6-wire house service - how many CTs

I am in US. House has 6 wires going into into 2 panels (1 of which has a sub-panel) - 3 wires into each panel. Will IoTaWatt work for this setup and how many CTs do i need to just measure whole-house usage>?

Most likely four, but a picture of each panel would resolve any doubt.



Thanks @overeasy - here is the pic. I assume thick black cables at the bottom is where power enters. 3 into each panel. House also has 2 30a generator outlets outside and each panel has an interlock so i am not 100% sure if these black cables run to the meter or to the outlets…

It looks like those are the mains. 30A doesn’t need such large cables. I think you can put 200A CTs on the red and black going into each panel. You can do it easily and safely right there in the wire trough that you have open.

@overeasy almost done with my project - thanks for help. could you please confirm that following things are true:

A. Total house consumption = left red + left black + right red + right left (i.e. 2 clamps on each of the 3-wire panels) - see pics above.

B. If I want to measure current from a double-breaker I need 2 clamps? For example I have a breakers for the dock (100A) it has 2 conductors - i currently have 2 clamps for each of the conductors - is that the way to set it up?

C. Is that also true for regular 3-wire circuit? Or can i just measure load on 1 wire?

D. I can add 3.5mm jack to AcuCT-40 and AcuCT-100 by soldering leads to sheath and tip. It seems to work but I want to double-check. i bought some on acuct website cause yours was out of stock.

right black, true.

There’s more to it than that. C’mon folks, please read the documentation about CTs and 240V split-phase.

Well, I’ve never been out of stock on those, but whatever. It is tip and sleeve. I hope you got the right configuration. Most of the offerings are 333mV output rather than 50mA required by IoTaWatt.

@overeasy thanks for split-phase reference. I thought initially that it’s some sort of rare setup but it looks like most North American homes use it. Read up on it.

Yes. These are 333mA. Are they usable? I tried to specify needed count of CTs when ordering iotawatt initially but it would only allow me to do 2 per kind I even had to order different kinds. Anyhow - anyway I can use these 333mA?

I’m afraid not. Ebay.