I keep 3 to 5 drums of fuel in a storage container. This "sea can" is very well vented and stays close to outside air temp (does not get humid, etc).
I recently rec'd a friendly email reminding us racers of the importance of grounding fuel drums to eliminate static electricity which may cause a spark when opening or dispensing fuel.
I want to ground these drums, but don't exactly no how!
Can I get a grounding rod from, say, Home Depot and pound it in the ground, then ground the storage container, and put grounding straps to each drum?
Or am I missing something?
All positive and helpful advise VERY MUCH APPRECIATED!!
Always a good idea. The aircraft folks are big on this.
That's pretty much it. In the aircraft world they also use a bonding jumper connected to the aircraft to insure there is no electrical potential difference between the fueling equipment and the aircraft before they connect the hose and start transferring fuel.
"Pete C." (clip) In the aircraft world they also use a bonding jumper connected to the aircraft to insure there is no electrical potential difference between the fueling equipment and the aircraft before they connect the hose and start transferring fuel. (clip) ^^^^^^^^^^^^^^^^^^ Until you do the job "right," by installing solid ground connections to each drum, you should follow the procedure outlined by Pete, as used when fueling aircraft. Connect a jumper cable between the fuel drum and filling nozzle, or between the dispensing nozzle and the car's gas fill pipe, BEFORE you start the flow. If there is going to be a spark, it will happen then, so be sure to complete the connection in a location away from any fuel vapors. (Like, for instance, clip one of your jumpers to the supply tank, and the other to the car. Then connect the two cables together after stretching them out to their full length AWAY from both connections.)
You really ought to connect the aircraft and the drum regardless of how well the drum is grounded. The airplane is sitting on rubber tires. Maybe the rubber tires are conductive, but I would rather make sure both drum and aircraft are at the same potential.
At one time in my life I worked at a S Air Base in N.Thailand, and as "new Boy" in the Electric shop got the task of testing every grounding point in the parking ramp.
The normal grounding resistance of an aircraft ground is in the order of 10,000 Ohms as it is intended solely to discharge static electricity buildup.
If the same system is acceptable in a fuel storage yard then a simple copper ground rod driven in one corner and cables run to each drum with alligator clamps for attaching to the drums should suffice. Bruce in Bangkok (brucepaigeATgmailDOTcom)
Where do you drive ? IF it is dry, dry, dry - then no current would pass.
Dump some water on the rod in the ground - have it trickle down the rod.
You can have a screen (wire mesh) that you drive up upon and the car presses it into the earth - making contact - e.g. not driving a rod and then pulling it back out!
At a track or such - then there must be a good rod ground - maybe with a drip line - near the refueling point.
Don't worry about a ground rod. The "grounding" here is really bonding and is to ensure both your drum and anything connected to it is at the same potential (voltage). If they are at the same potential there will no spark when the hose is connected. From
"When fuel is dispensed, the nozzle should be inserted into the vehicle's fill pipe and contact between the nozzle and the fill pipe maintained to provide for an electric bond until the delivery has been completed. "
The hose of the petrol pump has wires embedded in the rubber that ensures the vehicle, nozzle and pump are all connected together. When a road tanker is refilled a bonding wire that is attached to the pipework is clamped to the vehicle before the hose is connected.
Whether or not they are actually connected to the physical earth is irrelevant, consider the situation when aircraft are doing air to air refuelling.
Ensure your drums and vehicle are electrically connected together before you fill. Hope this helps.
-- Regards Malcolm Remove sharp objects to get a valid e-mail address
That's how I have it - a "beam clamp" (available from Home Depot) clamped to the rim of the drum, 1/4-20x1/2" screw in the vacant hole of the beam clamp, 1/4" crimp lug, length of #14 wire down to an 8' ground rod and a ground rod clamp.
The beam clamp on the drum rim is the important part, so the screw tip bites through the paint on the drum down to the metal and makes a good ground connection. The alligator clips alone are not going to reliably bite through to metal every time or stay bit.
I don't want to trust safety solely to the conductivity of the paint on the drum - some might be low and others high, it's not something most people think about when selecting paint, they just grab a rattle-can of the color they want and blast away.
You could make temporary grounding connections at the drum using oversized alligator clips to the beam clamp screw, that will be more than solid enough.
And the petroleum product rated hoses used on portable drum pumps are SUPPOSED to be static conductive, but you could easily disrupt that using the wrong thread compound on the fittings. Better safe than running for your life...
Do you have pressure/vacuum relief valves on each of those drums? (I use a manual-vent relief valve in a 2" NPT Tee on the riser of the drum pump, to leave the other bung free for filling and gauge-sticking.)
Are the drums sitting in some form of secondary containment? (85-gallon HDPE Overpack/Salvage drums are cheap insurance against a drum rusting through. You may have fumes collect and a fire hazard, but the fuel won't just leak and seep into the ground un-noticed.)
I'm a painter at a shipyard where we use 55gal drums of toluene. The law requires us to ground the drum to earth and bond the drum to the container we are filling. We use the beam type clamps mentioned in a previous post. The tip of the screw is sharp and goes through the paint into the metal.
We are also required to ground the paint pumps to earth and bond them to any container we spray paint or toluene into.
It is very easy to to have a fire from static electricity.
trust me I've been fueling my aircraft with avgas out of drums for 10 years now.
grounding your drums to earth is a waste of time. they are sitting on the ground that is contact enough.
the problem is one of static electricity. static electricity migrates to the outside of the drum so it is easy to overcome it.
the problem arises if the point of contact between a drum and a vehicle with substantial static charge difference occurs through the fuel vapour as the hose contacts the refuelling inlet. you can get a spark occuring in an explosive vapour area.
the simple solution is to take a roll of automotive electrical wire and connect an alligator clip to either end. use a volt meter to ensure that you have electrical continuity between the two clips.
just prior to refuelling clip some part of the engine with one end of the lead described above and clip the other end of the lead to the drum. we usually connect an exhaust pipe one end and a bare area of a drum the other end.
that will bring both the drum and the vehicle to the same static potential and you can refuel in complete safety.
it really is as simple as that.
if you dont have that a piece of bare fencing wire laying across the two will suffice. all you need to do is equalise the static charges between the two. it doesnt matter if they are both at 1,000,000volts to ground as long as they both have the same charge.
Great replys all... thanks for taking the time to help.
I need to clarify something, and ask another question.
These drums are INSIDE the storage container, they are not touching the ground. The sea can has thick wood floors, and sheet aluminum skin. I take these drums, put a drain valve into the small threaded bung, then put them on a "barrel buddy", and the drum is 'levered' over on the barrel buddy to be on its side. I then fill up 5 gallon jerry cans, and then load them in the trailer. We take about 6 jerry cans per event. We do not use a rotary pump, and we do not transfer the fuel directly to the car from the drum.
If I am going to make sure the drum and whatever I am filling is at the same electrical potential... how do I do that with a plastic jerry can? (honest question).
Also, the email was specific in saying that what happens in some cases is a thunderstorm goes thru, and the drum becomes static charged, then when you open the drum it can discharge (boom). If this is possible (I have no reason to doubt it), simply grounding the drum to a grounding rod should keep everything safe, right? THANKS
Plastic jerry cans approved for fuel are electrically conductive. Treat it as though it were metal. Bond it to the vehicle or other container. Make sure any funnel is also approved for fuels.
Merely opening a charged drum will not make it go boom. A spark is needed to cause an explosion and that spark needs to occur where the mixture of gases is right for combustion. This could occur when the already open container, or it's charged fuel, is brought into contact with a container charged to a different voltage. That is avoided by bonding them together first. As I and several others have pointed out, a grounding rod is completely unnecessary.
-- Regards Malcolm Remove sharp objects to get a valid e-mail address
Normally both the aircraft and the fueling unit are grounded to "ground" receptacles embed ed in the concrete parking area. The "grounding" is a protection to static electricity only.
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