Electric problems on a Mainship 390

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Paul Baker

Member
Joined
Feb 23, 2017
Messages
18
Location
United States
Vessel Name
Odyssea
Vessel Make
Mainship 390
Does anybody know a good boat electrician in the Fort Lauderdale area?
I had an electrician look and he has no idea - I did most of the diagnosing myself.

Here is the issue. I have 2 30 amps coming from a 50 amp shore power.
I used to have AC1 and AC2 power on the boat.
Last week something went wrong.
I have no power coming into the boat electric panel on AC2. (The electrician proved that much).
There is power coming to the boat (Again proved by the electrician).
So to run things off AC2 I have to switch AC2 to generator (Without the generator on).
Its as if the power consumed from AC2 then pulls from AC1.
I did switch around the input to the boat and same results.
Hence need for an electrician that understands boats :)
Any recommendations or suggestions would be awesome!
 
How about the breaker for the side AC2 that is not working?
Do the AC1 and AC2 breakers turn off either shore or gen power?
How is the selection of either shore or gen selected?
Both your gen and the shore power are a source for AC! and AC2.

What your saying is the gen can power both AC1 and AC2.
On my boat, the gen has its own separate 60 amp breaker, and the two 30 amp shore inlets each have their own 30 amp breaker.

The gen simply connects both shore as one circuit.
 
Last edited:
Correct. The breaker for AC2 is not working.
I can switch AC1 and AC2 on and off.
They are on a toggle which does not allow me to have AC and generator on at the same time.
When we open the electric panel on the boat there is no power coming into the AC2 breaker. But there is power coming into the boat. It's seems like the problem is between where power is connected to the boat and the boats electric panel.
I did swap around the inputs to the boat as well, same issue.
So in summary. AC1 works, AC2 does not work. When I move the switch to generator, the AC2 things like battery charger pulls the power from AC1 - as you say, the gen connects both shore as 1 circuit.
 
Correct. The breaker for AC2 is not working.
I can switch AC1 and AC2 on and off.
They are on a toggle which does not allow me to have AC and generator on at the same time.
When we open the electric panel on the boat there is no power coming into the AC2 breaker. But there is power coming into the boat. It's seems like the problem is between where power is connected to the boat and the boats electric panel.
I did swap around the inputs to the boat as well, same issue.
So in summary. AC1 works, AC2 does not work. When I move the switch to generator, the AC2 things like battery charger pulls the power from AC1 - as you say, the gen connects both shore as 1 circuit.

So the problem seems either AC2 breaker is bad, or the wire coming from the shore inlet AC2 is bad. If you can access that breaker, with a digital meter, see if it has power from black to white (hot to neutral).

And also check the shore power inlet for a bad connection, as in unscrew and pull it out and look into where the wires connect into the inlet. You may have a burnt or loose connection. A digital meter is easy to use for troubleshooting this.
 
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