110 V electrical problem.-gctid352143

[Guest]

This one has me perplexed. A friend with a 3988 has an issue with his 110v power. When he's in his boathouse, he's blowing the 30 amp breaker on the shore power box. Its not tripping the breaker on the panel in the boat, and he doesn't particularly have a heavy load going through the panel. I'm guessing that there is a problem somewhere between the panel on the boat, through the connectors and cord, to the panel on the dock, perhaps a wire corroded at the plug in end...something like that. If it were on the boat, you'd think it would pop a boat breaker first, or even the 30 amp breaker on the boat.

Any thoughts?

[mmichellich]

Anything can happen. I once had a bad situation that did not trip a breaker on the boat, nor the dockside shore side power panel breaker but tripped the pier master breaker for about 30 boats. It only did this when a unique set of switches were set when going from gen set to shore power (with gen set off). Even with my EE background it took two days to trace it to a wire that had come off one breaker and was touching another breaker (due to a breaker connection that broke off). On the 47 power panel there are about 200 connections.

[JimMc]

A problem easily troubleshot with an AC Ammeter and a bit of testing.

The shore power breaker could be weak. Easily tested.

Don't disregard the shore power inlet and associated connectors.

[Guest]

courtjeste wrote:
This one has me perplexed. A friend with a 3988 has an issue with his 110v power. When he's in his boathouse, he's blowing the 30 amp breaker on the shore power box. Its not tripping the breaker on the panel in the boat, and he doesn't particularly have a heavy load going through the panel. I'm guessing that there is a problem somewhere between the panel on the boat, through the connectors and cord, to the panel on the dock, perhaps a wire corroded at the plug in end...something like that. If it were on the boat, you'd think it would pop a boat breaker first, or even the 30 amp breaker on the boat.

Any thoughts?

Is the breaker being tripped a GFI?

[ksanders]

JimMc wrote:
A problem easily troubleshot with an AC Ammeter and a bit of testing.

The shore power breaker could be weak. Easily tested.

Don't disregard the shore power inlet and associated connectors.

I'm with Jim on this one.

Use a current clamp to look at the acutal current.

[SuperiorDiver]

Had a similar issue on our 4087, shore breaker popping, not the breaker in boat breaker. Cause was a loose ground wire screw in the shore powerr plug.

[mmichellich]

courtjeste wrote:
This one has me perplexed. A friend with a 3988 has an issue with his 110v power. When he's in his boathouse, he's blowing the 30 amp breaker on the shore power box. Its not tripping the breaker on the panel in the boat, and he doesn't particularly have a heavy load going through the panel. I'm guessing that there is a problem somewhere between the panel on the boat, through the connectors and cord, to the panel on the dock, perhaps a wire corroded at the plug in end...something like that. If it were on the boat, you'd think it would pop a boat breaker first, or even the 30 amp breaker on the boat.

Any thoughts?

How warm are the shore power cord connections at the dock and boat? Has he tried plugging into a different shore power dock source? Does the 39 have multiple main breakers which then combine going to the shore power? If so, the combination could be more than the shore power can handle. My 47 has three 30 amp main breakers which can be combined, could draw up to 90 amps in a worst case scenario but are fed by a single 30 amp shore side breaker/cable.

[Shocking]

Assuming he has a generator, disconnect from shore, fire up the gen, and see if something trips. That should isolate between shore issue and boat issue.

If the breaker trip is instantaneous, sounds like a short circuit. If it's a delayed action, sounds like an over-current issue. If that's the case, then the meter testing like has been suggested is the way to go.

Good luck.

[Uncle_Bob]

Or plug into a different shore breaker and see if it pops.

[Guest]

If the shore power is only 15 amp, the 3988 could trip that circuit, depending what is turned on in the boat. For example, my inverter/ charger automatically draws close to 15 amps initially when turned on. It settles down after about 1/2 hour. Dip switch settings on the inverter can be adjusted for 15 amp power source, but generalkly 15 amp is not enough for the 3988. If shore power is 30 amp, it would be less likely, unless you have all electric heaters on, plus oven etc. If the shore power is 30 amp or more, and you are tripping out without much load, the power cord or electrical shore power GFI breaker are likely the problem. As stated above, an ammeter would help diagnose/isolate the problem

[efarrell]

Suggest you also clean the plug recepticals that invariably form a thin coat of rust over them preventing solid contact. Have seen this happen. Use a sand paper and make sure you have bright shiny brass contacts.

[Guest]

How many boats are connected to this "30amp" circuit probably a single line feeding four slips with boats all having electric heaters running for the winter.

[Guest]

Thank you all for the suggestions.

[HughfromOz]

I am not sure here whether the breaker keeps tripping out immediately as in a short circuit, or if it taking a while as in an overload, or again it could be tripping from earth fault from the residual current circuit breaker. In any case the circuit breaker on the marina will see the fault first and trip out. Start by plugging in the power but turn off all the circuits on the boat including the main switches, if it trips out here then the fault will usually be at the power inlet. If not then start switching on each circuit one at a time. If it eventually trips it will tell what circuit has the fault and trace the fault through from their.

Good luck with it

Hugh

[Guest]

I had a weak breaker on the dock before. My slip would blow, nothing else. new breaker all is well. I can run heat/air, water heater, frig, microwave, make coffee, make ice and run the lectrasan and not blow it now lol!