New IoTaWatt setup - CT's and other questions

Hi all,

I’ve been running an efergy engage hub for a few years, monitoring solar generation and grid usage (Australia). The hub has recently shat itself so it’s time for an upgrade. I’ve enclosed a pic of my single phase switch box.

A couple of questions -

I note that there is basically a choice (at least via of either 100A or 50A CT’s - so by my understanding I’d only need one 100A (for the main switch which is rated 63A) and the rest 50A CT’s ?

Next question, can I use one CT to measure both the airconditioner circuits (FAMILY/BED) - by putting both wires through the CT ? Total ratings for both circuits is 36A ?

So I’d need

1 x 100A
6 x 50A (wall oven, power, light, solar, aircond1/2, hotplates)

Any help, corrections or input gratefully accepted !

Pete M

Yes, that should all work.

1 Like

Thanks for that overeasy, much appreciated.

One other question, does the system integrate with any smart plugs? My circuit (apart from air conditioners / oven) doesn’t differentiate appliances such as dryers, washing machines etc, I’d be interested in integrating with smart plugs on some of the bigger appliances. I know I could use shelly devices for power monitoring, but unsure if any of those type devices integrate to keep the data in one place ?


IoTaWatt doesn’t accept data from other devices, but you can upload to a common database like influxDB or Emoncms. Both are open and have both OSD and cloud versions.

Dryers are usually on a dedicated circuit and washing machines usually don’t use enough energy to worry about.

Thanks again for your answer. I forgot about uploading to a common database, that won’t be a problem. I’ve never seen a dryer on it’s own circuit here in Oz…

Thanks again.


OK, so Iotawatt arrived Wednesday (thanks SmartGuys Australia, fantastic service)

Minor issue in setting up that has been mentioned before - I thought that I had a faulty unit because it would connect to wifi then disconnect. Turns out I had an inferior USB cable. So be sure to use high quality USB cable and power adapter. Once I got that sorted I haven’t had an issue.

Thursday I had a second solar install put in, taking me from 3.5 kw to 9.9 kw running via two inverters.

By Friday I had the following setup running via Emoncms. I’m also uploading to PVOutput.

Lots more playing to do but making good inroads. Now to teach the wife when to use the appliances - wish me luck.