Kevin,

I am in the process of restoring a pontoon boat and doing some research on the fuel system.

If using a plastic fuel tank with rubber hoses that go from the tank to the metal deck fill on the side of the railings, should you ground the metal inlet to eliminate any static charge?

The U.S Coast Guard’s Boating Safety website says that any portion of the fuel system that is metallic has to be grounded. This confuses me because if you ground the inlet, it will essentially ground the entire marine electrical system, which could potentially cause corrosion issues.

Any advice you can give me would be great.

Thank you,

Bill

Hi Bill,

It is important to ground all of your boat’s metal fuel fill components together to prevent accidental, static discharge.

When fuel flows down a hose, the swirling action creates a static buildup. If the fill is not grounded to the tank, there is a change of a static discharge when the pump is removed from the fill which can cause an explosion. If the fuel fill is made of plastic, this static ground wire is not required.

Galvanic corrosion (the corrosion that occurs when dis-similar metals are electrically connected) will not be a concern. To cause galvanic corrosion, the two pieces of metal need to be electrically connected and submerged in the same body of electrolyte (water). If your boat’s fuel fill and tank are continuously under water, you have more serious concerns than galvanic corrosion.

Please let me know if you have any other questions,

Kevin

Kevin,

Thank you for quick response.

The way the boat was originally wired, there was a tank ground wire from the filler to the negative terminal of the battery.

The tank is plastic so I do not think bonding them together would discharge the static energy. The only metallic portion of the fuel system is the filler.

Is this the correct way to go about this?

Again, thank you for your help.

Bill

Bill,

Beyond connecting all metal components in fuel system that can come it contact with fuel, the system must also be connected to the boat ground.

The full intent of this practice is to give a low resistance path back to ground – metal fill – wire to tank – tank – to ground on boat – ground connected to metal underwater gear – boat in water – that will help prevent static discharge buildup.

• If your boat fuel tank has a fuel gauge sending unit, connect the static ground to the sender and the sender ground to the battery negative/ground bus.
• If your boat does not have a sender, connect the static ground wire directly to the battery negative/ground bus.

Hope this helps,

Kevin

Kevin,

This clears it all up.

Thank you very much for your help.

Bill

Hi Kevin,

Could you please answer a question on adding a negative ground bus to my boat wiring setup?

I’ve found metal parts of my boat which are not grounded, like the gas tank, gas deck fill…is grounding these as simple as installing a bus wired to the negative post of the battery and then running a wire from each of these metal parts to the bus?

Thank you, Mike

Hi Mike,

There should be a static ground wire that runs between your deck fill and your gas tank. The gas tank should be grounded to the boat grounding system.

The metal case of AC components should already be connected to the boat’s AC grounding system.

Metal, underwater gear should be connected to a common grounding bus. It should have a single connection point to the battery negative.

Here is a link to ABYC E-11. This goes into detail on how to correctly ground a marine electrical system.

Good luck,

Kevin