Grounding

Discussion in 'Electrical Systems' started by chuckms, Mar 27, 2011.

  1. michael pierzga
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    michael pierzga Senior Member

    It doesnt matter what the boat is made of. And you re playing with fire when not using the earth conductor.
     
  2. Frosty

    Frosty Previous Member

    If it were made of steel or alluminium!!

    And what would you be earthing with 2 wire appliances with 2 pin plugs
     
  3. michael pierzga
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    michael pierzga Senior Member

    Ungrounded appliances must be used on a circuit with a GFI.
     
  4. Frosty

    Frosty Previous Member

    How do you get a shock with a plastic electric drill? or a plastic toaster or a plastic everything------
     
  5. michael pierzga
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    michael pierzga Senior Member

    Take a shower with your toaster ? Drop a hand drill into your Mojito ? Chomp into your electric toothbrush ? Many fun and exciting ways
     
  6. CDK
    Joined: Aug 2007
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    CDK retired engineer

    There are a lot of these stories going around, but mostly not true. The aluminum ladder part makes me question this story also.
    I've spent my whole life working with electricity and received more shocks than the average technician, even lost consciousness more than once. But I still have all my limbs.

    With a proper GFI and good wiring such things are simply impossible.
     
  7. Frosty

    Frosty Previous Member

    Im not wanting to hijack this thread and im sure we will get on track soon but the above post is ridiculous. If you don't know say so.

    At first you said I was playing with fire.

    Mechanically explain how I can get a shock off an electric PVC drill by holding it. Even if I wired the live to the drill body. Wires are insulated with PVC and I can pick them up live.

    If you don't know say so.
     
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  8. michael pierzga
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    michael pierzga Senior Member

    Gee frosty..just touch the metal drill chuck when the drill developes an internal fault or binds up when drilling and chafes the cable. If the ac feed circuit is not fitted with a GFI you will be break dancing.

    And never assume the GFI will work. Earth is the first line of defense and always works. In marinas many times the GFI is disconected. Boats with poor ac installations frequently trip the GFI and the dockmaster is tired of travelling to reset the breaker..

    Follow the rules...use the earth connection... or use an isolation transformer or if its a small craft use a galvanic isolator.

    This topic was about electrolsis on boats. Both the galvanic isolator and the isolation transformer will keep stray current from seeping into a boat via the earth wire.
     
  9. DianneB
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    DianneB Junior Member

    Frosty: Two-pronged electrical appliances are referred to as "double insulated", in other words, there are two separate and distinct barriers between the electricity and your hand WHEN USED IN THE DESIGNATED ENVIRONMENT! Every single one of those appliances will have a note (in the user's manual) to use them only in dry locations or connected to a GFI receptacle.

    When applying for CSA or UL approval, the testing agency is allowed to introduce ONE fault and the appliance must remain safe. One of the cheapest methods to remain safe is to build in an extra layer of insulation so that only one can be faulted. This does NOT remain safe when used in a location for which the product was NOT intended - like using your electric drill outside in the rain or submerged in your pool!!!! You are NOT protected as the water will fault BOTH layers of insulation and you WILL get zapped!
     
  10. Frosty

    Frosty Previous Member

    You know I never thought of using a drill in the rain or taking a shower with a toaster,--I suppose I must be a bit strange.

    I guess a GFI would save me from utter, unbelievable stupidity.
     
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  11. michael pierzga
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    michael pierzga Senior Member

    Yes indeed ...GFI's are cheap, easy to install and should be fitted to every wall outlet circuit on a boat.
     
  12. chuckms
    Joined: Mar 2011
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    chuckms Junior Member

    Earth Ground

    Thank You all for the great advice. I disconnected the Shore Power from my boat (Fiberglass Hull for those who asked) and disconnected both the Positive and Grounds from all my battery’s and had 6volts from the water in the bilge and my engine (nothing running) I then checked at my dock and had 12 volts. I shut down the power to my house and still had 12 volts. I started checking the neighbors to the west and found all of them to have a problem. I checked my next door neighbor to the west and found a receptacle on her dock with DO NOT USE written on it. I dropped the positive of my volt meter in the water and the negative in the ground on the receptacle and had 117 volts and had the same reading on both legs of the receptacle. My neighbor came home a little later and I told her we had a problem, she quickly replied O don’t use the bottom receptacle I need to get it fixed. I told that would be a god idea before her grandchildren went swimming. I showed her the voltage and asked if she could turn off the breaker on her panel to see if it went away. When she tuned off the Boat house breaker the Voltage read 0. It was strange that the voltage energized the water as her boathouse has no earth ground and this receptacle is run in plastic conduit under her dock to her house on the land side of the sea wall. My neighbor had work on her dock several months ago and I am sure they must have cut into the conduit when installing the steel rods used to tie back the sea wall sending the stray current to the water. The moral of the story is ANYTIME THIR IS WORK TO DONE WITHEN 500’ SITE OF YOUR BOAT YOU NEED TO CHECK FOR CURRENT IN THE WATER. This cost me several thousand dollars and I almost lost my boat. The first this to fail was the through hull then the Heat exchangers then the manifolds. The softest metal first. I am very grateful for the advice I got on this site as I was looking in the wrong direction and would have had more damage or injury if I did not find the problem. THANK YOU:
     
  13. chuckms
    Joined: Mar 2011
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    chuckms Junior Member

    I should spell check next time before posting
     
  14. sdowney717
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    sdowney717 Senior Member

    once I was drilling a hole in the wall under the sink with my double insulated drill plugged into a GFCI outlet.
    And some water from the drain pipe ran onto the drill and I got shocked. Enough that I had a hard time letting go of the trigger.
    So later I tested the GFCI with the push button and it passed but is that gfci really working.
     

  15. sdowney717
    Joined: Nov 2010
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    Location: Newport News VA

    sdowney717 Senior Member

    chuckms, does the boat have a galvanic isolator in the ground circuit?
    This disconnects the boat ground from stray currents coming from the water or shore below a certain voltage and also DC leakage, but conducts when a genuine short to ground happens.

    http://www.boatus.com/seaworthy/galvanic/default.asp

    [​IMG]

    looks like they are only for DC leakage
    http://www.yachtingmonthly.com/plus/409969/non-isolating-isolator
    Would an ELCI gfci 30ma breaker have detected and tripped ?
     
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