Boundaries of a complete electric overhaul

Discussion in 'OnBoard Electronics & Controls' started by papabravo, Apr 21, 2013.

  1. papabravo
    Joined: Sep 2012
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    papabravo Junior Member

    I now have a 35 foot, 40 year old project boat. As can be reasonably expected from a boat this age, there are gremlins in the electrical system. It's a 12V and 120V system... and the 120 is not factory.. but an add-on by a non-electrician, about 5 years ago.

    I plan a complete overhaul. Question I have is this: should I pull and replace all the wiring? Or should I leave the wiring in place (most of the time) and just install new equipment and clean the connections of the wiring in place?

    I think I want to re-use the wires that are there. But there is a certain future confidence if I re-do the wires as well. ..and maybe the Gremlin is a frayed wire that needs attention. But is cutting/pulling/re-strining wires more work than I guess?

    Regarding the 120: at least whoever did it used marine grade conduit. The non-professional hint comes out in this: EVERY outlet is a GFCI. A licensed electrician would have used one or two GFCI outlets, which would also served the other downstream outlets.
     
  2. PAR
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    PAR Yacht Designer/Builder

    You can often reuse old wire, though some tests should be preformed and the wire itself should be inspected for corrosion and compliance.

    If you have all GFI receptacles, then the "electrician" wasn't and frankly didn't have a clue, so this stuff should be suspect. This would include everything from cable clamps to wire type. I'll bet the GFI's are Lowe's/Depot, which aren't acceptable for marine use.

    More often then not, when I get a job like this, it's easier to just pull it all out and put in what you know to be correct. Good quality AWG, duplex, pre-tinned for the 12 VDC and the same in triplex for the 120 VAC system. Just figure out your needs, make a rough diagram and work out how may linear feet you need of each gauge, then buy it in roll bulk (it's cheaper this way). The same is true of receptacles, switches, breakers, light fixtures, etc.
     
  3. CDK
    Joined: Aug 2007
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    CDK retired engineer

    Whether to use GFI's for each outlet or just central ones is a matter of personal preference. The previous owner may have once had a bad experience or a salesman made him an offer he couldn't refuse.

    For a complete overhaul, start with drawing the exact circuit you think you need, with colors, wire sizes, functions etc. Once you are sure, make your shopping list.

    Then rip out all the old stuff: lots of wiring probably has lost its function during the past 40 years or has been modified several times and what still is in use is too old to be reliable.
     
  4. papabravo
    Joined: Sep 2012
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    papabravo Junior Member

    Thanks for your replies. I'll definitely go the re-wire route.

    Also as your post stirred a thought regarding a drawing: I am going to draw a schematic.

    I was going to rewire as I go--duplicating previous system in situ.

    Changed my mind, now I will draw a schematic:
    1. it will help me plan a bill of materials (shop for price/avoid work stalls due to no part)
    2. get a quote from an electrician
    3. use as documentation for future trouble shooting

    I was going to do it myself. But now am open minded to hiring an electrician. If an electrician can do pretty reasonably, I'm going in that direction. I know that will help re-sale.

    Can you suggest any internet tools available for a amateur to draw a schematic? I'm thinking of using Google's Power Point and making the file open to others as needed.
     
  5. daiquiri
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    daiquiri Engineering and Design

    I guess that by now nearly every bigger manufacturer of electric components offers freeware software tools for design of electric circuits (with their components, of course). They usually only require a registration to their site. Most of those I know and use are from italian manufacturers (Bticino, Gewiss etc.), but there's also the Swiss ABB and it's DOCwin software (in English).
    As I'm based in Europe, I can't help when it comes to US firms which might offer the same services.

    Cheers
     
  6. PAR
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    PAR Yacht Designer/Builder

    If you string GFI's along on the same circuit, they tend to trip each other or become overly sensitive. The way it's supposed to be done is a GFI at the feed of the circuit (first one in the series) and standard receps from there on down the line. Conversely, the preferred method is a GFI breaker in the panel and conventional receps throughout the run. This method costs more, but prevents issues.
     
  7. daiquiri
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    daiquiri Engineering and Design

    In a hope that we are talking about the same device (RCD, GFCI, GFI - all synonyms), I will agree that one RCD (I would have put it in a switchboard) is sufficient for all downstream electric loads. However, nobody prohibits putting several of them along the circuit, as long as their rated tripping currents (sensitivity) are different - decreasing towards the end of the circuit. This precaution, as well as the correct choice of the characteristic curve, ensures they won't trip randomly in case of a ground fault.

    At the end, it actually depends on what one wants to obtain, how much space he has in the switchboard and how much money he wants to spend. The advantage of having one RCD for all the downstream electric loads is the saving in cost and space. Having several of them allows to quickly and easily isolate only the faulty electric device, without interrupting the current supply to the rest of the electric system.

    Cheers
     
  8. PAR
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    PAR Yacht Designer/Builder

    I understand the way they work and the regulations, but folks that string along GFI's usually do so, because they haven't a clue about what they're doing, so they buy a box of GFI's, all rated the same and you inevitability get a sensitivity fight in wet locations. I've diagnosed this issue countless times and it's a very, very rare occasion to find descending sensitivity rates on down stream GFI's. The RCD in a breaker panel route is more costly, but offers the most room, as you've pointed out. The lead GFI in the string is the most economical method (only crowding one recep box) and faults along the string, are usually obvious.

