al, by the sounds of things, you should stick to concrete. Your trying to BS your way around everything is getting old. Feel free to paste this in your response.
You talk of an "earthed wire", just where do you think 99.999999999999999% of them are connected?
Your attempted analogy's are FOS. Really desperate as a matter of fact. "Static, Water, Fuel",,,,,,,really,ROFLMAO I'll remember that next time in the pool, or stick my finger in a gas tank.
Here al, it don't get much simpler than this....
Grounding Aircraft
During refueling fuel is transferred from the fuel truck or underground tanks (sometimes above ground) and this process can cause a static charge to build up between the aircraft and fueling device. This is the same principle as walking on a carpet in wintertime and getting a shock from the doorknob when opening a door.
Testing has shown that when people 'feel' this shock the voltage is at least 3500 V. Amperage is very low so no real power is transferred and no harm done, but it can be uncomfortable though. Delicate electronics or aircraft avionics can be 'killed' by voltages much lower than this.
Static Electricity
According to Wikipedia the definition of static electricity is as follows:
"Electrostatics (also known as Static Electricity) is the branch of physics that deals with the forces exerted by a static (i.e. unchanging) electric field upon charged objects. Electrostatics involves the buildup of charge in objects due to contact between (generally) nonconductive surfaces. These charges are generally built up through the flow of electrons from one object to another. These charges then remain in the object until a force is exerted that causes the charges to balance e.g. the familiar phenomenon of a static 'shock' is caused by the neutralization of charge built up in the body from contact with nonconductive surfaces."
Static buildup
It is important to understand how static electricity is build up. As in aircraft operations like refueling this can create dangerous situations. An aircraft flying through the air can also build up static charges. To discharge these build up electrons special devices are attached to ailerons and tail feathers to return these electrons to the surrounding air and they are called 'static wicks'.
Without these so called 'static wicks' an aircraft would experience radio and navigation difficulties due to static discharges on the outside of the aircraft.
Fuel (dis)charging
When an aircraft is refueled fuel is pumped from one container to another and throughout this process the fuel charge level is determined by several factors: pump rate, temperature and humidity. This charge is build up between the two containers. When the charge is high enough to jump between the containers, a spark will occur. If there is a combustible mixture near the spark (above/near the fuel cap) a fire or explosion could happen. And this is the reason why a ground wire is connected from the fuel station to the aircraft whenever fuel is being transferred.
Defueling
There are two area's where a pilot should exercise caution when transferring fuel. The first is when draining an aircraft tank. During this draining fuel is transferred and a charge can build up. Connecting a ground wire from the aircraft to the fuel container makes sure a voltage differential cannot develop and eliminate the change of a spark from aircraft to container.
Just remember, when you are draining fuel, there can be enough air in circulation so that the fuel/air ratio is in the combustible range. And one spark can do the trick..
Fueling
The second problem area is the filling process. Many fuel stations use a ground wire when refilling an aircraft and this is good. But when the aircraft is refueled from a barrel or drum this ground wire is nowhere to be seen. Here a jumper cable can be a good safety precaution to assure that any static charge is dissipated before it can build up.
If you use a metal jerrycan with a metal or otherwise conductive funnel (Mr. Funnel) make sure the aircraft, funnel and container are touching each other during the refueling process. Any static buildup is not possible then.
Metal containers dissipate the electric charge easily. Plastic containers usually not, unless they are made of conductive materials. We recommend the use of metal containers with a good jumper wire. It is so much safer.
Static Discharge Reels
At an airport fuel station you will normally find an static discharge reel. Static discharge reels are designed to provide safe and reliable grounding of containers, equipment and vehicles. These reels provide grounding or bonding to prevent static electricity build up in airport sensitive areas.
You will find these reels in many different variants. And using them is easy, grab the large connector and slowly walk to the aircraft while unwinding the reel with the cable. Connect the wire to a conductive place (exhaust will do fine) or to a dedicated aircraft ground connector but not on a painted tiedown ring. Disconnect the ground cable when finished refueling the aircraft.
PS: Do not forget to remove the cable when refueling is finished, you wouldn't be the first...
You talk of an "earthed wire", just where do you think 99.999999999999999% of them are connected?
Your attempted analogy's are FOS. Really desperate as a matter of fact. "Static, Water, Fuel",,,,,,,really,ROFLMAO I'll remember that next time in the pool, or stick my finger in a gas tank.
Here al, it don't get much simpler than this....
Grounding Aircraft
During refueling fuel is transferred from the fuel truck or underground tanks (sometimes above ground) and this process can cause a static charge to build up between the aircraft and fueling device. This is the same principle as walking on a carpet in wintertime and getting a shock from the doorknob when opening a door.
Testing has shown that when people 'feel' this shock the voltage is at least 3500 V. Amperage is very low so no real power is transferred and no harm done, but it can be uncomfortable though. Delicate electronics or aircraft avionics can be 'killed' by voltages much lower than this.
Static Electricity
According to Wikipedia the definition of static electricity is as follows:
"Electrostatics (also known as Static Electricity) is the branch of physics that deals with the forces exerted by a static (i.e. unchanging) electric field upon charged objects. Electrostatics involves the buildup of charge in objects due to contact between (generally) nonconductive surfaces. These charges are generally built up through the flow of electrons from one object to another. These charges then remain in the object until a force is exerted that causes the charges to balance e.g. the familiar phenomenon of a static 'shock' is caused by the neutralization of charge built up in the body from contact with nonconductive surfaces."
Static buildup
It is important to understand how static electricity is build up. As in aircraft operations like refueling this can create dangerous situations. An aircraft flying through the air can also build up static charges. To discharge these build up electrons special devices are attached to ailerons and tail feathers to return these electrons to the surrounding air and they are called 'static wicks'.
Without these so called 'static wicks' an aircraft would experience radio and navigation difficulties due to static discharges on the outside of the aircraft.
Fuel (dis)charging
When an aircraft is refueled fuel is pumped from one container to another and throughout this process the fuel charge level is determined by several factors: pump rate, temperature and humidity. This charge is build up between the two containers. When the charge is high enough to jump between the containers, a spark will occur. If there is a combustible mixture near the spark (above/near the fuel cap) a fire or explosion could happen. And this is the reason why a ground wire is connected from the fuel station to the aircraft whenever fuel is being transferred.
Defueling
There are two area's where a pilot should exercise caution when transferring fuel. The first is when draining an aircraft tank. During this draining fuel is transferred and a charge can build up. Connecting a ground wire from the aircraft to the fuel container makes sure a voltage differential cannot develop and eliminate the change of a spark from aircraft to container.
Just remember, when you are draining fuel, there can be enough air in circulation so that the fuel/air ratio is in the combustible range. And one spark can do the trick..
Fueling
The second problem area is the filling process. Many fuel stations use a ground wire when refilling an aircraft and this is good. But when the aircraft is refueled from a barrel or drum this ground wire is nowhere to be seen. Here a jumper cable can be a good safety precaution to assure that any static charge is dissipated before it can build up.
If you use a metal jerrycan with a metal or otherwise conductive funnel (Mr. Funnel) make sure the aircraft, funnel and container are touching each other during the refueling process. Any static buildup is not possible then.
Metal containers dissipate the electric charge easily. Plastic containers usually not, unless they are made of conductive materials. We recommend the use of metal containers with a good jumper wire. It is so much safer.
Static Discharge Reels
At an airport fuel station you will normally find an static discharge reel. Static discharge reels are designed to provide safe and reliable grounding of containers, equipment and vehicles. These reels provide grounding or bonding to prevent static electricity build up in airport sensitive areas.
You will find these reels in many different variants. And using them is easy, grab the large connector and slowly walk to the aircraft while unwinding the reel with the cable. Connect the wire to a conductive place (exhaust will do fine) or to a dedicated aircraft ground connector but not on a painted tiedown ring. Disconnect the ground cable when finished refueling the aircraft.
PS: Do not forget to remove the cable when refueling is finished, you wouldn't be the first...
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There are variations in wiring practice. In some situations conduit is used; when it is, it is supposed to be grounded. In some cases there may be green equipment ground wires, that are also connected to the neutral bus. I should add that I make no claim to expertise, nor am I making any recommendations about making electrical connections of any sort.