Has anyone connected two CT clamps in parallel to monitor total currents from two main breakers? e.g. 2 main service lines that split into 2 200A circuits. Connect each 200A CT clamp to Phase A of both 200A circuits, then combine the CT clamps with a Y splitter and connect to Phase A of the energy monitor port. In theory, the total current of Phase A should be the sum of the measured current from both CT clamps, right?
Are you saying wire the two clamps together in to one measuring port? As if so that will not work correctly unless I am misunderstanding.
The current clamps convert the measured current flow to voltage and as such if you wire them together the voltage will simply read the higher of the two measurements.
I think your description is incorrect, as you’re always connecting to phase A.
I suppose that you have Pout1 and Pout2 connected each to one of your clamps and connected to the load and then Pin1 and Pin2 combined into Pin and then connected to your mains P.
In that case, each clamp will measure the current for each load, but the total RMS current can be different from the sum of the RMS currents when the loads do not have the same quality factor (voltage/current phase shift).
Connecting current transformers in parallel on both lines of a split phase system will result in ‘almost’ a complete cancellation of currents (Kirchhoff’s Current Law) since current is coming in one and out the other they will negate each other. BUT having two clamp-ons on each line is common but they must be separate sensors.
Did you try this, I honestly can’t see why this shouldn’t work as long as you maintain the polarity, if you out them in opposite directions they will cancel. But I. Theory they are 2 current sources and if you connect them in parallel they should sum to give a total.
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I dont believe this is correct, if you look at most current clamps they simply convert the measured current flow and convert / report it as a voltage.
So if you had 2 clamps connected to two different circuits, producing twoi different output but both connected in parallel, for example you may have 1v & 2v outputs, but you wont measure 3v you will simply get 2v as this is the higher reading of the two. You cant increase the voltage when in parallel.
I am interested in someone knowledgeable answering this question.
CT clamps do not output a voltage, as far as I am aware. They output a current that is proportional to the current passing through the CT clamp. In the device that measures the current, that current is passed through some resistance and the voltage across that resistance is proportional to the current generated by the CT clamp thanks to V=IR.
In theory, I would have thought that the current through one CT clamp will simply add to the current of the other CT clamp. Of course, this assumes that the two CT clamps are across the same phase, which is what the OP has indicated is the intention.
Has anyone tried this or actually knows if it would work?
If you have two mains service lines, they aren’t necessarily on the same phase.
I think that you need to put them in series not in parallel. The voltages produced would then be added and this is what is sensed. It probably wouldn’t be terribly accurate though.