So after years of various different UK AC smart switches failing, overheating etc on me I decided to have a go at rolling my own one. It’s nowhere near as compact as the ones you can buy but it’s rated well over 13 amps (should be about 15amps and the relay i’m using is 30amps just to be sure 
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I’m currently waiting for a new case to print, wasn’t quite the right fit in this one and you’ll have to excuse the video quality too 
Screenshot of it hitting 12amps with the kettle
Were you just too close or exceeding the max current limit on the others? Its cool you made one but, hopefully you kmow what the problem was to begin with.
I haven’t been running too close to limits on my off-the-shelf ones to be honest, at most about 5 amps continuously running. Some units have lasted 1-2 years but the failure is always pretty worrying with fire hazards etc.
I’m happy with these units though and I know exactly what’s in them in terms of surge protection and overheating etc
I’ll upload another pic in the new case soon
Which units were failint? Before I left Facebook I was in the Shelly group and people were reporting relays that basically self-destructed. I definitely agree, the risk of fire is always there.
I’ve used lots and had failures all round pretty much although I haven’t used shelly - Meross, Sonoff and all sorts of different tasmota flashable units. Can’t think of more names off the top of my head. I’ve seen both relay and MCU issues and end up disconnecting the units without much more diagnosis if they’re hot to touch.
None of these brands advertise much in the way of lifespan/relay uses etc either which is disappointing…
I still have lots of off-the-shelf units in the house, but I’m now using my custom units for heavy duty loads. Case pics as promised (haven’t screwed the case together yet so excuse the ugly gap)
I hate to be negative about this, but what’s the flammability of that case material like? PVC junction and project boxes won’t support a flame, but I’m a lot less certain about 3D printable materials (i.e. I have all my mini-relay modules in electrical junction boxes for just this reason).
Completely agree, I wanted to get some metal cases made up but no idea where to start there to be honest…
It does have hard thermal cut-offs at 80C which is well below the burning temperature of PLA, at least.
Are those IEC 60320 C13 Connectors and C14 Inlets ? Pretty sure they are only rated at 10A in the UK ?
Indeed they are I’m not using the ones with IEC connectors for more than that other than the brief kettle test
Speaking of 10A ratings in the UK, you should check the cables/connectors on your kettle, you’ll be surprised
Kettles have a different connector, C15 and C16
I had a look around and there are companies selling 13A rated C13 power cords
Have a look at the AWG of the cable they use though, most are rated 10A or less but they get away with it because of the short duration of use.
I think as you said all C13/14 are only rated at 10A in the UK… the ones I’m using actually say 13A on RS, but on the plugs they clearly have two different ratings, 13A and 10A which I assume is for the UK.
I was looking around for better connector options for these that could actually be rated at 13A - ideally wanted to use a BS1363 socket for the load connector but C13/14 was the quickest option in the end since I’m not actually using >10A at the moment.
If I fiddle with these again I may try a C16 for the input and some sort of chassis mount BS1363 socket for the load
