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Foreign Wiring & Electrolysis

Discussion in 'Technical Discussion' started by Seasmaster, Sep 10, 2019 at 9:34 AM.

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  1. Seasmaster

    Seasmaster Senior Member

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    Requesting help from all those electrical guys about wire colors in foreign (Dutch) boats.

    My Elling (see "CHILLER HELP, page 2 of Technical Discussion") has a plethora of wire colors: Brown, Blue, Red, White, Black, Green, and Yellow/Green stripe, and others. It's a virtual rainbow. LOL
    The tech working on the AC is telling me that the Brown & Blue are the neutral & common for the 115VAC, and that the Black & Red are the two legs of the 230-240VAC line. And that the Yellow/green stripe is also a neutral. Green is the bonding system (that much I figured out by looking at the bonding wires to equipment & home 110VAC grounding wires).

    The boat has a history of electrolysis; rudder post was compromised, thru-hulls discolored. When the technician opened up one of the air handler units, he discovered that the original installer in Netherlands had connected yellow/green stripe to a hot lead in the controller box.

    Further investigation of the wiring by the technician lead him back to the ER, where shore power enters the boat. He discovered that the vessel's bonding system (thick green wires) were connected to the Yellow/green stripe by a jumper, which is connected to bonding system.

    When connecting a volt meter from Leg1, or Leg2 to the yellow/green stripe wire, there is 123VAC potential between the two. When he makes the connection to the bonding buss, it the same value. If he meters from shore power Neutral to the yellow/green stripe wire, the voltage is .14. Also when he meters between the galvanic isolator and Leg 1, there is 123VAC again.

    The bonding system was supposedly "improved" by a contractor in Fort Lauderdale after I bought the boat. It was this contractor who connected the bonding green wires to the Yellow/Green stripe, via the jumper shown in picture.

    My electrolysis question: Has my AC technician discovered the primary source of my electrolysis?


    Neutral to Bonding system Jumper

    #1Grd to Neutral.jpeg

    L1 to Jumper

    #2Leg1 to Grd.jpeg

    L2 to jumper

    #3Leg2 to Grd.jpeg

    Neutral to jumper

    #5Neutral to Ground.jpeg

    L1 to Galvanic Isolator

    #6Leg1 to Galvanic Isolator.jpeg
  2. d_meister

    d_meister Senior Member

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    Conventional thought is that AC current does not cause galvanic corrosion, only DC. The purpose of the galvanic isolator is to prevent DC current from coming aboard from DC leakage on another boat.
    Rudder post corrosion may be poor bonding to the sacrificial anode bonding system or depleted oxygen corrosion. How was the damage discovered? Has the anode ever been completely wasted?
    Isolated through hulls wasting are most likely poor bonding. If they're all discoloring to a greater or lesser extent, assuming the color is brightening of the copper in the bronze, then the difference in wastage among them could be wetted surface or proximity to the stray current source. Although if they are all affected, it indicates the bonding system is providing little protection. If they're coloring from bronze to darker, almost black, with some green, it's from moisture. What is the design of the bonding system? Is it transom or hull zincs, or shaft brushes and shaft zincs? If brushes, they should be metered and good contact verified often. If transom or hull zincs, they should be wasting at a rate sufficient to prevent growth attaching, if you can see them. Shaft zincs should require regular replacement, too. Zincs that don't go away aren't working.
    None of the readings described or shown are unusual, or an "AHA!" moment, as regards corrosion, or even AC issues, but the AirCon hot connected to neutral and connecting to bonding could result in a swimmers electrocution if connecting to a solid ground when climbing out of the water. If the AirCon circuit was energized when hauled out, someone could have felt a tingle, or worse, when in contact with boat metals.
    When tracing and diagnosing AC faults, it is best to use a True RMS meter, like the big brother to the one shown, here.
  3. Seasmaster

    Seasmaster Senior Member

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  4. d_meister

    d_meister Senior Member

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    Are those photos from 3 years ago, or more recent?
  5. Seasmaster

    Seasmaster Senior Member

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    Photos from December2018. And the zincs were replaced in April of that year.
    Last edited: Sep 10, 2019 at 7:13 PM
  6. Seasmaster

    Seasmaster Senior Member

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    Here are pictures from April 2018

    upload_2019-9-10_19-16-3.jpeg upload_2019-9-10_19-16-3.jpeg upload_2019-9-10_19-16-3.jpeg
  7. v10builder1

    v10builder1 New Member

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    Seasmaster,

    In a simple 115VAC cord of European/Asian construction, brown is the hot (115VAC) and blue is the neutral. So I question the techs remark that brown and blue are neutral. Opinions vary, but on my 30 year old GRP (US operated, Taiwan built) boat with bronze thru-hulls, the bonding system is NOT connected to the AC electrical system (hot, neutral, or ground) anywhere and I do not have any thru-hull deterioration problems. My boat's bonding system is connected to the negative of the 12 VDC system.

    You probably have a 115/230 VAC hot neutral, or ground conductor connected to the bonding system somewhere.

    Assuming the dock pedestal is wired correctly and your dock cords are not modified, shut everything off and find the place where the shore power circuit from the dockside cord receptacle (on the boat) comes to your panel. Disconnect whatever you have to to isolate those 4 wires. They will be L1, L2, N, and G. Make note of the colors. You/your tech now know what voltages are seen incoming, for sure. There should be no connection between N and G on the boat while on dockside power - that connection is made at the dock/panel. The fractional AC voltage measured was probably correct. Do not start the generator. You now have to go through each and every piece of gear to insure that no electrical connections (L1, L2, or N) on the gear are mis-connected to G. The case of equipment is/may be connected to G. There should always be a high resistance (millions of ohms) between any circuit conductors (L1, L2, and N) and G when checking equipment on the boat (remember to unplug the dock cable while making these tests to eliminate the dock panel NG bond connection), and, IMHO, no connection (millions of ohms) between the bonding system and L1, L2, N, or G. You will have to check all cord/plug connected equipment on the boat, too.

    Have you had any problems with the dock pedestal GFCI tripping at your home slip or when travelling?
  8. Seasmaster

    Seasmaster Senior Member

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    What I'd written, "Brown & Blue are the neutral & common", was written poorly, and most likely incorrect (fading memory etc), and so it should probably have been written "Blue & Brown are the neutral & common, respectively". And "no" to GFCI tripping. However, the breaker on the isolation transformer usually takes 2-3 tries to stay "on". Sorry if I'm a little "thick" on this electrical stuff.
  9. wdrzal

    wdrzal Senior Member

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    European voltage standards are between 220 to 240 volts @ 50 Hertz. You need to check by country. All appliances from a toaster to a microwave are 220,230 or 240 volts. There is nothing lower.

    The regulating bodies in the USA believe those voltages are unsafe for common appliances that use a standard plug and receptacle. There are exceptions, like a 240 volt window AC unit ,electric stove or dryer can have a dedicated outlet that matches the plug designed for that amperage.

    PS: When working with either wires you don't know the color code or countries that don't follow any code, just use what's available. And you have many separate systems both AC & DC like on a boat, a Multimeter with "auto detect" just set to volts & it determines current type is really handy.
    Last edited: Sep 12, 2019 at 10:48 AM

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