Proper Fuel Tank Grounding

[JCDSAIL]

I am replacing both fuel tanks on my Albin 36 DC. The old tanks had no ground wire connection. The new tanks have a ground connection point. I believe I need to attach #4 stranded wire to these lugs?
Question is where do I connect the other end? Negative battery bus in
Panel area?
We think the lack of proper grounding caused a pinhole leak in these aluminum tanks..

Thanks,
JCDSAIL

 

[Marin]

If your tanks are anything like ours they should be connected to the boat's bonding system. So they will be electrically connected to the boat's anodes in the water and protected by them, just like a through hull/seacock and so on.

 

[El Sea]

From what we see, improper grounding is one of the major causes of aluminum, other than ventilation.

 

[RickB]

From what we see, improper grounding is one of the major causes of aluminum...

And all this time I thought bauxite was the major cause.

 

[sunchaser]

Further to Rick's observation, saprolitic ground is a good place to look for bauxite to avoid exploration failure

 

[FF]

Perhaps the most important ground wire is the one that runs from the metal deck fill fitting , past the rubber fuel hose , to the fuel tank it self.

This is where any static electric would be created , AND where the diesel or gas fumes are.

 

[BelindaPhillips]

This post really helpful for me to know how to place fuel tank properly. If the engine block is a good spot, is that not the same as the negative side of my battery if the battery is grounded to the block.

 

[RickB]

This post really helpful for me to know how to place fuel tank properly. If the engine block is a good spot, is that not the same as the negative side of my battery if the battery is grounded to the block.

FF supplied the correct answer. The grounding point is for attaching a ground wire to the fill connection to prevent an electrical arc when the fueling nozzle is inserted.

Connecting the tank to the boat's bonding system isn't going to do anything. Unless your tank normally sits in a pool of seawater the zincs on your hull are not going to do much for the tank. If your engine room is awash, put a zinc on the tank side.
Did your old tank failed from internal corrosion? If the corrosion that caused the pin hole leak was on the outside it was a very localized corrosion cell created by moisture and some other piece of metal in contact with the tank and moisture. That kind of corrosion is not prevented by bonding the tank to the boat's ground system, it is prevented by keeping the tank clean and dry and away from other metal parts that are not bonded to the tank itself.

 

[rwidman]

If the fuel tank has an electrical level sensor, the tank may need to be grounded for the fuel gauge to work. In this case, the tank would be grounded to the boat's negtive power buss (the battery negative).

 

[rwidman]

This post really helpful for me to know how to place fuel tank properly. If the engine block is a good spot, is that not the same as the negative side of my battery if the battery is grounded to the block.

I wouldn't run a wire from a tank to the engine block directly, but yes, the engine block is connected to the battery negative.

 

[RickB]

If the fuel tank has an electrical level sensor, the tank may need to be grounded for the fuel gauge to work. In this case, the tank would be grounded to the boat's negtive power buss (the battery negative).

The ground wire on that sender should be connected to one of the fasteners on its mounting flange, not the tank. Run a two conductor cable between the sender and the display.

Do not use the fuel tank as a conductor in any circuit.

 

[sunchaser]

Al tanks can be problematic from so many different issues. Problems can arise from resting on a SS washer, wrong supports, water in the bottom of the fuel tank (isn't there always) , stray currents due to improper wiring such as level gauges, wrong sound insulation material (don't use lead sheets) improper welding rod etc.

Just yesterday I replaced a Seaward Al hot water tank with a Torrid glass lined, after 9 years the Al tank bottom let go. I really don't care to agonize over why it failed, Al hot water heaters don't make sense for too many reasons.

If the install is done right Al fuel tanks are successful. But if done wrong, watch out.

 

[boatpoker]

From ABYC H-33 Diesel Fuel Systems

 

[boatpoker]

and from E-11, AC and DC Electrical Systems

 

[doltuku]

thanks for all the information guys