This may be of interest to you:
I’ve not seen a 440V service. Where is it and is that the phase to neutral or phase to phase voltage? What do you want to measure, and is there a neutral conductor on the service? In the above installation, the mains are measured with three (pairs) of CTs and three transformers on the 277V phase to neutral circuits. However, there are some delta connected machines and transformers that are 480V. They are easily monitored using either three or two CTs. IoTaWatt can do derived for the phase-to-phase (480V).
So the more I know, and possibly a picture or line diagram, the better I can advise.