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Galvanic Isolator tripping new dock power pedestal

Discussion in 'Technical Discussion' started by CSkipR, Jan 5, 2019.

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  1. CSkipR

    CSkipR Member

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    This past weekend at St Aug City Marina (all new dock pedestals & wiring) when I plugged shore power into the pedestal it kept tripping the breaker. A number of boats were having this issue because of the new breakers in the pedestals. We spent the first night across the way at Marker 8 with no problems and no problems at home or any other marinas recently.
    Traced it down to the galvanic isolator which we disconnected so we could have shore power. Not sure why the GI is causing the problem or how to fix it or maybe replace it.
    Any thoughts or comments on this?
    Skip
  2. motoryachtlover

    motoryachtlover Member

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    Others with more knowledge will chime in, but I bet the problem is due to the new electrical code that requires a ground fault circuit breaker on the power pedestal. If that is the issue I am told that there is most likely a problem with the item that has been isolated (your galvanic isolater). Boat US had an article on it. It has proven to be an issue for a lot of boats. When I docked at Naples City Marina (new docks built to new code) they gave me a info sheet on the issue at check in. I don’t know if there is sensitivity of the GFCI breaker plays a role in the problem. I was expecting trouble at Naples and had no issues.
  3. Capt J

    Capt J Senior Member

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    GFCI breakers are VERY sensitive. They will trip over a leak measured in milliamps, very minute. That being said I have a lot of experience with them on Euro boats that have them for the shorepower inlet breaker on the boat. I've had them trip where the a/c drain pan was clogged on a unit and it didn't trip the breaker to the unit, but would trip the gfci breaker to the whole boat.

    You have a small leak somewhere, but right now your galvanic isolator is eating it. What I would recommend doing is reconnecting the galvanic isolator, then turning off ALL AC power breakers on the entire panel inside the boat, then connect to shorepower. If it trips, the galvanic isolator is bad. If not, turn on 1 breaker on the AC panel at a time and wait 30 seconds, until you get to the one that trips the shore power. Once you've isolated it to the piece of equipment that's doing it, you can decide how to fix it. A lot of times it's caused by an aged compressor on a refrigerator or ice maker or something of that nature (which is on it's way out anyways).
  4. Capt Ralph

    Capt Ralph Senior Member

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    Your galvanic isolator was disconnected and the green wire left not connected to anything?
    Not a good idea for safety reasons but that proves there is ACv current flowing out on your green wire.

    A problem we had on a customers boat years ago when this GFCI started, on-board his white and green ACv were strapped together. Some return current was returning on the green wire and tripping that d$%^ breaker.

    White and green should only be strapped while on the generator, open on shore power. Older installations do not switch this at the transfer switch.

    As Skippy J commented, AC and fridge compressors are notorious for leaking current on the green wire, old and new equipment.
    If your ACs are 220Vac and on a single pole breaker, you may still have problems trouble-shooting these.
  5. wdrzal

    wdrzal Senior Member

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    On many isolation transformers they isolate L1 & L2 and the neutral, but not the frame ground witch is the same as a neutral. In some instances Its usually just screwed to the isolation transformer case. Giving a straight path past the isolation transformer.
  6. Capt Ralph

    Capt Ralph Senior Member

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    Rite and wrong.
    When on dock power, the ground (ACv green wire) and the neutral (ACv white wire) should never touch on the boat. They are tied on the dock, not the boat. The green wire carries fault current only...
    When off the dock, running inverters or generator, now your dock service fault line in not available.
    Later model inverters have the availability of an internal relay to tie ACv green wire to the ships bonding where fault current flows to the water.
    Your generator may already have white and green wires (frame) strapped or switched at the transfer switch for fault current to flow to the water.

    The isolation transformer still uses the green wire for a fault current path back to the dock service.

