Sonoff Basic - A Better Inline Case With Earth Connection

Ever wanted to put a Sonoff Basic smart switch inline with a trailing socket or extension? It's a reasonably 'want' but how do you do it when the devices aren't intended to be 'out in the open' and do not pass-through an earth connection?

Sonoff Basics are a really cheap way of adding 'smarts' to dumb devices (I used them LOTS). They work really well within things or hidden in a fixed position, away from inquisitive fingers. However, their (rather 'basic') enclosure only caters for the connected Live and Neutral wires. There is no space for strain relief on 3 core flex and no inbuilt way of passing an earth connection from the supply to switched side.

If you don't give a toss about electrical safety they can obviously be installed inline on a bit of flex but, I am not that person. I care about safety, not necessarily my own, but that of others!

I like to stick Sonoff Basics on flying extensions, floor lamps, table lamps etc. I needed to come up with a versatile method connecting the inline and in a safe manner.

The design I came up with encloses the entire Sonoff Basic and provides two layers of insulation. The Basic is mounted within the case using the screws supplied. There is strain relief in the form of cable tie 'tunnels'. For larger diameter cables, a single cable tie can be used. Thinner cables will need an additional cable tie around the cable. Most importantly (IMHO), there is space for a crimped earth connection to run underneath the Sonoff. The top and bottom of the case lightly snap together. This is good enough if the case will be inaccessible but there are also holes recessed for M3 cap head screws (minimum 15mm). I've also designed a couple of variations, a top with cable slot access for additional sensors and a base with external mounting holes for screwing to a surface (I use this in the loft, garage and shed).

This is a ground-up design created in Fusion 360. There are similar-looking designs available but, as is typical, tolerances are poor and there are very few with a 'nice' method of passing the earth connection.

3D print files for this design are available for a small charge on Cults3D.

This case design was used when creating the Sonoff Basic With Touch & Movement Sensors project.