Fuel Tank Ground Wire

[ChrisOB]

I replaced my fuel sender and it works well, however upon removing the aft water tank i found that i have a wire going from the aft tab of the fuel tank to 'nowhere'.  I connected a new wire to that tab from the sender upon install, but did not question the wire that went from that tab aft.  I pulled it out and its just bare.  I am using Noah's pic here to show it, where does that normally terminate?

[Craig Illman]

Guessing maybe to ground the fuel fill deck fitting? To reduce risk of a static discharge.

Craig

[Jon W]

On my boat that wire connects the tab on the fuel tank to the negative bus. There is also a second wire connecting the fuel fill to the negative bus as well. The fuel tank float switch also has a negative wire connecting to the negative bus.

[KWKloeber]

Chris

The tank has two potential "ground" (ie, bonding) wires to it.

It needs to be bonded to the negative side of the 12v system (via the harness negative/engine block/battery cable, etc.) for the fuel gauge to work, and it and the deck fuel fill could potentially be bonded together to prevent static electricity from building up while fuel flows through the fuel hose -- you keep the metal fuel nozzel constantly in contact with the metal fill port (although for diesel fuel it is unnecessary because diesel is not explosive.)  By convention, these should be green (designating bonding) wires.

kk

[ChrisOB]

ok thanks, i will have to see if my fuel fill has an attachment for it, otherwise i will probably eliminate it as i have used it for 4 years with no ill effects.

[ChrisOB]

i already have a wire to the DC ground from the tab so the tank itself is grounded, that wire was a floater. 

[KWKloeber]

There should be a round head #8 machine screw that threads into the body, to attach a wire w/ ring terminal.

ken

i already have a wire to the DC ground from the tab so the tank itself is grounded, that wire was a floater.

[ChrisOB]

assuming that means on the inside of the filler.  i will check that thank you.  my filler is a bit green with some corrosion.

[Noah]

That and these photo are OLD.  I have since "cleaned" up and properly connected/re-crimped the wires.  On the OEM (at least what I believe is/was the case) the black wire on the tank comes from the instrument panel then continues on to the ground, then tied into the ground at/on the Facet fuel pump. The green wire runs to my negative buss in the engine compartment. Perhaps overkill with two ground however, I ran another when I was troubleshooting my jumping/fluctuating fuel gauge, which infarct wasn't a ground issue after all and turned out to be a bad float sender.