Can I use an earth block as a bus bar?

Discussion in 'OnBoard Electronics & Controls' started by mascip, Apr 30, 2015.

  1. mascip
    Joined: Apr 2015
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    mascip Junior Member

    Hi, I'm working on my boat's 12v electrics.

    I bought this Bus bar recently for £11.50, and then came accross this Earth block for £1.50, which in theory seems to do the exact same thing, but it's smaller so it would fit better in my small electrical board in the cookpit.

    Also, because I have 3 rooms on the boat (tiny bed room, cookpit, and small living room + kitchen), I need to buy 6 of these: a positive and a negative for each room. 6 times £11.50 is much more expensive than 6 times £1.50.

    My question is simple: can I use this Earth block instead of the Bus bar, or is there any danger in doing so? The bus bas says it can take 100 Amp, while the earth block does not specify how much it can take. I know I will never use more than 30 Amps: fuses will ensure that. Also, I guess I would have to screw the earth block onto a piece of plastic; to insulate it.

    Any thoughts?
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    If you use fine stranded wire on the second type, it is necessary to put a tube fitting at the end to get a good connection. It is basically the tube end from a crimp connector. If you can't find them, simply cut off the end of a connector. That will keep the fine strands from being split and ending up between the setscrew threads.
     
  3. mascip
    Joined: Apr 2015
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    mascip Junior Member

    Very good trick, thank you gonzo :) I was wondering about the robustness of such connections. Do you do the same with all connections to terminal connectors, or is it not necessary because they are smaller?

    If I understand well, without a tube fitting, the individual wire strands might break. If I put a tube fitting which is too long, then I get no electrical connections between the wire and the earth block. So, I want the tube fitting to reach halfway under the screw, so it keeps the connection solid but the strands are still touching the metal in the earth block. Is that right?
    Also, would you crimp it so it doesn't move around the wire?
    I guess I could figure this out myself by test-and-try, but if you have specific advice I might as well take it :)
     
  4. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

  5. mascip
    Joined: Apr 2015
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    mascip Junior Member

    Thank you! Uninsulated connectors, it's obvious now :)
     

  6. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    Either those crimp things or a short section of small copper tubing.
    The rule is they dont like screws bearing down on small copper strands of the wires which tends to break-cut them. I have a ground buss bar from an old distribution panel I am using. I soldered the wire ends and screwed them down, but I have been planning to put some sleeve ends on the wires.

    If there is room you could slip a flat metal thin bar into the hole so the screw bears on the bar and the bar bears on the wire will also work fine. Maybe cut a piece of tin can and bend it to 90* on each side of the hole.
     
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