Cited as a reference · for some experience
The US electrical system is not 120V
Why people recommend it
Referenced for a detailed look at how American service panels are laid out and why 208 and 240 volt supplies differ.
Watch for: US wiring practice only
In their words
This video represents our standard layout (except the 240V breakers on that "QO" type have only a single handle, oddly.)*
Harper - Reinstate Monica on electronics.stackexchange.com, Feb 2022. CC BY-SA.