Shore Power Circuit Breaker Tripping Often

[rwidman]

Can you unplug the yard's power cord? Can you use a different power cord?


A breaker shouldn't fail because of a loose or intermittent power cord. Things like this are pretty normal.

[smac999]

A issue in a shore cord would trip the yard breaker not the boat breaker...

[SeeMonstrEd]

Check to make sure the wires to the reverse polarity indicator are connected. I had work done on mine and found out later the tech didn't bother to connect it. So you may have a short without the indicator.

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[Morganministry]

A couple thoughts. If the sheds polarity is reversed, this could mess with your system. Also depending on how sensitive your breaker is, loosing the ground on the yard side might trip it also. This would make more sense if they wiggle the wires and it starts working. There is a gadget you can pick up at a hardware store and plug into a regular wall outlet that will tell you if the polarity is reversed, the ground is bad, or if the neutral leg is being dropped.

[Mistress Sirena]

sound thinking !

[Mistress Sirena]

Make sure you are on the same phase 3 phase can be tricky

[masonc]

Originally Posted by Mistress Sirena

Make sure you are on the same phase 3 phase can be tricky

Same phase as what?

[PuttingDoctor]

Here at my marina I had a trip and the staff electrician found a loose neutral in the dock box.

[masonc]

Electrician here.If the power you are using is 240v three wire (120-N-120) which is standard US residential power, and you have a heavy 120v load, you may have a neutral problem. When the neutral connection is high resistance, the heavy load will push the neutral potential awsy from ground potential. This could result on high voltages on the other leg and high current on the first leg. That can trip your breaker. Have the yard check the neutral connection and check the voltage between legs and neutral while applying heavy load. This fault can damage equipment by overvoltage so you need to address it soon. It will not affect 240v equipment.

[Cadence]

Ray, are you reading the good voltage while connected up and under load? It sounds a lot like line drop causing excessive amps prior to your breaker. If moving supply cables makes a difference?

[foufou]

It must be that your off switch is not really off. How else could the breaker trip? So it seems to me there are at least two problems, and likely a third one at the yards power source. I have twice found wiring problems at different yards. One potentially very dangerous with hot and ground wires swapped!

[Sardean]

Ive seen this happen many times when water has got into Junction boxes or extension lead sockets, take the plug of, check for moisture, sometimes you can see black trails that the electricity was following these must be removed by scraping, reconnect plugs, should work. Ive also seen this problem when the sheath of a cable is broken and water shorts across cables this is not as common.

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[mitiempo]

Originally Posted by foufou

It must be that your off switch is not really off. How else could the breaker trip? So it seems to me there are at least two problems, and likely a third one at the yards power source. I have twice found wiring problems at different yards. One potentially very dangerous with hot and ground wires swapped!

The op has an ELCI. Basically a whole boat GFCI, set to trip if there is 30 mA difference between hot and neutral. Plugged into iffy yard power and wiring I would think that there could easily be an imbalance between hot and neutral large enough to trip the ELCI.

[Hudsonsailor]

Okay 1st thing you can do
with the power disconnected Check all connections
Where your plug attaches to your boat
where those three wires connect to you fuse box or circuit breaker
where your ac out lets around the boat
A loose cable at any one of these places will generate heat and draw enough current to trip circuit breaker
the fact that it doesn't happen immediately indicates a heat problem.
shaking the wires fix was probably incidental

[mitiempo]

Originally Posted by Hudsonsailor

Okay 1st thing you can do
with the power disconnected Check all connections
Where your plug attaches to your boat
where those three wires connect to you fuse box or circuit breaker
where your ac out lets around the boat
A loose cable at any one of these places will generate heat and draw enough current to trip circuit breaker
the fact that it doesn't happen immediately indicates a heat problem.
shaking the wires fix was probably incidental

Not with the main breaker off can these interior items cause it to trip.