# Trying to understand the watts totals of mains vs individual breakers

I was able to finally install iottawatt and have been running it for some months now. i calculate the totals Watts for the 2 mains and it is 99% close to the meter reading.
If i calculate the total Watts for all the breakers and try to match it to the Mains, i am off by 1/3. The totals are around 3x the totals of the breakers. what am i missing here ?
i have added my inputs, outputs, status and a graph showing total of all breakers against total of two mains below

for the graphs image

this is how i had setup my breaker and the CTs

Breaking this down, you have reconciled your mains to an independent standard, so going forward I think it’s safe to say that the mains measurement is correct and the problem is with your individual circuit measurements.

Your diagram suggests that you are combining multiple individual breakers into single inputs. There are several ways to do that, and a lot of opportunity to do it incorrectly. I suspect that is the problem.

Without clear pictures, I’m left to guess what you may have done incorrectly, so here goes:

If you read up on split-phase in the docs, you find that the votage phase alternates as you go down the rows of your panel. When passing multiple wires through a single CT, you have to pass all of the wites corresponding to one main in one direction, and all of the wires corresponding to the other main in the opposite direction. If you don’t get that right, the incorrect wires subtract from the total rather than add.

I don’t want to get into any specifics referencing your chart because I don’t believe the Breaker Port numbers are useful as some refer to 120V breakers and some refer to 240V breakers. I’ve not seen a panel where the manufacturer labels some of the slots individually and some collectively.

One simple way to tell which main corresponds to each of the wires is to check the voltage between the main breaker and the individual breaker. If it is zero then the individual corresponds to that main. If it is 240V the individual breaker corresponds to the other main.

You also have some 240V breakers. In particular you have the Wall-Oven, Dryer, AC/Bath Basement and Cooktop as individual 240V loads. Review the various approaches in the docs to handling those determining if they are two-wire or three-wire.