. For all the rest, this version is identical to the [previous version](https://www.thingiverse.com/thing:235754), so please refer to there for further information on this project. In the files section, you will find the fully parameterized OpenScad source together with ready-to-print STL files for Molex 19-09-2029 and Tamiya connectors, in versions with and without fuse holder, and for 10x15mm and 15x21mm AC rocker switches. Note that for the Molex versions you also need to print the corresponding clips, and for Tamiya versions the corresponding frame object is needed. Note that I myself only use the Molex version of this project. While I also try to keep the Tamiya versions updated, I have not actually built them, so I cannot guarantee that they will work perfectly. _Update 2018-12-17: There is now a smaller, more compact version of the 12V/30A power supply on the market, so I have published today a [new version of this project](https://www.thingiverse.com/thing:3291998) adapted to new small form factor device._