1988 390 power problem

[larry w p]

I have 2 30amp connections,when plugged in everything works great.If line 1 or line 2 gets
disconnected it causes the main breaker to operate for the opposite line.This just started happening last boating season.If I am in a marina with only 1 30 amp outlet available the main breaker keeps operating.I have interchanged the shore power cords but no change.I have tried both direct 30amp connection and using 50 amp splitter but breaker still operate.
Any suggestions??

 

[hottoddie]

I'm a little confused of how you use the word "operate". Are you saying the breaker is "tripping"? Does this also happen when you run the generator?

 

[larry w p]

Sorry
Yes i mean tripping,and no this does not happen when using the generator

 

[hottoddie]

That would make the source of shore power or the shore power cords suspect. Is this a boat that is new to you?

 

[larry w p]

Have had the boat for 15 years,just started late last season,happens at all marinas so that rules out a shore
power problem.I borrowed my neighbors power cords and it still happened so that rules out a cord prob.

 

[electricaldoctor]

Have you changed the position of your shore power switch?

 

[hottoddie]

The problem seems to be between the shore power receptacles on the side of the boat and the back of the AC panel in the salon. I would unfasten the shore power receptacles and inspect the connections and then remove the AC panel (with the shore power disconnected) and inspect the back of the shore power switch and wiring.

 

[larry w p]

Have you changed the position of your shore power switch?

I have changed it to line 1 and the breaker trips on line 1 same on line 2,thats with only one power cord
connected to line 1 or line 2

 

[larry w p]

The problem seems to be between the shore power receptacles on the side of the boat and the back of the AC panel in the salon. I would unfasten the shore power receptacles and inspect the connections and then remove the AC panel (with the shore power disconnected) and inspect the back of the shore power switch and wiring.

I will look there next,thanks for the tips

 

[DougLas]

If the system you are plugging into has been upgraded to the GFI unit? The GFI is sensitive to ground problems. The repair needs a electrician to check out the wiring on the boat. The subject matter here is how the ground is wired? What was done at the time the boat was built was to use a shared ground on some of the wiring. This causing the unit to trip the circuit breaker

 

[Sublimetime]

I have the same problem as orig post. If I plug into non gfi breakers, I have no problem. If I try to plug into any other combination/position of shore power cords, or back and forth between 1 or 2 ,, and there is a gfi breaker on shore power pole I get tripped breakers. I gave up and do not use gfi for shore power.

 

[larry w p]

problem found
3 years ago had new bigger speakers installed,larger hole cut for cockpit speaker.Ground wire for line 1 feed
was cut,once repaired all works perfect.