Hello t84a! Welcome to our forums!
Thanks for the photo and the clear description of what you are looking to purchase!
Your photo does look like a typical 120/240 volt 3-wire US residential system. You have 2 hot wires (in this case both black) coming in at the top of your sub-panel. If you measured the voltage between these 2 wires you would get roughly 240 volts. If you measured the voltage from either of the hot wires to a neutral wire you would get roughly 120 volts. Your install will be very similar to the video you referenced:
https://www.youtube.com/watch?v=nvTTFxy_yQw
Here is additional information about 120/240 volt 3-wire systems:
https://help.ekmmetering.com/support/so ... v-metering
The items you are intending to buy look correct. I would double/triple check that the wires you want to install the CTs on are under 13mm in diameter (under 1/2"). Buying CTs that are too small to fit the wires you want to measure is one of the more common mistakes in ordering.
I would also consider buying 2 of the 1 amp Inline Fuse Holders. I would install these close to the voltage reference in the sub-panel. These will protect the voltage reference wires that feed your submeter.
If you are planning on submetering Water or Gas in the future I would consider the Omnimeter Pulse v.4, otherwise the Omnimeter II v.3 UL will work well for your needs.
With the Omnimeter II v.3 UL connected as a read off the face (not connected to a computer) you will be able to keep track of how much energy is moving through this subpanel over time. You have the option to add connectivity to a computer or to the internet at a later date.
Hope this helps. Let us know if you have any questions.
