Shore Power Circuit Breaker Tripping Often

[FollowingCs]

Long story short:
1. One month ago, an electrician installed a Blue Sea Systems ELCI 50 Amp circuit breaker replacing the old 50 Amp breakers. All was fine for two weeks on pedestal power, until...
2. Two weeks ago we were hauled out for other repairs (shaft seals). When the yard first connected us to shore power (a somewhat questionable shed, not a pedestal), it faulted my inverter. So they wiggle some power cables, and it worked fine for a week+.
3. Last Friday, at 4:45pm of course, some other workers moved my power cables, specifically the connection between the two 50 Amp shore power cords. This blew my shore power circuit breaker. The yard manager tried to help us wiggle cables again, but it hasn't worked.
4. The circuit breaker can trip after 5 minutes, but usually lasts 20 to 30 minutes.
5. We swapped various cables and even the power socket. Same issue.
6. We can keep the power selector switch in the 'off' position and it still trips eventually, or we can charge the batteries and run the water heater.
7. We tried connecting a 15 Amp extension cord, to a 15-to-30 connector, and then a 30-to-50 connector, and it still trips eventually.
8. The yard claims to not have any problems with the power in this part of the yard, but we've heard different from other boaters.
9. And of course, the electrician who installed it is on vacation for 3 weeks.... ugh.

NOTE: This is not a ground fault trip. The red ground fault light is not on. this is a circuit breaker tripping. (It is a magnetic mechanism according to Blue Seas).

I don't think it is anything in the boat, because it trips when the selector is in the Off position.

It is either crappy shore power (non-pedistal, just a shed), which has not been right since hurricane Matthew (St. Augustine), but if that is the case why did it work for a week plus?

My fear is that the janky shore power connection and the workers jiggling the power cable somehow damaged my circuit breaker.

Thoughts, or not enough info?
Thanks,
Ray

[a64pilot]

What trips a circuit breaker is heat, what causes heat of course it pulling too much power through the breaker. Too much meaning in excess of it's rating, in your case more than 50 amps.

Your clearly not pulling more than 50 amps, only thing I can possibly think of is voltage too low, take your multi meter and measure your voltage, if you don't have one, now is your chance. I say buy a good one, I like the Fluke brand.

In truth I don't know, checking voltage is easy though and where I would begin

[senormechanico]

The OP stated it's a magnetic breaker.
What trips it is excessive current, not heat.
A breaker that depends on internal heat buildup can't react as fast to current overload as a magnetic design.

Make sure there's no phantom load, such as a space heater, hair dryer etc.

[FollowingCs]

Thanks for the reply. This is actually a magnetic-hydraulic circuit breaker, so not heat, but over-current in general.

The issue with measuring is that 'initially' it all measures just fine, between 118 Volts and 122 volts. And the breaker works for 5 to 45 minutes.

One electrician is saying it might be a loose connection, which could cause the time delay. I'm going to recheck things, but I don't see anything loose.

- Ray

[FollowingCs]

Originally Posted by senormechanico

Make sure there's no phantom load, such as a space heater, hair dryer etc.

Thanks for the reply. Any idea how a phantom load would occur if my Shore Power selector is 'off'? It trips even if Shore Power is "Off".

- Ray

[jstevens]

The Blue Sea ELCI should have a red and a green LED. One of those LEDs should be lit when the breaker trips. If the red LED is lit the breaker tripped due to a ground fault. If the green LED is lit it is an over-current situation.
Given the breaker trips when the power selector switch is off and wiggling the cords temporarily fixes the problem, it sounds more like a ground fault.
Of course I'm not an electrician, just a guy who has tripped a lot of breakers.

John

Ooops, missed your comment about the red LED not on

[DeepFrz]

What cables were wiggled?

Sounds like a bad ELCI or you have a serious short in your boat wiring prior to the shore power switch.

[FollowingCs]

Originally Posted by DeepFrz

What cables were wiggled?

Sounds like a bad ELCI or you have a serious short in your boat wiring prior to the shore power switch.

The shore power cables were wiggled. My 50 ft cord attaches to the yard's 50 foot cord. That is the part that was 'wiggled' to get it to work, and the part that was disturbed on Friday when the first trip happened.

I'm not sure how a serious short occurs all of the sudden, and then randomly occurs after 5 to 45 minutes f being connected to shore power. If it is a short in the boat prior to the power switch, it should short right away, shouldn't it? I don't get the intermittent part.


- Ray

[FollowingCs]

Originally Posted by jstevens

Ooops, missed your comment about the red LED not on

Yep, Blue Sea tech was ready to send out a ELCI test kit.. took me three times to tell him it's not the Red LED.