    Bottom line, ACv white and green (frame) should never be tied together on a boat while on dock service.
  7. d_meister

    d_meister Member

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    Galvanic isolators are usually nothing more than a large diode that prevents DC current in the millivolt range from coming aboard the boat from the shore (other boats, really). The voltage drop of the diode could be sensed as an open ground by the Ground Fault Circuit Interrupter.
    CSkipR, when you say that you disconnected the galvanic isolator, did you connect the boat ground and shore ground wires together?
  8. cleanslate

    cleanslate Member

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    Another simple clear cut way of trouble shooting by Capt J, when you speak, I listen. Makes sense.
    But otherwise my head my head is already hurting when it comes to the world of electric, especially on boats.
  9. CSkipR

    CSkipR Member

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    Based on what the electrician said at the dock I believe Capt Ralph is correct on the problem. It seems when this GI was installed in 2005 it may have been wired with the ground and neutral together. Unfortunately I cannot check it out now because we are no longer at the marina but we did perform a check by turning off all the breakers and one on at a time. After checking all of these we went to the GI. When it was disconnected it was not by tying the ground and neutral together. Will keep everyone posted on the repair or replacement to the problem.
  10. Capt J

    Capt J Senior Member

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    It shouldn't be. Just the green should be broken and the GI should have been installed with green in and green out (or in between where the green was broken).
  11. Capt Ralph

    Capt Ralph Senior Member

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    Do you have the factory ACv schematic? Contact Paul Hall @ Hatteras and they will send you a set if you want it.
    That could help but I can come down and figure it out with or with out.
    ,rc
  12. d_meister

    d_meister Member

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    +1
  13. Capt Ralph

    Capt Ralph Senior Member

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    If the white is loose with the green from the dock power then fault AND 115Vac is returning thru the water. Not safe and divers nightmare. Don't let any divers under your boat until this is resolved.
  14. Capt Ralph

    Capt Ralph Senior Member

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    Skip
    You have a single 240v / 50A plug or dual 115Vac / 30A plugs?
  15. Capt J

    Capt J Senior Member

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    His boat was built with a single 240/50 amp. Only some 35s and 31' cabo's were built with 2-30 amp cords if memory serves me right and all of the 32's had a single 50', 38' and above had 50 amp cords.
  16. Capt Ralph

    Capt Ralph Senior Member

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    That's what I thought, but had to ask.
    That makes all easier.
  17. Capt Ralph

    Capt Ralph Senior Member

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    More on this just came to mind this morning.
    Usually, the service from the dock to a 240Vac on board isolation transformer does not include the white wire (neutral).
    The output of the isolator (designed like an Auto Transformer) creates the white wire tap for ships use.

    If Skip has an isolation transformer, there should be no white wire connected to his galvanic isolator.
    Hey Skip, do you have a big white Charles Box on board?
  18. CSkipR

    CSkipR Member

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    No I don't have that. I have a ProSafe Zinc Saver 60 and a ProMariner Pro Safe1 GI monitor. The electrician went inside the ProMariner Monitor and disconnected a blue and brown wire from the breaker and no more tripping of pedestal breaker. Today, I replaced the blue and brown wires that he had disconnected and the monitor lights are back on & green. As I mentioned before this has only happened at this marina with the new pedestals. Everywhere else fine incl home dock. No issues with the diver cleaning the boat. I will get the electrician back out here but he believed it was the way the GI was originally wired.
  19. Capt Ralph

    Capt Ralph Senior Member

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    Skip
    Bottom line, an ohm meter should show an open on the shore power male pins between white and green wires (neutral and ground). If there is any conductivity, you will trip all new marina breakers.
    Absolutely no voltage (ACv or DCv) over a test resistor (10+K should work) between these same points also.

    Per your post #18. If these are sensing wires (blue / brown) they may be causing enough noise to alarm & trip the shore service breaker.

    The wave of the future you have experienced. It's going to happen more often as marinas start using these new safety breakers.

    One marina in Jax has a current sense coil around your power pole green wire and not these fancy breakers.
    They give you till next noon to correct if they see any current on the green wire (recorded and reported on an office computer) or they kick you out.
  20. CSkipR

    CSkipR Member

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    Will do a continuity check tomorrow on the shore power plug between the ground and neutral. Yes it is possible the blue or brown wire maybe causing enough noise to trip the marina breaker since he removed them and we didn't have the problem again.

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