[jclark003]

Egstasea has it right and this is what I was trying to say before. all of the ac systems on your boat should be 120 vac. The 50A 240v supplies 2 legs of 120 that supply different parts of your distribution panel / electrical load. Your single 30 is bridged across both sides and should supply the entire panel (at reduced capacity). The meter is just telling you what is being supplied.

If you are in doubt reach out to Tiara and they will most likely send you a electrical schematic.

If you are very comfortable around ac you may want to meter the back of the panel. With the 50 cord attached you should see 2 120 v legs (providing the neutral is present). if you don't then work backwards to the pedestal. If you do have both legs then work your way out to the breakers. Obviously be careful in there.

If you are convinced it is the problem you should be able to verify neutral at the pedestal. One lead into l1 and one lead into neutral should show 120. If it shows 120 the neutral is good if not then you have your proof to the marina operator that something is wrong.