[RESOLVED] Looking to Setup IoTaWatt

I’m looking to buy an IoTaWatt North American Bundle and I was just hoping to get some advice.

I have 2 questions that would help me in selecting the appropriate CT’s.

Mains CT’s

I have 100A service at my house but we’re thinking of upgrading to 200A in the future.

Should I buy 2 of the 200A CT’s for my mains, or would 200A CT’s not get accurate readings when hooked-up to my current 100A mains?
Who knows, I may never get around to upgrading our panel from 100A to 200A.

Bundling/Grouping Lines in CT’s

I was just hoping to get some confirmation if I understand how to bundle wires within a single CT.

As I understand it:
1) You can put multiple wires within a single CT, as long as the CT is rated to handle the combined AMPs of the lines.
So If I have 2 20A circuits, on the same pole, I could run both of those wires through a 50A CT and it should show the combined usage.
Similarly, if those 2 20A circuits are on opposite poles, then I’d have to run 1 of the wires 1 direction through the CT and the 2nd wire the opposite direction through the same CT.

2) If I have a 40A 240V breaker (dual pole), I can run both wires through a single CT, reversing the direction of 1 of the wires, to capture the entire usage.
Would this 1 CT need to be have 40A capacity or 80A?

I would want to do this for my 40A breaker that goes to my garage sub-panel which has several 15A and a few 20A breakers within it.
I just want to capture the entire usage of my garage from my main panel though.

I recently installed Home Assistant and have been setting it up to handle as much home automation as I can.
I’m planning to follow this tutorial I found on the forum for integrating IoTaWatt with HA:

You will get accurate readings with either. The primary considerations are wire size (16mm 100A) and cost.

That’s all correct


Thanks for the very fast reply @overeasy

That’s great news, I think I know what I’ll be ordering now :slight_smile: