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Grounding your home base fuel tank

skukum12

MEMBER
The Last Frontier
What's the usual method for grounding the tank? Copper rod with a tie in to the pump? Does the ground rod need to be six feet long?

I have a 300 gallon tank with a DC fillrite pump. Thanks for the input.
 
Why not tie it into your house ground? My pump is 120vac. How are you powering DC? Power supply? The power supply must use ground with the line voltage.
 
Ground rod tip below any expected frostline depth. The rod can be removed later with a railroad jack and chain.

Gary
 
Needs to be on it's own ground rod. While there are various 'rules' about ground rods, to be technically correct, someone needs to run a ground conductivity test at the tank site. This literally tests how conductive the dirt is, which translates to how deep the ground rod needs to be. Less conductive = longer rod. If you can't get the conductivity test, drive a rod as deep as possible, then bond it to the tank. This is a safety item for ANY tank, regardless of power source or even without electrical power. It protects against static, near misses from lightening, and damaged/failed electrical equipment.

Even with the ground rod properly connected, make sure the pail, barrel, vehicle, or aircraft is grounded to the tank BEFORE you reach for the filler nozzle.

Web
 
Why? My tank was part of the hangar design and doesn't have a separate ground. My pickup had a 100 gallon tank in the bed for 25 years with no ground. Shoreside delivers fuel into my tank without a ground.
 
Is the tank inside or outside? If inside, then a ground rod may not be feasible. If grounded to water pipe, etc, make sure it's on it's own. If outside, then it needs it's own ground rod. There are scenarios where a broken or bad shared connection could leave the tank isolated from ground which means any short circuit from the building's power circuit would apply power to the tank. It could shock you or create the spark that lights up the fuel.

As for the tank in the pickup, it needs to be treated like the fuel tank in the airplane, when being re filled. Connect the ground bonding wire from Shoresides truck, before grabbing the filler nozzle.

I guarantee that if your tank has been in your pickup for 25 years, it's grounded somehow to the pickup body. That's all you can do in a vehicle mount. But keep in mind that since it's not usually connected to a ground rod, it's susceptible to static build up. This makes the bonding connection between your truck and the aircraft or your truck and the fueler even more important.

Also, when fuel trucks are parked they are usually required to be connected to a ground rod.

Web
 
12vdc tanks are typically bonded to the tanks they fill. Shoreside, surprisingly, doesn't use a bonding wire. Their hose and nozzle is bonded. While that may not be perfect that's how 99% of us with home-based, truck-based, or trailer-based tanks fill our planes, too. As for my tank at the house? It's on it's own foundation in a lean-to enclosure outside the hangar. The pump is grounded via typical three conductor wire and the power switch is grounded independently. No bonding cable for the planes. As for the guys I know with stand-alone 12vdc pumps on tanks in their yards? None is grounded. I've never seen a 12vdc tank that was. I'm not sure what it would accomplish. If the 12vdc is provided by a power supply that's running on line voltage the power supply would be grounded. Beyond that on the DC output, no ground.
 
"I could probably drive my car with my feet, but that don't mean it's a good f*&!@ing idea!" Chris Rock

Web
 
Why not tie it into your house ground? My pump is 120vac. How are you powering DC? Power supply? The power supply must use ground with the line voltage.

Its a stand alone setup run off a 12v battery and over 100' from the house.
 
Web, will the nozzle/hose accomplish the bonding to the tank from the plane? I was planning on driving a second rod and tieing into a ground cable to the plane.

Wait, I read your answer closer. I should run a ground from the plane back to the tank itself, then begin fueling.
 
Assuming the pump is attached to the tank? Then the pump itself is bonded to the tank. Drive a ground rod and be done with it. The ground for stuff like pumps is a separate circuit from a bonded ground, like the tank to the ground rod or the fuel truck to the tank.

Web
 
Web, will the nozzle/hose accomplish the bonding to the tank from the plane? I was planning on driving a second rod and tieing into a ground cable to the plane.

With the ground bond being the nozzle itself, any spark will jump from the nozzle to the filler neck.

The industry standard is to have a tank permanently connected to a ground rod. This eliminates stray voltages and static electricity from the tank. Now, when you need to fuel the aircraft, connect a bonding wire from the tank to the aircraft. This wire drains off any static from the aircraft so that there are no sparks when you touch the fuel nozzle to the filler neck. When you are done re fueling, put the hose away THEN disconnect the ground bond wire from the airplane.

