Announcement

Collapse
No announcement yet.

4788 Isolation Transformer behind icemaker

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

    4788 Isolation Transformer behind icemaker

    I’m starting the installation of two isolation transformers on my 4788.

    Several of the group have installed their’s behind the icemaker. That makes sense, lots of room, and an easy wire pull.

    When I investigated that area ist is large but I am very concerned.

    Looking at the floor of the cabinet, there is nothing beneath it. The floor is only held in by the little screws you see in the angle.
    Then reaching down I realized that the back 6” of the cabinet is unsupported. It’s hanging in over nothing.

    What bracing have you guys done to make this area stronger? How did you install yours? I am concerned that in rough weather I could have an issue.

    Thanks!

    Click image for larger version

Name:	827FCB5C-1F92-468B-96D1-1B1F1CE1D349.jpeg
Views:	188
Size:	215.7 KB
ID:	489572Click image for larger version

Name:	672EAD4A-1F97-405E-B8F9-A38B9B9DD41A.jpeg
Views:	154
Size:	202.1 KB
ID:	489574




    Attached Files

    KEVIN SANDERS
    4788 LISAS WAY - SEWARD ALASKA

    #2
    Kevin,
    This is what we did. The 5/8” mahogany plywood is coated with thin epoxy and secured top and bottom. The transformers are thru bolted.
    2000 4788 w Cummins 370's, underhulls, swim step hull extension
    12' Rendova center console with 40HP Yamaha
    MV Kia Orana
    Currently Alameda CA

    Comment


      #3
      Originally posted by Woodsea View Post
      Kevin,
      This is what we did. The 5/8” mahogany plywood is coated with thin epoxy and secured top and bottom. The transformers are thru bolted.
      I took out the icemaker, planning on doing just like in your photo. Then I saw how little material would be holding up that 150 pound weight. Started worrying.

      Thinking about the rough seas I get into occasionally and worrying about the corners of the cutout giving way.

      Perhaps I’m over worrying.

      KEVIN SANDERS
      4788 LISAS WAY - SEWARD ALASKA

      Comment


        #4
        Kevin - IMHO on a boat there is no such thing as over worrying about stuff that can go wrong - if not well thought out. Overthinking, yes. Over worrying, no. I’m going through my own angst fest on battery cable size for house battery interconnects.

        On the transformers - good location, just systematically think through sheer strength and reinforce as needed.
        Patti & Gordon Lewandowski
        Sammamish WA
        1998 4788 (April 2018)
        ”Knot Home”

        Comment


        • Kwood
          Kwood commented
          Editing a comment
          I think you're right to be concerned. 150lbs shock loaded on that piece might be a problem. I'd look for a way to gusset it back to something substantial so the cantilever cannot flex under that load.

        #5
        Originally posted by Knothome4788 View Post
        Kevin - IMHO on a boat there is no such thing as over worrying about stuff that can go wrong - if not we’ll thought out. Overthinking, yes. Over worrying, no. I’m going through my own angst fest on battery cable size for house battery interconnects.

        On the transformers - good location, just systematically think through sheer strength and reinforce as needed.
        Thanks!!!

        I really like the location that Woodsea and others have used successfully, btw...

        I would be a LOT more comfortable if that huge cutout was not there in the middle, but that cutout is necessary to access the throughhull fittings behind it, thats why it’s there.

        Part of me says to beef up thazt space, and another part of me says to use the area behind where the vaccume used to go. That is a pretty easy cable pull now that the icemaker is out.

        My thought would be to glue and screw a 3/4” plywood backer to the flat surface and then screw the transformers to that. Then I could get to the connections if need be to test, and the force would be down. All the screws would then do is hold the transformers from sliding around.

        Here are some photos of the area in question.

        Also as a FYI, the outlet is OEM for the vaccume. It is corroded because of the master bath faucet right above it, and it’s being replaced and relocated. Right now the breaker is tagged out of service.

        Click image for larger version

Name:	2EBDC3CE-2956-4A5E-B4AF-0BE74AF9FA85.jpeg
Views:	115
Size:	300.3 KB
ID:	489912
        Click image for larger version

Name:	A160DA69-CD70-4822-A733-4E9FA3222DE3.jpeg
Views:	116
Size:	248.6 KB
ID:	489913

        Click image for larger version

Name:	FD39FFB7-E7E4-4A1C-A088-1E0C552CF9E3.jpeg
Views:	134
Size:	199.8 KB
ID:	489911

        KEVIN SANDERS
        4788 LISAS WAY - SEWARD ALASKA

        Comment


        • Pacrimrat
          Pacrimrat commented
          Editing a comment
          Kevin,

          My thoughts on this location that It's very susceptible to water. Over the years I've had the tub facet leak onto the vacuum and the shower sump overflow flooding the area. I think behind the ice maker is the best spot.
          Chris JM2C

        #6
        Kevin,
        We installed our transformers this past spring. We had a couple of rough days off shore this past fall coming up the coast around Cape Mendocino. Worst being 10-14’ on short periods from three directions. Felt like we were in a Maytag for several hours. Happened to pull out ice maker when we got north on another matter and inspected. So far so good.

