I am trying to control a 3/4 horsepower pump for a pond via Insteon. I assumed that the circuit was 240V but when I checked with a multimeter it is just 120V. The breaker that controls the circuit appears to be a 20 Amp GFCI tandem breaker. I had purchased an Insteon 240Amp Load Controller to control the circuit given I figured I should get an Insteon device that could handle higher amperage: Please see wiring for the Insteon 240V load controller in the document at this link:
When I checked voltages on the breaker I noticed that there are 3 wires coming from the breaker. (see picture) There is a 120V line (Black Wire #1) and a White wire #3 going to Neutral bar. There is also another white wire #2 that I am unsure as to what it is. It is zero volts relative to ground when the circuit is active. When I press the “Test” button on the GFCI breaker the breaker trips and turns off the circuit.
Can I use the Insteon 240V Load controller for this application even though it appears to be 120V?
How should I wire it? What do I do with the white Wire #2 I described above?