How far from CT's to IoTaWatt

I have 400 amp service split into two panels. But the split happens at an Auto Transfer Switch about 10 feet away from the panels.

So, do I put 400 amp rated CT’s on the mains at the transfer switch and run them to the IoTaWatt which would be installed at the panels? Are the lead wires long enough to reach?


Do i get two sets of 200 amp CT’s to install at the panels and somehow connect them together for the mains?

The CTs have leads about 5 feet long. The leads can be extended with simple headphone extensions..With two extensions you can measure mains with 400A CTs at the transfer switch. That would be the more economical way to do it.

That works too. Downside is that requires four inputs on the IotaWatt. You combine them by defining an output in the IotaWatt that adds them together. The upside is you would know how much power is being used in each panel.