Not to try and confuse but H1, H2, H3 is high voltage transformer (power pole) inlet the high voltage side.
Low voltage to house or RV is combinatio of phases L1, L2, L3, and L0 (zero) for N neutral.
Small generators and small transformers downstream of a service drop have H1, H2. Then X1 and X2 on the low side.
Something tells me explaining this using diagrams would be better. The different designations prevents mistakes in identifying transformer taps.
With a tapped neutral transformer there "should be" no potential between neutral and earth ground.
I'd better stop while I'm behind...