1982 Fuel tank ground wire |
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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Posted: August-13-2019 at 10:42am |
DC ground originates at a main buss or battery negative and is intended to handle actual current. Sender ground originates at the instrument cluster or instrument or module and may be designed or intended to only carry reference current. Actual application may be of no difference or it may be of huge difference. Depends on how the boat was rigged. Is it electronic? Do you want your ECM reference ground handling what could be large voltage irregularities? Remember that the main DC ground will be effected by everything from voltage potential discharges to jumper cables on backwards etc etc. A nice little jolt through the N2K backbone or CAN bus may wreck your day. The standard is obtuse by design to cover that possibility as well as others.
Like I told MW. This is an old analog boat, just see if the tank and fill are grounded and go skiing. Just trying to help and never intended to put on a lecture. |
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Jesus was a bare-footer.............
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21184 |
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What differentiates “DC ground” and “sender ground” in your mind?
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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The regs change constantly so don't beat yourself up over it. If your tank and deck fill read good continuity to DC ground your OK. Go skiing. What I spelled out is the best case, perfect example. All I do at work is put a meter on the tank and fill. I will call bull*************** on using sender screws for ground though as many have isolation washers.
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Jesus was a bare-footer.............
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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Probably green and 12 awg. |
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Jesus was a bare-footer.............
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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Now I go over this I remember after the last burn ward trip I added a second ground jumper from the deck fill to the breast cleat on my fathers center console. He would rest the bottom the gas can against that cleat when filling anyway so it was an automatic safety. Sadly, both my dad and that boat are long gone.
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Jesus was a bare-footer.............
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 915 |
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So now I'm thinking...and trying not to overthink.
On this boat there was no ground wire directly to the tank "tab", nor a 'witness mark' indicating there ever was one. I assume this was in compliance with regs of the day ('82). |
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1964 Dunphy X-55 "One 'N Dun"
'I measured twice, cut three times, and it's still too short!" |
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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They serve different purposes. The tank ground is there to equalize electrical potential of all metals in contact with fuel storage. I suppose they consider remote filter placements as low risk but I have noticed that European builds will ground remote filters as well. The USCG calls for I think 10 OHMs minimum but ABYC wants <1OHM.. Forgive me if I'm a little off on the number, Its been a few years but I'm pretty sure I'm right.. The standard is clear that the tank should not be used to chassis ground a sender or visa versa.
It is good practice to touch the fuel fill nozzle or gas can to the fill cap before removing the cap. Any differential will be equalized at that point, not when you tip the can into an empty, vapour filled tank. I have taken statements in the burn ward twice. Once from a plastic can and the other from a gas station / trailered boat configuration. Ever fill an airplane with gas? Better ground it. Same principle. I suppose the signal ground wire may not meet the resistance qualifier for the standard. I have never tested it actually. just a theory. |
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Jesus was a bare-footer.............
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Why not? |
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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DC ground to tank tab or anywhere with good connection to the tank body. Ground jumper to metallic tank fill. Sender ground and sender signal wires to tank sender. Tank ground should not be used as a signal ground.
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Jesus was a bare-footer.............
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 915 |
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Got it...thanks for quick reply. Onward....
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1964 Dunphy X-55 "One 'N Dun"
'I measured twice, cut three times, and it's still too short!" |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21184 |
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Have seen both, either is fine.
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 915 |
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Re-installing fuel tank. Have dual ground wire, one wire goes to sender, the other the fill plate.
But there is a tab/hole welded to tank. Don't have any more loose wires, but thought a ground went here, or does tank ground through the sender screws? Thx |
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1964 Dunphy X-55 "One 'N Dun"
'I measured twice, cut three times, and it's still too short!" |
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