Multiple 20/15A Circuits Through Single CT?

[Scooter133]

I have some Lighting Control Panels that I feed Multiple circuits to. I also have rooms with multiple Recept Circuits. I’d like to be able to monitor the group of circuits vs each one individually.  The most I’d have is 3x20A or 40x15A, and even then, they would not be maxed out.

This is a Panel where I have Multiple Circuits going through a single CT. Are there any issues doing this?

Picture of the whole panel.

[gbrendemuehl]

You need to make sure the combined circuits are on the same phase. The phases alternate by breaker position, so you can’t put the wires from two adjacent breakers through the same CT, since they are on different phases.

[emporiacs]

Thank you! This is correct.

Here’s how we explain it:

To monitor more than one circuit line using the same 50A CT, you need to be sure they are in the same phase of power, otherwise they will cancel each other out and you’ll have zero readings.

[Scooter133]

Thank you.   Yes. I needed to run the L2 loads through the CT backwards.   I got out my Amp Meter and Measured.

L1 Circuit is 3.0A
L2 Circuit is 1.1A
Both Circuits are 1.9A, this was also the case from the App with the CT.

So it’s Subtracting the L2 Circuit from the L1 Circuit. Which makes sense that if the voltage from L2 is inverted from the reference voltage of L1, L2 would be negative current in reference to the L1 voltage. I ran the circuit on L2 through the CT backwards and in the App I get the 4.1 result that I should.  I did this with several Circuits that I could not move to the same phase and all seem to be reporting the proper current through them.

[Scooter133]

This can be for a 240 Double Pole, or two Singles on different Phases that you want to monitor as one.

 

[Robaroni]

Isn’t that wrong? Adjacent breakers flip to the other phase.

[Scooter133]

Are you referring to that I have the different phrases going in opposite directions through the CT?

I’m not sure  how it determines the reference voltage to use for a CT, seems to always Be ‘A’  so ‘B’ is 180 out of sync from ‘A’ so if you put them though the CT in the same direction it will Subtract ‘B’ from ‘A’  If you put ‘B’ through the CT backwards, its then going in the same direction (flipped 180) though the CT as ‘A’

I also verified with my AMP Meter.

[emporiacs]

Hi all,

Unfortunately, right now, the Emporia App does not offer a way of adding circuits together. It’s a very common feature requested by our customers, and we’re working on that to be launched in a future firmware update, but we still don’t have an ETA for that functionality.

As a workaround, you can export the CSV files and add the fields together to have the total for your appliance.

Sorry for the inconvenience.

More information: https://help.emporiaenergy.com/hc/en-us/articles/9556368100631-Combining-measurements-

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