I've seen a couple of ways of running the ground bond wire. Usually just a wire that you drag out to the aircraft before fueling. Some are mounted on a spring loaded wheel that retracts the wire automatically. The second way is to tape the ground wire to the hose itself and leave a length dangling at the nozzle end. This is handy but you have to remember to connect the ground wire before the nozzle touches the aircraft.

If you use a bonding wire from the tank to the aircraft, and the tank has a ground rod, you won't need a ground rod specifically for the aircraft.

Web
 
I don't dispute Web's advice at all. However I don't understand why the grounding precaution is not taken/needed with automobiles. Anybody know?
 
I'm kind of over-cautious at the gas pump. I saw a fire two decades ago with a Honda Civic at a self-serve.

So now I touch a bare rivet or exposed metal at the pump and my vehicle at the same time. Then I keep my hand on the vehicle and hold the nozzle for a second. Then go ahead and fuel. I never get in or out while fueling, either.

My newer truck has a fill inlet with a flap in it. The nozzle touches the inlet before the flap opens. That might be a help too.
 
Fuel station fires are examples of failure to properly bond. Sparks happen from two objects having different static potential. That has nothing to do with grounding. The reason your fuel filler has the little flapper and many fuel nozzles have collars is to reduce the chance of a combustible mixture being present at the filler. Static can't start a fire if the fuel-air mixture won't support combustion. That's a key safety point when filling an airplane, too.
 
As stated previously; ground circuits for any powered equipment are different circuits than bonding ground circuits. Perform different functions.

Web
 
Yes. I'm an NFPA Member. That paper is more geared to commercial facilities than a home tank. In fact most of our home tanks aren't approved for gasoline so the standard isn't directly applicable. Part 4.2.5 has very specific instructions for bonding.
 
Yes. I'm an NFPA Member. That paper is more geared to commercial facilities than a home tank. In fact most of our home tanks aren't approved for gasoline so the standard isn't directly applicable. Part 4.2.5 has very specific instructions for bonding.

That is correct......in fact, virtually all pickup mounted GASOLINE tanks are not approved either. Look at the approvals on the commercial bed mounted tanks out there....approved only for diesel fuel.

The hoses used at gas stations contain a bonding wire built into the hose. As Stewart noted, the little flapper in your tank inlet is designed to prevent a flame from going down into the tank, and the nozzle bonds the system to the car (at least theoretically) before the nozzle actually comes in contact with the car fuel.

If you look at the regulations, a truly "legal" fuel system is probably beyond what most folks are going to build. So, do the best you can.....Ground the tank, as Gary noted above, then attach a bonding cable to the tank/pump that's long enough to reach the airplane with a clip on the end.

That's probably the best you can do. Now, as to tanks.....venting gasoline tanks is a HUGE issue, and most of the tanks folks use aren't adequately vented. But, how many blow up? Not many.....just don't be one of them.

MTV
 
Here are some screen shots from NFPA 407. Nothing complicated.

Web
 

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Thanks for the links. I guess the issue with automobiles is that likely nobody would actually use an independent bonding connection. So other means of mitigation, like the flapper, come into play.
 
Yes. I'm an NFPA Member. That paper is more geared to commercial facilities than a home tank. In fact most of our home tanks aren't approved for gasoline so the standard isn't directly applicable. Part 4.2.5 has very specific instructions for bonding.
I couldn't view it but the index contained a section on Self Service that I thought might be applicable.
 
Stewart you're right, not much help there and thanks for the look up Web..

If I was doing it and I've been thinking about a trailer I'm thinking I would do it like this:

Trailer tank with 12v power to the pump (including jumping it from your truck) - When stored the tank should be grounded (Jumper to a grounding lug), if outside this should be to a properly installed grounding rod, if inside to the building ground.

Ground Tank with 120v power to the pump from a nearby structure the tank should be bonded to the power source ground and that ground wire should not be of a reduced size, even if via a 3-wire extension cord, and don't forget to bond any structure/awning, carport etc. over the tank to the ground as well. A separate ground rod in this condition could create a differential between the two ground paths.

Ground Tank with 12v power to the pump (including jumping it from your truck) - The tank would be ground isolated and should be grounded to a properly installed grounding rod.
and as other have apply said, the tank and fueling vehicle should be bonded together when fueling.



On a side note my structure insurance prohibits fuel storage inside the building unless in the vehicle's fuel system. So if I do a trailer I'll have to keep it outside, likely under a red-neck car port.
 
I still don't get why you'd ground a DC system. The requirement to bond is exactly the same with or without. Grounding is an electric code thing. 120vac is grounded. Nothing I know that's 12 or 24vdc is.
 
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