Part of my series of enclosures designed for Shelly smart devices and Wago 221 connectors.

• Shelly box for T&E 3x slots and wago 221 connectors 

• Shelly box for inline flex wire and Wago 221 connectors

• Shelly box for 2x flex wires and wago 221 connectors

• Shelly box for 3x flex wires and wago 221 connectors

• Shelly quad box for 2x devices/5x relays/5x flex wires and wago 221 connectors (this one)

Enclosure for 2x Shelly 2PM dual relays, 5x flex wires and wago 221 connectors

This box was designed for wiring 4 appliances with wago 221 connectors and two Shelly 2PM smart relays.

Electrical safety

• Mains electricity carries danger of death. Please don't attempt to use one of these with real circuits unless you are competent and aware of health and safety procedures.

• Use PETG or other fire resistant materials other than PLA.

Purpose and features

The enclosure is designed to connect 5 flex wires to 2 shelly 2pm devices using wago 221 connectors. I needed this to switch 4 appliances with 2 shelly 2pm devices.

Shelly device support: Shelly 2PM

Wiring support: The enclosure was developed with 3 conductors 1.5mm2 section flex cable in mind (e.g. 3183Y), therefore thinner wires will leave a gap on the entry holes and thicker wires may (will) not fit. NOTE: it would not be difficult to file the holes to fit larger wires, but please bear in mind that Shelly devices are not rated for very high loads, so if your application requires >1.5mm2 section wire then your main problem is not the wire entry hole.

Wire strain relief: Each flex wire entry port has slots for fitting a cable tie as strain relief for the wires.

Attachment holes: The box has counter-sunk holes to attach it to a surface.

Cooling slots: There are cooling slots all around and above/below the shelly devices.

Lid fitting: The lid attaches to the box using 4x M3 screws (5-10mm max) which thread into M3 heat inserts to be installed on the box.

Printing notes

• The lid requires supports on the bolt hole counter-bores, otherwise it will not print cleanly (in my case it didn't)

Version control

Version 2.3 - 20/11/2025

• Adjusted location and size of venting holes.

Version 2.2 - 12/12/2024

• Adjusted internal spacing for wire routing, specifically 8mm extra between each 5 port wago (+16mm side to side) which also increased the space between the shelly devices, 10mm extra between the 5 port wago and the 3 port wago (+10mm length)

• Wire entry hole spacing adjusted

• Height extended by 1mm

Version 2.1 - 11/03/2024

• Updated (reduced) cable tie shelf width, validated lid locator and wago pad locations

• M3 heat thread inserts instead of square nut slots or holes for tapping

• Attachment bolt holes on the inside of the box rather than outside brackets

• Cable tie pads inside the box as opposed to accessible from the outside (enables refitting ties without dismounting the box)

• Shelly slot adjusted for compatibility with multiple models