Smart Socket / Plug (U.K.)

Hardware
#1

Hi all,

I have a fairly basic automation which lets me know when our washing machine / tumble dryer is finished using power monitoring from a smart device - it took a bit of trial and error at first as the washing machine would trip smart sockets - I guess due to the high power when the motor spin up started - in the end I got one of these wired in and it’s worked well for around 6 months - https://amzn.eu/d/4eFElJG

I’ve noticed in the last couple of days it’s unfortunately stoped working - it’s reporting back power consumption at 0.8w constantly - so i’m having to return - issue is item is now out of stock so left back looking.

Does anyone have any recommendations on hardware I can replace this with, i’m open to even a smart socket which measures power consumption or maybe a clamp over the cable would be more reliable in this use case? Am open to ideas basically!

Thanks
Marc

#2

I just have our washing machine plugged into a regular UK smart plug and its been the same 1 for the last 2 years (Amazon bought 13A rating)

1 Like
#3

Do you have any specifications? Like what is the maximum (rated) power/current draw of your machines for example?

A esp/pipico paired with a pzem004t v3 (max. 100A) and supercharge with esphome could do such task :rocket:

Advantage of this solution should be less power draw (no energized coil for the relay) beside not introducing any additional resistance :muscle:

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#4

Just use a regular decent quality smart plug that has power monitoring.

We have been using a smarthings plug on our washing machine for years without fault.

There is something to be said about buying quality well recognised devices when it comes to mains voltage.

2 Likes
#5

Thanks for the suggestions - not sure if it’s because it’s a dryer too (although rarely use that!) but I’ve not had much luck with smart plugs (did try brands such as tp link / smart things)

In the end I’ve gone for a Shelly EM and a clamp over the live wire which seems to be perfect and at the same time is probably the safest way as not touching the wiring it’s self.

1 Like
#6

Indeed. :trophy:

People tend to forget (or don’t know) that there a different types of electrical loads.

Only resistive loads have a power factor that equals 1. That could be a heating element for example - if it draws 13A - it does this permanently.

On the other hands there are inductive and capacitive loads were the power factor is typical lower than 1. That could be a electrical motor (like found in washing machines and dryers for example) - if that motor is rated 13A it actually does not permanently draw a current of 13A but alternates between drawing 0A and maybe the double of the rated current - 26A the other moment. In average that will lead to a current draw of 13A and many consumer power meters will even show this.

The reality can be different simply that the relays (typically rated for 16A) in the majority of the smart plugs (including the “decent” ones) might just not withstand the “abuse” over time and will probably fail at some point. :put_litter_in_its_place:

So non-contact power metering with coil/clamp is indeed the way to go here :rocket: