I found this in 2 mins.

http://www.lazada.co.th/new-power-consumption-energy-watt-current-amps-voltmeterelectricitymonitor-analyzer-uk-plug-intl-39419490.html?spm=a2o4l.search.0.0.H7Zq50&ff=1

 

i am not sure if your sauna has a plug on the cable, you can buy them on amazon . You also purchase allot of other types of these types of power meter, some more expensive then the other. You can also buy a din mount KWh meter that you could put on the cabling somewhere if you are that way inclined.

http://www.lazada.co.th/catalog/?q=kwh+meter

On 7/10/2017 at 2:53 PM, Crossy said:

 

Measure the supply voltage (don't forget to select AC Volts)

 

 

Wise words of someone who had a meter blown up in his face one too many times :)

 

Thank you for comments.  I took a look at ladaza thanks.

Pictures of Thai watthour meters (with electro-mechanical discs) I see have the Revolutions/kWh indicated on the faceplate.  Such as 400 rev/kWh. Perhaps the electronic ones have the pulses/kWh and a blinking LED.  With a known load, you can check the accuracy of the meter using a stopwatch and counting revolutions/pulses for a set time. Or just calculate the consumption or load of a single appliance.  It's explained toward the bottom of this page:  http://www.pages.drexel.edu/~jef22/myweb4/eleccalc.htm

 

In the US, meters are marked with a Kh, indicating the Watthours per revolution of the disk. 7.2 Watthours/rev is common for residential service.  People used to do a rough test using a few 100 Watt incandescent lightbulbs as a load.

 

I watched a lot of meter discs spin during my 20+ year career in the electric metering industry in the US. Used to be a product/sales manager for a $40,000 electric meter test machine.