        Our transformers emit a slight hum. I can hear it in the salon and guest head when the boats quiet. I’m glad it’s not closer to the master stateroom.
        2000 4788 w Cummins 370's, underhulls, swim step hull extension
        12' Rendova center console with 40HP Yamaha
        MV Kia Orana
        Currently Alameda CA

        Comment


          #7
          Originally posted by Woodsea View Post
          Kevin,
          We installed our transformers this past spring. We had a couple of rough days off shore this past fall coming up the coast around Cape Mendocino. Worst being 10-14’ on short periods from three directions. Felt like we were in a Maytag for several hours. Happened to pull out ice maker when we got north on another matter and inspected. So far so good.

          Our transformers emit a slight hum. I can hear it in the salon and guest head when the boats quiet. I’m glad it’s not closer to the master stateroom.
          That is a Great report!!!

          Sometimes I’m a worry wart!

          KEVIN SANDERS
          4788 LISAS WAY - SEWARD ALASKA

          Comment


            #8
            At the risk of sounding stupid, what is the purpose of installing isolation transformers?
            Rob
            Bayliner 5788
            'Merlin V'
            Vancouver BC

            Comment


              #9
              I know one reason is to eliminate possible issues with the new electrical distribution systems at marinas - the ones designed to just about totally eliminate stray current in the water. Why an isolation transformer makes the new ELCI (?) posts a non-issue is beyond me. Other than that I'm like you on this topic Rob - more or less clueless.
              Patti & Gordon Lewandowski
              Sammamish WA
              1998 4788 (April 2018)
              ”Knot Home”

              Comment


                #10
                Originally posted by MerlinV View Post
                At the risk of sounding stupid, what is the purpose of installing isolation transformers?
                The main reason is to eliminate low voltage DC currents from traveling through the ground wire of the shore power cable and corroding metals in contact with water. Here's a good article: https://shop.pkys.com/Isolation-Tran...able_b_37.html
                1999 3788, Cummins 270 "Freedom"
                2013 Boston Whaler 130 SS
                Anacortes, WA

                Comment


                  #11
                  Technical details aside, here is a very high-level summary to explain things. Electricity requires a closed loop to be formed.Two boats sitting in the same body of water side by side form a loop between them by way of boat-1, through the water, boat-2, the ground (green wire) of the shore cable to the dock panel, ground-wire from the shore panel through the shore cable to boat-1. Low amps, as it may be, this current causes corrosion in metal parts in the water. Isolation transformer cuts the loop off since the 1-to-1 transformer in the isolation transformer inserts a magnetic path (non-current conducting) that prevents corrosion. Galvanic isolator is another way to cut the loop off. Galvanic isolator creates a high-enough resistance that blocks low levels of current (so corrosion is isolated) but permits high levels of current to pass (so short-circuit protection is maintained). Since the loop passes through the ground wire of the shore cable, your boat is safe from this type of corrosion (there are also other types of corrosion) if you are not plugged into the shore panel with a 3-pronged (grounded) connector/cable.

                  Enjoy!
                  Retired, computer expert / executive
                  Bayliner 285 Cruiser / Mercruiser QSD 4.2L 320 HP Diesel
                  Live in the Bay Area, CA, USA, boat in Turkey
                  D-Marin @ Turgutreis in Bodrum/Turkey
                  bdervisoglu8@gmail.com
                  bulent@pacbell.net

                  Comment


                    #12
                    The new wiring standards of dock pedestals has caused some issues with connectivity to older boats. We wanted to eliminate the hassle and this is a sure way to do so.
                    2000 4788 w Cummins 370's, underhulls, swim step hull extension
                    12' Rendova center console with 40HP Yamaha
                    MV Kia Orana
                    Currently Alameda CA

                    Comment


                      #13
                      Which leads me to wonder - why don’t 4788s have the grounding thingy rubbing against the propeller shaft like so many other boats? At least ours doesn’t. And our 3988 did. I wonder because our three shaft zincs were really corroded after only 9 months in our marina. Sorry if I’m hijacking the thread.
                      Patti & Gordon Lewandowski
                      Sammamish WA
                      1998 4788 (April 2018)
                      ”Knot Home”

                      Comment


                        #14
                        Originally posted by Woodsea View Post
                        The new wiring standards of dock pedestals has caused some issues with connectivity to older boats. We wanted to eliminate the hassle and this is a sure way to do so.
                        That is one of the reasons I am adding them.


                        As I start to activly cruise I want to isolate my boats electrical system from the shore power system (and other boats) while still getting the benefits that shore power brings.

                        KEVIN SANDERS
                        4788 LISAS WAY - SEWARD ALASKA

                        Comment


                          #15
                          Posted on this once before. I placed mine in the aft cockpit lazarrette next to the battery charger. I wanted to create a new place to plug in too, since my boat is stern-in most of the time and the electrical pedestal is closest here. also, my boat lists slightly to the port and I wanted to counteract the weight distribution. Short runs for wire are also important. I then ran the wiring to ty in with AC up the starboard side directly to AC panel and added a breaker for this outlet. Then just tied into the appropriate electrical switch. The Charles G2 is only 30A but with the diesel furnace I do not usually draw more. If I do, I simply trip the breaker. Note: Charles calls out for a specific type of breaker, can't remember if it's thermal or magnetic. This setup also allows me to use the inlet on the side of the boat, and I simply flip the breaker to the rear inlet off. The area if the boat where G2 is mounted is simply retained by a 'shallow box' that keeps it put. The same area had originally held a start battery, which I had moved. And I still have access to crawl around the starboard side of the starboard engine. Not sure though how things are on the 47. Try placement first to see how it affects your boat floating in the water.
                          Ken

                          Comment

                          Working...
                          X