I bought a pair of these and mounted them in their own box. Each hot has to pass THRU the current transformer sensor but the sensor can be opened so you don't have to disconnect any wires.

https://www.amazon.com/PZEM-011-Digital-Voltmeter-0-100A-Accuracy/dp/B08QN74TPD/ref=sr_1_2

Even if there was a way to do it with one, you would want 2 anyway so you can balance the load on the legs. The leads on the sensor are short (and flimsy) but you can extend them. To sense voltage (and to power the unit) you need another pair of wires between each hot and neutral. I have the thing mounted on my (indoor) generator inlet box, not the generator itself.