Shelly Housing (Gen1 1/1PM)

Disclaimer: Be aware that in many jurisdictions, mains voltage installations must only be executed by qualified or even only certified individuals! This model description as well as the attached pictures are only for demonstration purposes.  For installation instruction and wiring diagrams, consult Shelly's official documentation

Note: In some plug designs (such as the German Schuko plugs), there is no polarization or keying mechanism to ensure the fixed orientation of the live (phase) and neutral conductors. As a result, it cannot be guaranteed whether the Shelly switches the live or the neutral line. This may lead to situations where a connected device appears "off" while still being electrically live.

Note: Pull-test every connection.

Some of my printers are placed inside cabinets, using Prusa Connect I can start print jobs remotely but I don't want to have them online all the time. I had a few spare first generation Shelly 1 WiFi relays laying around, so I did a quick adaption of my Shelly PM Mini Housing.

Additionally Required Hardware

¹ Alternatively, insulated butt connectors can be used.

² I strongly suggest implementing some sort of strain relief. Use either zip ties or the provided strain relief ring. The latter can be fixed to the cable using super glue. You may have to scale the ring mesh according to the cable you're using. The provided file is supposed to go on a 7mm outer diameter cable.

Features

Find a list of all the sophisticated design features of this model in the referenced original upload.

Print Instructions

The compliant mechanism on the base will work best printed in PETG, but ABS or ASA will be fine as well. I advise against using PLA due to the potential heat generated by the Shelly. PLA may soften, which is undesirable for a case containing mains voltage.

This model ist optimizes to be printed with a 0.4 mm nozzle. or the shell parts, you can use your default slicing profiles.
For the clamping bracket, I recommend using vase mode. Alternatively, if not using vase mode, place the seam in one of the bottom side corners to ensure a clean finish.

Assembly

Only attempt assembling this if you understand the risks involved with mains voltage!

For a detailed installation guide study Shelly's official documentation. My instructions here only cover the mechanical details. 

Preparation

Given the limited space within the housing, precise wire lengths are crucial for a successful assembly. To simplify the process, I’ve outlined the necessary wire lengths below. You will need the cables for both the input and output connections, as well as two additional pieces of brown wire to serve as the life wire.

For a secure connection, I recommend using ferrules on all wire ends. Note that the ferrules may need to be shortened slightly to fit properly into the terminals on the Shelly.

¹ Leave these long, so that in case of pulling on the cable, PE rips off last. 

Installation Order

Once your wires are prepared, follow this installation order:

1. Place the strain relief rings onto the cables.

2. Connect all the live and neutral lines as required. 

3. Dry fit everything and cut PE to length. Crimp on ferrules and connect using an inline WAGO connector or use an insulated crimp butt connector.

4. Flip the assembly upside down and place it in the top shell of the housing (the one without the locking feet). Make sure that the long neutral wire is between the PE connector and the Shelly. 

5. Position the strain relief rings and glue them in place.

Remarks

I don't provide a clamp version with a screw hole because I think it's a bad idea to drill holes close to power outlets.