A few questions

I have a few questions about this device and I hope you can help me:

1) Given that there are different current ratings for this device and they all cost the same, what is the advantage of using one over the other. I plan to use this for a typical household. Can I just go for the 100A model just to be on the safe side?

2) I plan on using this device in conjunction with the "2-Channel AC Voltage Monitoring Controller" and a Particle Photon. Do I just plug in the Photon in one of the devices and then connect the two devices with an I2C cable, or do I have to use an SI Adapter?

3) To measure the household current consumption, I suppose I have to clamp the sensor over the "live" wire coming out of the utility meter. Provided that the sensor is exclusively around  live wire, does the proximity of the neutral wire's magnetic field affect the readings? Those two wires are usually next to each other and run in parallel.

4) If I want to get the true power reading (basically what I think the utility company charges me for), do I simply multiply the current reading by the value reported by the voltage sensor? Apart from the individual voltage and current calibrations, is there anything else I should take into consideration?

Thank you.



1. All the boards are calibrated for a particular current range, so lets say you want to measure a 40A load then its better to use 50A rather than 50A. Yes, you can use 100A.

2. You will need an SI adapter.

3. No, it won't affect the readings. because the sensor will read the field from the wire its plugged in. the electric field has to make a complete circle around the sensor to make it work and we can make a complete circle only by passing a wire through it. 

4. To calculate the true power you will need the phase angle value.

true power = V*I*cos(q)

where q is the phase angle.

for restive loads the q is 0, so the cos(q) will be one.

that's why in pure resistive loads apparent power is equal to the true power.

the easiest way to calculate is to use a known load and calculate phase angle value and then use that value to calculate true power of your entire house.

Let me know if you have any other questions.



Savio M Sacco's picture

Thanks Bhaskar.

Would I be correct if I said that the phase angle varies during the day depending on what appliances are on at any one time?

In the future, do you plan on featuring a single device that integrates both high current and voltage measurements and that can take into account a varying phase angle? Just an idea.


Ideally, the phase angle should be calculated by using voltage and current sine waves.

Yes, we are working on solutions which will do all this on one board.


Savio M Sacco's picture

That's great news. Thanks!