Have a 52’ 1976 Stardust Cruiser Houseboat
Currently I have a 50 Amp connection from shore to boat. The marina wants to change to 30 Amp. What’s the easiest and best way to accommodate this (adapter)? I don’t want to move. Will I still be able to use 220 with my central heat?
You have two different things going on.
1. Yes, you can make an adapter from a 30A to 50A - in your case, you will need a 30A male to plug into the dock, connected with wire to a 50A female to have your cord plug into that.
2. To know what will happen at the outside breaker is also simple - does your heating draw 25-30 Amps? If so, you will be blowing the breaker. I suspect that 30 Amps will not be enough for your boat. Additionally, most 50’ dock slips have 50A because of this.
Lastly, your service is likely being cut from 220v to 110v