    My point is anyone that's done this, typically doesn't have a clue about the requirements and the whole system should be suspect. I recently rewired a guy's center console. The previous owner had used THNN throughout the boat and though it was mostly working, I wouldn't let the customer out of the shop without replacing basically all of his electrical. The customer wasn't pleased, but once I showed him other stuff, he got on board. For example, the previous owner had a battery compartment, with a battery in a tray (no box), which was strapped down, but also in this sealed compartment was a water separator and fuel lines. I opened the compartment and removed the hot leg from the battery post, with the nav lights on (intentionally on my part). I asked if he saw that arc, which he did, then I suggested a leaking fuel line going into the separator could cause a problem. This got him on board with the redo of his electrical. I moved the separator to the outside of the compartment, where it can be easily changed and vent freely.

    Simply put, I see owner "inventiveness" all the time, but most of the time they're shooting themselves in the foot with "economic" efforts. This particular customer, realized he was just waiting for an explosive issue to rear up, so reluctantly got on board with the redo.
     
  9. alan white
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    alan white Senior Member

    Your seller may not have been a complete idiot. Nor would the many seperate GFIs be a problem UNLESS by testing the first box in the circuit (by pushing the test button), the rest of the downstream circuits also are disabled. The reason is that while GFIs can be wired in such a way that one GFI can serve a group of other locations, it can also be wired so that it only serves the box being tested.
    If the former owner was worried about failure of a single GFI and consequently the loss of every box it served, he might have just decided to spend on seperate GFIs for each outlet. Actually, I would consider that way of wiring to be more reliabe than using a single GFI for all the downstream boxes. Overkill, yes, but not a reason to replace everything at all. Only if each GFI in several boxes was depndant on the last boxes for power would that be a problem (extra sensitivity, etc.). If each is getting power directly from the panel, it means you don't lose power to all the other boxes when you blow the single GFI.
    You said the wiring is only five years old. My guess is that it may be a perfectly good job in terms of solid connections and guage of wire.
    so maybe you could have an electrician LOOK at ther current wiring and judge the actual situation.
    It may be that rewiring would accomplish nothing except to cost you lots of money.
     
  10. jonr
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    jonr Senior Member

    I agree with Alan. There are advantages to more localized GFCIs (think stumbling around in the dark trying to find the right outlet vs pressing the reset button right in front of you) and why replace in cases where you can inspect and test to verify that everything is correct. Maybe I'm just not a "buy a new boat every 5 years" kind of guy.
     
  11. papabravo
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    papabravo Junior Member

    Thanks. Good points. I will have an electrician look.
     
  12. tunnels

    tunnels Previous Member

    Nothing worse than wiring problems of any sort !!

    TECHNOLOGY AND EQUIPMENT AND MATERIALLS USED HAS CHANGED IN RECENT YEARS !! i say for the sake of peace of mind all new wiring !! Use heavyer reather than small termonals the same all new crimp and solder all , Shring wrap and seal and use special sprays to seal and make 100% water proof for ever !!Nothing worse than wiring problems !!
     
  13. missinginaction
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    missinginaction Senior Member

    I have to agree with Allen on this one, but (ironically) I have wired my boat as PAR suggests. Hey, I should be a politician!:rolleyes:

    http://www.amazon.com/Boatowners-Me...=boat owners mechanical and electrical manual

    I've said this before but I think it bears repeating. Buy this book, read it carefully, study it as you look at the old wiring that you already have. You will not only be able to teach yourself good wiring practices (on a boat or anywhere else for that matter) but you will understand your purpose designed electrical system and you will know where to look and what and how to test when a failure eventually occurs. You won't be helpless.

    It's not that hard. You just have to educate yourself and pay attention to details. Look, I proofread your post. You can actually spell. Big words like "licensed electrician" and "confidence". OK, there is one typo but I'm sure it was accidental. You can do this. Just THINK.

    Alan and PAR can back me up on this. I didn't know a thing about boat building and had rudimentary mechanical and electrical knowledge a few years ago when I started my project. Learning has been the largest part of the fun of restoring my boat.

    I've found that the most satisfying part of restoring my 40 year old boat was designing the electrical system from scratch. One last thing, you don't need a computer to create a schematic. You can easily do it on paper using some colored pencils. Have an eraser handy.
     
  14. troy2000
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    troy2000 Senior Member

    There's a Kindle edition of this available, for those who own a Kindle or have a free Kindle account on their laptop or desktop computer. And it's cheaper than the hard copy by about ten bucks.....

    Kindles aren't really good for schematics, or any other type of detailed illustration; they're simply too small. But being able to bring the pictures up in the Kindle account on my laptop makes technical manuals and references like this one worth buying in Kindle form anyway. The only drawback is that Kindles, except for the Kindle Fire, are in black and white.

    I'll definitely buy a Kindle copy of this book, long before I get to the wiring stage of my boat. If I decide it isn't working for me, I'll bite the bullet and buy the hard copy too.....
     

  15. papabravo
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    papabravo Junior Member

    Funny. I DID buy that book. Arrived last weekend. It is an incredible book in many respects. It has so much information in it.. it would be a two semester college course. Basic Boat Repair 101 then Basic Boat Repair 110 the next semester.

    The hardcover and binding is nice in an era of paperbacks. Only wish would be for the font to be a scoche larger, and color photos.
     
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