Help with order for new install - US

Hello everyone,
I am ready to place an order, finally IoTaWatt in stock , Yay!!

Can i monitor mains with this setup & if how?
It seems CT clamps have to be installed in utility box above?


Thank you!

I don’t see any way to monitor the mains inside the panel. You would need to try to get an electrician to mount the CTs inside the meter box. That involves having the utility reseal the meter. Whether that’s possible is up to your loacl codes jurisdiction, the utility and the electrician.

An alternative would be to just measure all of the individual circuits. You can then define an IoTaWatt output that is the sum of all the loads. Users who measure al;l the loads and the mains have reported pretty good agreement.

You have 18 breakers, so some consolidation would be needed. I can see that the Tesla Charger is two-wire so that only needs one CT. I can’t tell if the inverter1 is two-wire, but they usually are, so that’s another single CT. Inverter2 is two-wire so there’s another. Now you only need to combine two other circuits, probably a couple of the 120V circuits on the right.

You wouldn’t need mains CTs, but ordering the NA bundle with two 100A would work because you need 4 100A for the two sub-panel feeds.

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Thank you!
this is my thought process and maybe i am wrong (please correct me), I have 2 Inverters and the reason i want to monitor the mains is to see how much power i am sending to the utility company.

Both inverters are two-wire

I do have 2 breakers for charging the cars, one is NEMA 15-40 and one you noticed, Tesla Charger.

For 2 subpanels - i thought i would need 1 x 100A for each, but it seems i am wrong

You would be able to create an output for that. You would add all of the consumption circuits and subtract the inverter outputs. Negative value would be export, positive would be grid usage. IoTaWatt now has a new feature to accumulate the total import and export.

An output that adds all of the consumption circuits would be your usage, independent of where it comes from (grid or solar). An output that adds the two inverters would be your total solar generation. In short, you can develop all of the metrics as a panel with mains CTs.

The subpanels would be three-wire, so can have an iombalance of 120V loads, hence the need for a CT on each of the 120V legs.

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That makes sense, thanks so much!

90%+ of the house goes to sub panels. Those 20Amps in main are various random outlets in the garage. Is it possible to combine those into single CT?

Yes, but the black and red must go through the CT in opposite directions.

Can you please confirm if my shopping list is correct:

2 subpanels (70A)- 4 x AccuCT 100A x 16mm split-core
2 inverters - 2 x AccuCT 50A x 10mm split-core
Tesla Charger (60A) - 1 x AccuCT 100A x 16mm split-core
Nema 15-40 (50A) - 1 x AccuCT 50A x 10mm split-core
2 x 20Amp breakers (40A) Left side - 1 AccuCT 50A x 10mm split-core
2 x 20Amp breakers (40A) Right side - 1 AccuCT 50A x 10mm split-core
2 x 20Amp breakers (40A) Right side - 1 AccuCT 50A x 10mm split-core

does this sound right? 12 breakers and 12 CT clamps

thanks again for your help and guidance

That’s how it looks, and if you should ever get access to the mains, you will have two spare inputs to add mains CTs

Thanks & since my panel is 200Amps and i have 2 wires coming from utility, i would use 2 x AccuCT 100A x 16mm split-core?

For the mains, if you could access, you would use 2x 200A.

Thanks! should i get the Current Transformer 200A x 25mm clamp-on or AccuCT 200A x 25mm split-core?

As these would be for if and when you can get them installed in the meter box, I would say the split-core.