I’ve had my IoTaWatt hooked up to my breaker panel for about six months now and in general I’m very happy with it. Among the circuits I’m monitoring is our well pump. It’s a 220 volt circuit where I have a CT on one leg and double the reading for reporting. That should be sufficient since the circuit is not split phase. Suddenly about a few weeks ago it has taken to reporting 2-3 watts rather than 0 when the well pump is not running. At first I suspected the pump or the pressure switch, but even after I pull the breaker it still shows 2-3 watts at rest. Does this mean the CT is bad or needs to be recalibrated? Any other idea as to what might be going on?
As they say on some forums, “pictures or it didn’t happen”.
My Iotawatt shows about 0.5W when there is nothing connected or when there is no power being drawn. Doubled, that would be ~1W. That is normal.
You didn’t say which CT you are using. I am using ~50A CTs, which is what I suspect you are using. There are many different ones you could be using. You might have clamp on ones that are not fully closed.
I would remove the cable from the Iotawatt and see if the reading changes. I would swap channels to see if the problem moves or stays.
Sorry about the lack of details. Yes, I’m using the 50A CTs. I just disconnected the cable from the Iotawatt and it is still showing a baseline of 2 watts. Is there any way to recalibrate?
Maybe. With the CT unplugged, uncheck double and see if it goes back to zero. If so, it may be possible to install the CT in a different way that doesn’t use double.