Correct connection of a service entry is rife with regulations. Lines L1, L2, L3. Lines to neutral, and neutral to earth ground are vital checks. Excessive neutral to earth ground voltage must be avoided. Up there, the utility must be consulted on this. I have seen differences up to 200 volts RMS. Campgrounds are sloppy about this. My facility down here was tiny. But the furthest site had a 20 volt difference. I raised hell with the CFE and they had to replace their pole transformer. Remember. This is a neutral to earth ground issue.
L1 L2 & L3 load balancing is another issue altogether. As Is the line balance into an+ RV 50-amp service.