Low shore power voltage

Which mArinas ? Are we taking out of the way, small places in the boonies whe they rarely see a big boat or active east coast places? Have you talked to dock neighbors?

Anything below 200v and I go to generator.

And you left Cape May?

I'm afraid your the victim of everybody wants A/C, your at the end of the dock, budget designed the electrical system at the dock your at and your at the bottom of the scrodem pole.
Unfortunately, the marina / docks believe the house is in there favor and there rite.
$8 to $9 is the premium rate down here with Y transformers and no less than 208vac.

I've also had to balance a dual 120vac boat service. Used 240vac service but NO 240vac equipment on board. Had all the A/C equipment (four and pump) on one 120vac line and the fridge, charger and rest of boat on the other 120vac line. I mover one of the A/C set to the other leg and the dock breaker stopped tripping.
Do you have an unbalanced leg? Maybe a charger or ice maker you can turn off? Need that water heater?

Or, as I have said before, keep shopping till you find a better built dock.

U still hobbling around or skipping along yet?

Good luck

When you only get the 175V instead of 220-240V but your two 120V legs are 110-120V it's not the power company. It's the marina not having the proper transformers. If you 120V outlets are putting out 90V then it is the power company / load on the system.

On another note - Is there a website that rates the electric available at marinas? It certainly would make a difference for some cruisers to know that they can stay at marina A AND have air conditioning or marina B and not have it. Also might help to motivate those with poor power to correct it.

Was in Cape Charles (Kings Creek marina) over the weekend. Single 50 ~240V no problem. My buddy's 90' 100 Amp no problem. However two other 70-90'ers were both running their generators to supplement shore power. The marina did have an electrician working on the problem.

Active captain... You can comment on marinas service there for all to see

Yup.

The problem is the way the power is delivered and used. The power coming from the "problem" marina's is a nominal 208V from 2 out of the 3 phase power coming to the marina. Right away this may cause a problem because the three phase is no longer balanced and may be severely unbalanced. On some boats it then goes through an isolation transformer which creates the new ground/neutral tap. This, in theory, will give you 208/104 in the boat. For whatever reason the isolation transformers in these boats don't do a good job of converting the 120 degree phase power to 180 degree power and you will typically lose 10% of the voltage. If you have a 3 wire 240V power cord this definitely applies to you.

When the boat is connected to a proper transformer of 120/240V everything works fine.

Since the isolation transformer is part of the ground protection for the boat you can't just bypass it. Some of them had a set of taps for boosting European voltage to US. In these boats it is possible to wire in a input source selector switch which will use the boost taps on one setting and the regular taps on the other setting.

As NYC has found out this issue is something akin to black magic to most electricians. This is not a problem you have unless you are moving from power supply to power supply. When 240V single phase is needed they would simply install the correct transformer instead of using 2/3 of the 3 phase. It seems some of marinas just use the 208V/3ph supplied by the power company. Small problem without an isolation transformer. Bigger problem with one. I hope I've relayed this properly. I am not an electrician but I did get the information from a good friend who designs electrical systems for office buildings.