I have one, I cannot get it to working.
I connected 119 to 1a and 1b, 110 to 2a and 2b and 148 to 3a and 3b. when I do switch test it show 119 on 2a, 148 on 3a and 3b, and rest 1a,1b,2b are X.
I checked the voltage on on powers inseter output 1, its 18v, so there is no voltage drop...