GFCI at docks for boats

[RobertV]

We have a Hunter 356 and use shore power while at the dock. The 30 amp circuit breaker has worked great with no trips or surging for almost 1 year. The boat has an indicator for ground and galvanic isolator conditions and both have been in the green "Normal" range. If there were an issue, it would flash and beep "Fail" We also have an after market charger/inverter on board.

We have been told we need to replace the 30 Amp breaker with a GFCI. We located a GFCI breaker compatible with a "Homeline" breaker box. We found a Cutler-Hammer 30 Amp GFCI (with a 5mA interruption limit for tripping). When I installed the GFCI, the breaker immediately tripped when I plugged in the shore power cord. I tried to turn everything off (A/C main and D/C main) and it still tripped. I then switched off the main into the boat and it stayed on... Until I switched the main breaker to the boat back on. Then click...tripped again.

I think the 5mA might be too low of a cutoff and maybe a 10 or even 30mA cutoff might do the trick. My question is does anyone have any similar issues with GFCI supplying the dock plug tripping? I should also mention, there is another in our marina who put in the same GFCI and it works fine. His sailboat is much smaller and has fewer electronic systems.

 

[Benny17441]

GFCI circuit breakers are great for garages, bathrooms, hot tubs and wherever wet floors can meet electrical appliances but not necessarily for wooden docks over the water. We had a similar problem years ago and after trying unsuccessfully to locate the source of any stray current we opted to substitute the GFCI breaker with just a regular breaker. We did not think that the GFCI provided much protection at the dock to start with as the shorepower outlet rested on a dedicated circuit and the only thing that we plugged to it was the shorepower cord. Each circuit on the boat is protected by a GFCI breaker or outlet. Problem solved. Don't know who told you needed to replace the breaker but I would check his qualifications and experience. To be on the safe side we consulted a licensed electrician with ample experience in boat docks installations and he agreed with our risk assessment and change of the breaker.

 

[centerline]

GFCI circuit breakers are great for garages, bathrooms, hot tubs and wherever wet floors can meet electrical appliances but not necessarily for wooden docks over the water. We had a similar problem years ago and after trying unsuccessfully to locate the source of any stray current we opted to substitute the GFCI breaker with just a regular breaker. We did not think that the GFCI provided much protection at the dock to start with as the shorepower outlet rested on a dedicated circuit and the only thing that we plugged to it was the shorepower cord. Each circuit on the boat is protected by a GFCI breaker or outlet. Problem solved. Don't know who told you needed to replace the breaker but I would check his qualifications and experience. To be on the safe side we consulted a licensed electrician with ample experience in boat docks installations and he agreed with our risk assessment and change of the breaker.

I agree...
when we bought our boat, it had a couple GFCI outlets with a regular 30amp main breaker.
the surveyor we hired from A. Mazon told us that we would need to either replace the entire main breaker system, or install more GFCI outlets, or rewire what we have to pass ABYC... the port circuit was correct but the starboard circuit was not with one of the installed GFCI outlets not even working. (6 outlets total)

so I rewired the circuits with an independent GFCI at each outlet, which allows it only to trip if there is a problem, rather than the entire circuit.
this way its easier to know where the problem is, if one should arise.

independent GFCI's are much cheaper than replacing the entire main breaker, and safer in my opinion...

 

[Maine Sail]

If you are replacing your main breaker on your boats AC panel you will need an ELCI breaker not a GFCI. Electrical breakers for home use should not be used on a boat.. Blue Sea Systems sells marine ELCI's..

 

[Ron20324]

Just to clarify, you are replacing the breaker on the boat panel, not the dock one? And not the 30 just inboard of the shore power input?

 

[uncledom]

We have a Hunter 356 and use shore power while at the dock. The 30 amp circuit breaker has worked great with no trips or surging for almost 1 year. The boat has an indicator for ground and galvanic isolator conditions and both have been in the green "Normal" range. If there were an issue, it would flash and beep "Fail" We also have an after market charger/inverter on board. We have been told we need to replace the 30 Amp breaker with a GFCI. We located a GFCI breaker compatible with a "Homeline" breaker box. We found a Cutler-Hammer 30 Amp GFCI (with a 5mA interruption limit for tripping). When I installed the GFCI, the breaker immediately tripped when I plugged in the shore power cord. I tried to turn everything off (A/C main and D/C main) and it still tripped. I then switched off the main into the boat and it stayed on... Until I switched the main breaker to the boat back on. Then click...tripped again. I think the 5mA might be too low of a cutoff and maybe a 10 or even 30mA cutoff might do the trick. My question is does anyone have any similar issues with GFCI supplying the dock plug tripping? I should also mention, there is another in our marina who put in the same GFCI and it works fine. His sailboat is much smaller and has fewer electronic systems.

