You may remember me from such fantastic debugging posts as Is It split-phase or 120V/208V “two-phase”?, where I discovered that I have two legs of a three-phase power system in my home.
One of my circuits is a two-leg (eg. 208V/240V) air conditioning compressor. Based upon the previous discussion, I thought that this circuit could be monitored with one CT and the phase-to-phase configuration in the IotaWatt. Here’s how I thought it would go:
- Install CT (an 50A ECS1050) on one leg of the circuit, keeping an eye on which phase (A or C for me) that I install it on
- Connect to IotaWatt
- Configure IotaWatt input with “Mains Phase”, selecting the option that had the right phases being used in this circuit
- The IotaWatt input would then report the total power used on both legs
So, I installed the CT on the side of the breaker that was Phase C, and then configured the AC input:
Resulting in these inputs:
Then I checked the power readings before the AC was turned on…
And then cranked the A/C. In February. In Canada.
The AC circuit reported only 236W, pf 0.32, while overall power usage on the mains jumped much more than that. (Other circuits also changed; furnace -> makes sense; bath_floor -> unrelated bad luck to confuse this.)
Did I configure this phase-to-phase input correctly, or, misunderstand it?