- Ray

[Scot McPherson]

Does your Main Breaker detect polarity reversal? That's what the red light means on my bluesea panel, which I wired myself so I know _exactly_ how it's wired.

It is possible, that tripping the circuit breaker due to arcing or power surging from "wiggling" the cables has destroyed the breaker's capability to operate properly. ALWAYS shut off your power breakers and switches before "wiggling" cables. You should open the breaker every time you connect or disconnect a power source or power draw in the case of a branch circuit.

Before you go to the hassle of troubleshooting your boat's circuitry, go buy another breaker. They aren't all that much money and chasing a circuit fault when there may not be one is a huge waste of your time. If you are still connected to that bad electrical source, I would disconnect from it and stay disconnected from it. Wait until you have a reliable source of clean electricity.

If the breaker is still a problem after replacing it and returning to a known clean source of electricity, then begin troubleshooting.

Have you disconnected your inverter? Does that change anything? When troubleshooting, ALWAYS reduce the system to the very basics. Disconnect _everything_, connect shore power...does it trip? Throw a branch circuit into the closed position...how about now? Add Another...and another. Nothing yet? Ok, now put a load on one of those circuits. Keep adding one thing at a time, wait the appropriate amount of time until the breaker trips....Ok....Now disconnect everything else, and leave only that item that tripped the breaker...does it trip the breaker now?

You get the picture...be logical about your steps so you can isolate the segment where the problem lies.

[rwidman]

Originally Posted by FollowingCs

..................One electrician is saying it might be a loose connection, which could cause the time delay.

A loose connection will cause heat (at the terminal) which will eventually trip the breaker.

You can't see loose connections, you have to put a screwdriver (or allen wrench in some cases) on the connector and try to tighten it. If it turns, it was loose. If you're not experienced at this, you might want to turn the power off first.

[rwidman]

Originally Posted by FollowingCs

The shore power cables were wiggled. My 50 ft cord attaches to the yard's 50 foot cord. That is the part that was 'wiggled' to get it to work, and the part that was disturbed on Friday when the first trip happened. ...............................

If you wiggle the wires at a particular place and it "fixes" the problem temporarily, That's the place to start looking. The yard's cord may have seen a lot of use and misuse.

[a64pilot]

Originally Posted by rwidman

A loose connection will cause heat (at the terminal) which will eventually trip the breaker.

You can't see loose connections, you have to put a screwdriver (or allen wrench in some cases) on the connector and try to tighten it. If it turns, it was loose. If you're not experienced at this, you might want to turn the power off first.

Sometimes this is an excellent use for a point and shoot IR thermometer, usually as you say loose means hot.
Just I don't understand it tripping with it not being connected, but I dont understand a shorepower switch, is this a switch you select say generator or shorepower? Why have a switch?

[FollowingCs]

Originally Posted by a64pilot

Sometimes this is an excellent use for a point and shoot IR thermometer, usually as you say loose means hot.
Just I don't understand it tripping with it not being connected, but I dont understand a shorepower switch, is this a switch you select say generator or shorepower? Why have a switch?

The switch has 3 positions. Shore Power, OFF, and Generator. The OFF position is supposed to disconnect the boat from power until you are sure it's all connected properly. Big issue in this fricken yard because we don't have access to turn off the breakers while messing with power cords. It's not a normal pedestal, I'm connecting to a power shack.

- Ray

[FollowingCs]

Originally Posted by Scot McPherson

It is possible, that tripping the circuit breaker due to arcing or power surging from "wiggling" the cables has destroyed the breaker's capability to operate properly. ALWAYS shut off your power breakers and switches before "wiggling" cables. You should open the breaker every time you connect or disconnect a power source or power draw in the case of a branch circuit.

Exactly! Big issue in this fricken yard because we don't have access to turn off the breakers while messing with power cords. It's not a normal pedestal, I'm connecting to a power shack. The power panel is a normal 'breaker' panel, unlabeled, and can't tell which breakers go with the various outlets. It kinda sucks. The yard manager is the guy wiggling cables while connected... I didn't like it when he did it...

Originally Posted by Scot McPherson

Before you go to the hassle of troubleshooting your boat's circuitry, go buy another breaker. They aren't all that much money and chasing a circuit fault when there may not be one is a huge waste of your time. If you are still connected to that bad electrical source, I would disconnect from it and stay disconnected from it. Wait until you have a reliable source of clean electricity.

Yep, I think I'm going to wait until I get back in the water hopefully next week, and then start troubleshooting. The electrician 'might' be back from vacation. On the hard in this yard just sucks, as I'm sure it does most yards. The new breaker/ELCI combo is like $330 unfortunately, so if it is damaged, it isn't just the 50 AMP breaker that needs replaced. I will argue that with the yard once I'm back in the water and ready to leave. Until then, I am hostage anyways.

- Ray