Current transformer with multiple wires trough it...

[Externet]

Hello all.

Can a single current transformer CT be used to read total household consumption loads L in U.S.A. system with 2 branches (X, Y) and neutral N supply, by reversing the direction of one branch passing trough the CT ?
In other words, currents on several AC wires trough the same current transformer add/substract ?

 

[Easy peasy]

It depends on the phase relationship between X & Y

if they are in phase then the current at the output of the CT will be X minus Y ( as drawn )

if they are out of phase ( 180 deg ) - the CT output will be X plus Y

for other phase relationships the answer needs the cosine of the difference in phase to be taken into account as well as the rms value of each

 

[BradtheRad]

Neither the X or Y wire is easy to maneuver into a loop inside the breaker box. They're thick. Slack is minimal.
Seems to me two current detectors can be installed, then wired so that the two phases get added.
Or have two meters (one for each phase), with the benefit of telling you whether you have balanced usage for appliances on each phase.