Hello ,

I would like to solve this issue that happened to one of my energy meter. This meter using Double CT setup with CT800A/5 as primary CT clipped into copper busbar (main aircond line for the building).

Phase A: No Current, but voltage ok around 240V
Phase B: No Current, but voltage ok around 240V
Phase C: Voltage very low around 1.1V but current ok around 200+ A.

Do you have any thought on this?

Based on the same thought, you can also clamp Cta and Ctb in the same wire of Ctc and check whether the current reading of phase A and phase B are nearly the same with phase C .

Hi:
I think maybe you have inserted the wrong wire in the Uc.
Please do this test.

1 remove the wire in Uc.
2 connect the wire in Ua to the Uc (short the Ua and Uc by a wire)
3 check whether the voltage reading of Uc is nearly the same as Ua now.
if it is still not the same, please give us a photo and let me see it clearly that you have shorted the Ua and Uc successfully.