And got them installed in a box through my electricity guy for times like this. They do not last for long though. After a few months, they tend to show incorrect figures. So I keep them off and only turn them on when power supply appears to be wonky. Instantly tells me the quality of power in the three lines coming into the house.
And we have a box where I can rotate a switch to change phases. So when power supply goes crazy, I just switch entire house's supply to the supply which has proper supply. I don't know what this box is called.
As you can see here, since blue had proper supply, all of these are pointed at blue. Otherwise, I have these three pointing at the three different lines.
Not sure if phase is the right word for these supply lines. Googling tells me three phase supply means something completely different. @vedantlath might be able to elaborate.