Is this your home panel feeding your boat at your dock? Is it wired right? The neutral to the shore power outlet must be connected to the gfci breaker neutral connection and the neutral wire on the gfci breaker must connect to the neutral buss. There is no" the CH breaker fit my Homeline panel" according to code. The panel has a list of approved breakers that can be put in and I'm pretty sure CH isn't on the list. That panel is actually manufactured by Square D for HOme Depot I believe. Hope this helped.

 

[Ken Cross]

Had this issue with a hot tub once

I found with a hot tub installation that the wires weren't twisted in the conduit. This caused inducted current into the static ground. Current in the cold wire is diminished by this thus causing the GFCI to trip. Ideally the main conductors (white and black) wires would be twisted, but not the static ground (green). Good luck finding a cord like that.

Ken

 

[RobertV]

We were requested to replace the breaker on the dock. The breaker just inside the boat past the in bound dock plug in is good. As far as I know the boat wiring is all up to snuff. As far as wiring the breaker switch in the panel, we wired the hot and neutral to the GFCI and the neutral pigtail to the neutral bar (correct per the wiring diagram. The CW brand breaker is the same size, shape and fits the panel. It is also what was recommended since Homeline did not have a single pole 30 Amp GFCI, only 2 pole.

Another sailboat (with less electrical systems on board) put in the same thing that we tried and it worked fine. It is not tripping when plugging in their boat. They were the ones who suggested the CW 30 Amp GFCI single pole breaker.

 

[woodster]

We were requested to replace the breaker on the dock. The breaker just inside the boat past the in bound dock plug in is good. As far as I know the boat wiring is all up to snuff. As far as wiring the breaker switch in the panel, we wired the hot and neutral to the GFCI and the neutral pigtail to the neutral bar (correct per the wiring diagram. The CW brand breaker is the same size, shape and fits the panel. It is also what was recommended since Homeline did not have a single pole 30 Amp GFCI, only 2 pole.

Another sailboat (with less electrical systems on board) put in the same thing that we tried and it worked fine. It is not tripping when plugging in their boat. They were the ones who suggested the CW 30 Amp GFCI single pole breaker.

who owns the dock..... if not you let them fix it..... that is not your equipment if you don't own it ...its their responsibility

 

[Charles Erwin]

Pedistal mounted GFIC devices are disfavored. Such arrangements mean each circuit on the boat is protected by two GFIC devices instead of one. Multiple GFIC devices per circuit lead to nuisance trips. This is common.

Who came up with this idea and can they explain why you should do this? By the way it is very unusual for a marina to require a tenant to pay for and install shore side electrical modification.

Charles

 

[centerline]

We were requested to replace the breaker on the dock.

Another sailboat (with less electrical systems on board) put in the same thing that we tried and it worked fine. It is not tripping when plugging in their boat. They were the ones who suggested the CW 30 Amp GFCI single pole breaker.

did the other boat plug into the marinas pedestal that you changed the circuit breaker in and are using? and if so, did it work ok?...

they may have it right at their pedestal, and their boat wiring may be perfect, but until they plug in to where you are plugging in to, so you can see the difference, there is no possible way to compare the two different locations that would have any indication where the problem may be with your boat and/or pedestal...

slip around and plug into their pedestal and see what happens, or have them come around to yours and plug in.... or both, so you can compare the differences.
as difficult as it is for some people to hear, you may find the problem is with your boat.

or... once you have confirmed your boat works fine at their connection, and they have problems at your pedestal, then its kind of up to the marina to make it right if you are paying for shore power in your monthly rental agreement.

the reality of it is, if you are installing something that has not been authorized on their property, if it ever becomes a problem you can be charged for them to repair it... or worse, if you cause damage to someone elses boat/equipment, you may get to see how good your insurance is...

 

[njlarry]

Stop the music! This is all as clear as mud.
What is a ELCI?
Also as I under stand it.....I am NOT an electrian...a GFIC, ground fault interruption circuit breaker only works if you are grounded. You are not grounded standing on a wood dock or fiberglass boat.
Other than a wiring fault, what does a GFIC do an a dock.
Confused.

 

[RobertV]

Thank you all for the info and advice. I can say that our marina is a HOA type setup. We each own both sides of the dock (floating home on downriver side and 40 X 12 space on the upriver side). We are responsible for our own power sources to our houses and upriver side areas from the breaker box out.

I am starting to look at it like the houses that are attached to the power from the dock boxes. The sailboat has it's own breakers and GFCI outlets just like our floating home. The floating homes do not have any 200 Amp GFCI breakers at the boxes to the homes. The outlet is hard attached on a post at the dock and only our ship to shore 30 Amp cord is attached. It is attached to the boat with a twist lock and outer threaded ring so is fixed in position. I just need to detach from the dock first always and never from the boat first.

