Measuring AC voltage

Hi all,

I have a need to measure the AC voltage coming into my apartment.

None of my Zwave or ZigBee outlets seem to report this properly, does anybody have any suggestion on how I can obtain this measurement ?

The 2 outlets I have that measure power also measure voltage.

Perhaps if you say which country you are in then people can suggest some options. Alternatively, you could try the Zigbee and Z-wave databases.

The Xiaomi I have does it.


The Tuya’s don’t (or not reliably, at least)

Kasa TP-Link and Tasmota plugs report voltage.

The plugs I’ve found that measure voltage and current only do so at at best 10’s of samples per minute. So if you are trying to capture short period voltage aberrations you will need a much more expensive device or build a custom A/D device that samples at a much higher rate. Good hunting!


Oh right! Im in AUstralia


Ive got some Xiaomi outlets around but none of them seem to report it :frowning:


Kasa could work, Do you know if HA can talk local to it or is it cloud only ?

@dproffer I dont need a high sample rate, I am just hoping for a high accuracy :slight_smile: I will be using it to perform power calculations

The TP-link integration is local.

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I’m not sure I am fully understanding your use case, however the any statement about high sample rate or high accuracy in conjunction with the USD 10 to 15 power monitoring plugs that we mostly use for home automation really do not align. Below is a link to some babble and tests I did a while back trying to get accurate real time power cost numbers, IHMO is it not really possible without spending a lot of money. If you want a statement of the problem/challenge, google ‘bang bang power’. This is how a significant number of home devices consume power and which makes measuring their real time usage difficult. The example I give shows that the measuring frequency and integration formula used can generate answers that vary from USD 0.07 to USD 3.1 per washing machine cycle. Good hunting, hope you find a useful solution for your use.


I dont need lab precision, but given the two devices I have that report it are on the same circuit near eachother, but often reporting over 10v difference between them, I dont trust them… I was hoping for something that other users have been using and that seems reliable enough.

I have a device that uses CT clamps to measure the current flowing through the 3 phases entering my home, but I dont have a voltage reference that I can use with this data to calculate the power usage properly.

I just am looking for either an off the shelf module I can hook up to an ESP32 to measure the voltage myself, or some smart switch type thing I can plug into the electrical box right by the clamps to get a decent measurement close to the input source.

I have 2 of these for the power coming into my house and am very happy with them.

Two of what?:eyes:


Thanks! I think this will work for me, Its a shame it only has one CT… 3 would mean it can do everything!
Ill order one and try it out, I grabbed a TP Link plug with energy monitoring too, so I can compare them.

I got a Tapo not a Kasa… It doesn’t report voltage :frowning: