Grounding a fuel tank to prevent static electricity caused fire

[bostonwhalermontauk1965]

Hi
In the boat restoration I am finishing, I have an old steel gas tank, that ,looking back, I never hooked a ground lead to and definitley should have. I once saw a bad fire get started due to a cold dry day and a plastic race car fuel cell that was ungrounded being filled by a plastic can with a vinyl hose on it. Static electricity sparked and ignited one hell of an inferno out of the high octane racing fuel. My question is - I would like to convert to a plastic tank - so is there a grounding tab on these tanks as well? I assume you should ground these correct? I see a spot on my old steel tank for a ground wire - and is it O.K. do you think just to run a ground wire off the negative buss bar I plan on mounting in the center console to the tank? Thank you in advance guys - Paul

 

[modernrocketry]

Re: Grounding a fuel tank to prevent static electricity caused fire

My experience is with much bigger gasoline boats.
I had a 36' SeaRay that used gasoline and the tanks and fill nozzle were grounded -- both where metal.
They were ground to a thru-hull in the bottom of the boat. Not the electrical system.

If you change to plastic -- I'd also ground it. Plastic can conduct static electricity on its surface. That's why gas stations always ask you to remove containers from the bed of a truck and place the on the ground to fill them.

Not sure if this helps.

 

[bostonwhalermontauk1965]

Re: Grounding a fuel tank to prevent static electricity caused fire

I agree - and yes i want to ground the plastic tank. My question is where should I ground it too and will the new tank have a grounding lead on it? I am assume that the through hull ground eventually tied into the negative side of the battery being that boats obviously dont have earth grounds. LOL - but to be safe I just want to play it as safe as possible and make sure all is cool with tank install. Thank you

 

[Chris1956]

Re: Grounding a fuel tank to prevent static electricity caused fire

A ground on all permanent fuel tanks is necessary for a fuel gauge sender to work.

 

[rodbolt]

Re: Grounding a fuel tank to prevent static electricity caused fire

there is a difference between grounding and bonding.
the fuel sender is an active circuit and needs a ground path for current flow for the circuit to work.
bonding is simply to hold a part at a known potential difference.
no potential difference means NO current flow or sparky sparky.
all metallic tanks and mettalic fuel fills must be bonded to the hulls negative battery terminal at some point.
wont hurt to bond the metal fuel sender on plastic tanks.

 

[DianneB]

Re: Grounding a fuel tank to prevent static electricity caused fire

I am not sure what you would bond on a plastic fuel tank aside from the sender (which is the only metal in contact with the fuel).

In the case of the race car with a plastic fuel cell being filled from a plastic hose, there really isn't anything to bond. One would assume there was metal somewhere since a spark jumping from plastic to plastic is unheard of (unless the plastic contained a material to make it conductive, which some does).

When fueling a boat or an aircraft, proper procedure it to attach the bonding cable BEFORE removing fuel caps or bringing the hose near the filler. This is to ensure equal potential before there is danger of ignition.

 

[bostonwhalermontauk1965]

Re: Grounding a fuel tank to prevent static electricity caused fire

Isnt static electricity from a plastic comb after using it on your hair enough to ignite something? I know when I get out of the car in the winter time after my sneakers were on the carpeted floor mats - I always discharge static electricity from myself first by touching the car body before touching the gas caps - I even see labels on the gas pumps warning of similar static electricity caused ignition. And by always placing plastic cans on the ground before filling. I assumed that was to eliminate the chance of static electricity and it just made me nervous about switching to a 12 gallon plastic fuel tank that will be being filled in a fiberglass boat, off the ground, on rubber tires and not being able to place on ground every time you fill due to weight and obvious awkwardness and being an all around pain in the neck. I dont want to get carried away with overkill - I just want to make certain it is completely safe. Paul

 

[DianneB]

Re: Grounding a fuel tank to prevent static electricity caused fire

Isnt static electricity from a plastic comb after using it on your hair enough to ignite something?

Not usually. It takes energy to cause ignition and that requires voltage AND current. The amount of current available from static electricity depends on the mass of the charged item and the mass of the item receiving the charge.

I know when I get out of the car in the winter time after my sneakers were on the carpeted floor mats - I always discharge static electricity from myself first by touching the car body before touching the gas caps - I even see labels on the gas pumps warning of similar static electricity caused ignition.

That is true. The metal car body and YOU are both conductors and both have mass so the charge picked up by your sneakers on the carpet or clothes on the upholstery is transferred through the conductors and makes a spark.

And by always placing plastic cans on the ground before filling. I assumed that was to eliminate the chance of static electricity

Not quite. The purpose of placing the fuel can on the ground is to prevent pooling of gasoline vapour in the vehicle - it is the vapours after all that ignite, not the gasoline itself.

I used to work in design in the petroleum equipment field and be responsible for ensuring our products complied with regulations so the theory behind the regulations was part of my job.

For myself, I always use my body to discharge to the car body and then to the gas pump before dispensing fuel. I also don't get back in the car or do anything else until I am done, the hose is hung up, and the gas cap is back on. (Getting in and out is believed to be the primary cause of static-induced fires at gas pumps.)

 

[sasto]

Re: Grounding a fuel tank to prevent static electricity caused fire

If your interested in bonding your plastic fuel tank....maybe hose clamp a bond wire to one of the fittings. Be safe.

 

[bostonwhalermontauk1965]

Re: Grounding a fuel tank to prevent static electricity caused fire

Thank You DianneB for your input. With your knowledge of fueling - it does make me feel better about this. Good idea to Sasto also to fasten a bonding strap to the tank somehow too - hose clamp or zip tie sounds like a good idea - Thank you again