### Three phase - sum apparent power from different phases

Hello all,

On three-phases-system, I'm using EmonTXs powered by USB with the main sketch (EmonTX Discrete sampling sketch) to get the apparent power.

Does it make sense to put several cables from different phases through the same CT to sum their apparent power ?

Eric

### Re: Three phase - sum apparent power from different phases

No. The summing will be done inside the magnetics of the CT, and you will measure the current that is the vector sum of the three currents. If the load is perfectly balanced across the phases, which in an ideal world it will be, the vector sum is zero. In the real world, it's the same as the neutral current.

So if you have 25 A, 10 A & 20 A on the three phases, the vector sum current you measure is 13.23 A. Not the answer you were looking for.

### Re: Three phase - sum apparent power from different phases

This is what I was suspecting... but I was not sure.

Thank you Robert for clarifying this.

Eric

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