Similar to the other thread about a single phase energy meter, i’ve ordered one of this to test.
At the price of $34 it seems great 
Anyone played with this kind of meters already?
Just received this one.
Here are some photos of its insides.
Unfortunately i will be going out for vacations by the weekend so will have to test at an other time.
By the way, the internal CTs are rated to 5A max. But you can plug in external CTs (on the loop that goes inside the original CTs) and configure a divisor.
Anyone knows the math to select an external CT and what kind of cts are required, must have burden resistor or not?
If you use a standard 5 A secondary for the external c.t, then the internal c.t is the burden for the external one, and the ratio is simply the combined ratio. (So with a 250:5 external c.t., the meter reads to 250 A instead of 5 A. Presumably, you can alter the scale factor for the display to suit.