[Solved] Why can’t the circuit breaker interrupt this circuit?

Claudio Saspinski Asks: Why can’t the circuit breaker interrupt this circuit?
I have a 3-phase input in my home. There is 127 V between any of the phases and neutral, and 220 V between any pair of phases. The electrical appliances have 127 V, and the wirings are such that the air conditioners (that uses higher currents) of 3 rooms are connected to different phases.

I replaced one of them, and the new one needs 220V. I used the phase of the old one and another phase used for the lights and sockets of the same room (see picture).

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It is working fine for some years, except that if I turn off the circuit breaker of one of the phases of the room (that used for lights), I have all kinds of unstabilities like blinking lights and beeping sounds from appliances. I need to turn off both S and T to properly turn off the energy of the room.

If only phase T is off, the sockets keep live. A voltimeter measures 127 V between live and neutral in the sockets. But an incandescent test lamp shines weakly as the voltage were smaller than that.

I suppose that somehow the phase S partially feeds T through the air conditioner wirings, but on the other hand, if the 2 phases were connected inside it, there would have a short circuit. There is a remote control for the air conditioner, and I don’t turn it on during the experiment.

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