Grounding a Plastic Tank

[wilram]

How do I ground a plastic tank that has a fill tube without any metal for grounding purposes?

 

[LX Kid]

Re: Grounding a Plastic Tank

Can you post pics of your particular tank and fuel guage connections?

 

[tashasdaddy]

Re: Grounding a Plastic Tank

you can't plastic does not conduct electricity.

 

[TheWoodCrafter]

Re: Grounding a Plastic Tank

There would be no ground for that tank then.

 

[Dunaruna]

Re: Grounding a Plastic Tank

Is there a fuel gauge sender unit in the tank?

 

[redfury]

Re: Grounding a Plastic Tank

What would be the purpose of having to ground a plastic fuel system in the first place?

 

[fishrdan]

Re: Grounding a Plastic Tank

Is the tank removable? If so, then you are supposed to remove the tank and place it on the ground before filling. Plastic can build up a static charge and if discharged to the gas pump's hose while filling the tank,,, then BOOM I don't think I have ever heard of anyone blowing themselves up by not placing the tank on the ground, but I always do it, better safe than sorry...

The plastic 30 gallon fuel tank in my Crestliner has 2 grounds, 1 going to the metal filler neck and the other going to the engine block, don't remember where it's grounded on the tank, but I suspect it's on the fuel sender.

What type of tank were you working with?

 

[drewpster]

Re: Grounding a Plastic Tank

I cannot get the Coast Guard link to work. Can you give me the summery of what they say about this?

 

[Pascal]

Re: Grounding a Plastic Tank

My thinking is that his concern is with static electricity or ESD.

Plastic is a good insulator and also a good static generator. Grounding the plastic tank is the only way to dissipate the possible electric charge safely.

Fuel flow into a plastic portable fuel container has been the cause of static initiated fires at the pumps under certain circumstances.

http://www.doityourself.com/stry/fuelpump

http://www.pei.org/Uploads/static.avi

The avi is very interestin' though not related to boats or portable containers.


I would also be interested in what that USCG link said about NOT grounding.

 

[Pascal]

Re: Grounding a Plastic Tank

Found it.

The listing is in the archived alerts on the website.

The first line says "The metallic retaining chanin and cap of plastic body fuel fills should not be connected to the boats' bonding system."

There is a more link but it gives the same return as the link in bubba's post.

I think the key to this is "the boats bonding system". Sounds like it might be refering to the hull???

Does anyone have a clarifying thought on this terminology???

 

[reelfishin]

Re: Grounding a Plastic Tank

I'm not sure on what the CG says on grounding the tank itself, but my thought would be that even if the tank was grounded to the hull, the whole boat will still carry that static charge. I would think that the only way to dissipate that safely would be to ground the boat to the dock before putting the nozzle to the tank filler.
On some older marine gas pumps and many portable fuel filling stations there is a wire with an alligator clip in which to do so with. I have an older plastic fuel caddy that holds 30 gallons, its a plastic tank on a steel frame with rubber wheels. There's a ground wire on the top connected to both the metal frame and the ring around the fill nozzle. There's also a warning stating to be sure to ground the wire when filling this tank and when discharging fuel to the boat. The instructions say to connect the wire to the nearest metallic surface on the boat prior to opening the valve or placing the pump nozzle in the boat's fill neck.

I do know that if using a plastic tank in a car, the top ring or sender must be grounded to prevent explosion from static electricity. I've seen a few race cars burst into flames this way that were lacking proper grounds. Most filling stations at the track will refuse to fill a car with no ground, others keep a jumper wire to ensure a good ground before pumping fuel.

The problem occurs when the nozzle is not in contact with the filler neck, this allows the built up static charge to jump to the grounded nozzle which happens to be pumping the fuel. Since boat tank filler tubes are usually pretty small, it's rare that the nozzle won't be in contact with the fill neck.
By making sure that the nozzle is in contact with the boat's tank filler neck, it most likely will dissipate any static charge created by the fuel once the pump is turned on. I think on most boats it would be pretty hard to not make contact while pumping fuel into an onboard tank. I would never pump fuel into a portable tank while it was in the boat. Always fill them off the boat and I would say it would also be a good idea to make sure the nozzle is touching the tank during filling or to jumper the tank to the fuel fill manifold on the pump.

 

[j_martin]

Re: Grounding a Plastic Tank

Found it.

The listing is in the archived alerts on the website.

The first line says "The metallic retaining chanin and cap of plastic body fuel fills should not be connected to the boats' bonding system."

There is a more link but it gives the same return as the link in bubba's post.

I think the key to this is "the boats bonding system". Sounds like it might be refering to the hull???

Does anyone have a clarifying thought on this terminology???

The terminology, "bonding system" is an electrical term referring to the common ground of a device, dwelling, machine, etc. In a house it is the neutral return, safety ground, and an actual earth ground which all come together in the breaker panel. In a boat it would be the frame of the motor, and all paths to it, ie the negative cable to the battery, the ground wires in the electrical, etc.

At the bottom of this post I will tack on the full text of the coast guard warning. It seems to me that they do not recommend bonding the metal filling port on a plastic tank, but the last sentence seems to require it.

Mine's bonded, as are most boats. To prevent a spark from being generated, I hold the fuel nozzle in one bare hand, away from the boat. I lay my other bare hand on the engine frame. I then stick the nozzle in the fuel filler.
Just be sure it's the fuel filler, and not a rod holder.

hope it helps
John

<<tack>>
Plastic Fuel Fill Grounding

Recent events have caused the boating industry to examine the policy regarding the bonding of plastic body fuel fills with metallic caps and retaining chains. Existing USCG & ABYC policy states that the bonding of these components is voluntary. A study by IMANNA Laboratories has shown that connecting the metallic retaining chain and cap of a plastic body fuel fill assembly to a boat's bonding system may result in electrostatic discharge from a land-based fuel pump nozzle to the metallic components of the assembly when the boat is not in the water. This condition does not exist when the boat is in the water due to the equalizations of the ground potentials between the fuel pump nozzle and the boats bonding system.

It is recommended by ABYC and the USCG that new and existing installations of this type of fuel fill assembly do not include any attachment to the boat's bonding system. Existing connections should be removed from the point of connection to the boat's bonding system to the fuel fill assembly. Removal of the metallic components of the assembly is not necessary; however, the U.S. Coast Guard and ABYC still require that metallic body fuel fills be bonded.

For further information contact: John Adey, ABYC (410) 956-1050 ex, 29 jadey@abycinc.org or Richard Blackman (202) 267-6810 rblackman@comdt.uscg.mil.
[Posted: 7 February 2005. Source: Barbara Rhoades, BC-ASP]

 

[Mark42]

Re: Grounding a Plastic Tank

A few years ago I put a plastic tank in my MFG. The Coat Guard regs said that if the fill deck plate is metal, it needs to be bonded (grounded) if the fill tube is metal, it needs to be bonded, if the tank is metal, it needs to be bonded. Basically, any piece of the fuel tank and fill that is metal needs to be bonded. The plastic components do not need bonding.