I have replaced the original Homeline 30 Amp circuit breaker back into the Breaker box and it is back to working great. The monitor on the boat for "Ground and Galvanic Isolation" feedback is reading normal on both and not registering as a fault. I know it does register as a fault on the ground indicator when something is wired wrong.

I have also been pointed to looking into "electrical impedance" as a reason why the GFCI Breaker trips, additional GFCI on one line causing the trip and DC feedback from the battery system on board.

Than you all...

 

[centerline]

Thank you all for the info and advice. I can say that our marina is a HOA type setup. We each own both sides of the dock (floating home on downriver side and 40 X 12 space on the upriver side). We are responsible for our own power sources to our houses and upriver side areas from the breaker box out.

I am starting to look at it like the houses that are attached to the power from the dock boxes. The sailboat has it's own breakers and GFCI outlets just like our floating home. The floating homes do not have any 200 Amp GFCI breakers at the boxes to the homes. The outlet is hard attached on a post at the dock and only our ship to shore 30 Amp cord is attached. It is attached to the boat with a twist lock and outer threaded ring so is fixed in position. I just need to detach from the dock first always and never from the boat first.

I have replaced the original Homeline 30 Amp circuit breaker back into the Breaker box and it is back to working great. The monitor on the boat for "Ground and Galvanic Isolation" feedback is reading normal on both and not registering as a fault. I know it does register as a fault on the ground indicator when something is wired wrong.

I have also been pointed to looking into "electrical impedance" as a reason why the GFCI Breaker trips, additional GFCI on one line causing the trip and DC feedback from the battery system on board.

Than you all...

glad to see your back to normal.... its is a good possibility that the fault interrupter is faulty... its not unusual to get a new one that is set "too close the the edge" and will trip when you plug into it, or will not allow power to pass thru it at all/not able to be reset....

as common as it is that ive seen new gfci's fail, I will always buy at least one more than I need to complete the task.
if I need ten or more, I will buy a few extras.
its more common to get a bad one that is new and has never been installed, than it is to have one go bad after its been installed and has been working correctly... unless it gets tripped too many times.

 

[Charles Erwin]

GFIC function does not need any dedicated ground- the safety green.

And - if you grab the black and white a GFIC will not trip.

A GFIC trips when the amperage difference between black and white is 5ma. An ELCI trips around 30 ma difference.

The idea is if amps in (black) are greater than the amps returning (white) the device trips. So if amps going into your coffee maker via black are less than those returning via white, the device assumes some of the amps are going through you and returning via the water you are standing in which is in contact with seawater via your through hulls. Hence the device trips.

Charles

 

[centerline]

GFIC function does not need any dedicated ground- the safety green.

And - if you grab the black and white a GFIC will not trip.

A GFIC trips when the amperage difference between black and white is 5ma. An ELCI trips around 30 ma difference.

The idea is if amps in (black) are greater than the amps returning (white) the device trips. So if amps going into your coffee maker via black are less than those returning via white, the device assumes some of the amps are going through you and returning via the water you are standing in which is in contact with seawater via your through hulls. Hence the device trips.

Charles

in my boat, mine will trip whenever there is a short within the appliance itself, without the need for an external ground to seawater or other pathway. or so it seems. I had a heater short and it tripped it... replaced the heater and no more problems.
the main circuit is protected by the main breaker, but from the outlet to the appliance and back, it seems like the GFCI protects it.

im not sure if it works this way at home, but I assume it would...

EDIT... and so if im NOT standing in seawater, and I get in contact with the bare circuit, then im just going to be electrocuted??.... how is this safe unless we all boat around with the decks awash with water?

 

[Charles Erwin]

Yes. If the device causing the trip is shorted that means some return is occurring via safety green and not all via white. Since some return is via white and some via safety green the device trips.

 

[centerline]

I edited my previous post, but even though you say the GFCI only works between the white and black, your answer would lead one to believe that the system works better with a dedicated green, such as we need on our boats to be "approved"....

 

[Charles Erwin]

EDIT... and so if im NOT standing in seawater, and I get in contact with the bare circuit, then im just going to be electrocuted?

You betcha

Review http://m.ecmweb.com/content/how-gfcis-work

Charles

 

[centerline]

EDIT... and so if im NOT standing in seawater, and I get in contact with the bare circuit, then im just going to be electrocuted?

You betcha

Review http://m.ecmweb.com/content/how-gfcis-work

Charles

well that really makes them seem like a pointless item to have unless one was standing in their sinking boat while tied to the dock when plugged into shore power....

or doing the same away from the dock with the AC genset running..... stoopid people