That helps, but didn’t exactly answer my question.
We have to put in a 277v to 120v transformer to create a 120v output for the USB power supply anyway… because in this case it’s easier than running conduit from another 120v panel.
Can I use the 120v->9v reference transformer in the 120v outlet, and then just “calibrate” it up to the 277v supply voltage?
Or do I have to use this alternative AX-27750-H 277v reference transformer?