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bobnoffs

Joined: 04 Jul 2012
Posts: 132
Location: northern wi.

Posted: Tue Jul 10, 2012 8:41 am Post subject: grounding procedures

hi all,

 lately i have been filling my plane out of 5 gal. plastic cans and i am finding it not too time consuming. the biggest reason is higher octane mogas than i can get at the airport.

 anyway............i need some advice on grounding.i have a 12 volt pump mounted and it is powered by a battery 20 feet away. i have a handheld switch . i set the plastic can on the table and fuel is transferred thru vinyl tubing. at the airplane end is a metal filter. pumps a gallon a minute. i plan to set up a ground to the exhaust pipe [all tanks are grounded to the engine] but i do not know how to ground   the pump or hoses. any advice would be appreciated.

  bob noffs

  [quote][b]

dave.saylor.aircrafters(a
Guest

Posted: Tue Jul 10, 2012 9:56 am Post subject: grounding procedures

My understanding is that the greatest danger comes from a spark

jumping between the container and the filler neck.



To prevent that, I always very consciously keep the spout in contact

with the filler neck.  When I'm finished filling, I methodically drag

the spout away from the opening before breaking contact.  That way, if

a spark jumps the gap, it doesn't happen near the filler opening.



The worst accident I've heard of (I met the victim) illustrates some

valuable lessons.  He was pouring fuel from a bucket through a funnel

into a wing.  He got the spark/flash, and it wouldn't have been as

horrible if he hadn't instinctively jumped back and spilled the bucket

all over himself.  He's lucky to be alive but he'll never be the same.

 So another point is to use a closed container with a smallish neck

and opening.  That way the flash doesn't ignite the entire volume, and

it doesn't spill as fast if it's dropped.



I've been told that grounding a plastic container is very difficult.

I'm curious to hear what others have to say.



Dave Saylor

831-750-0284 CL

On Tue, Jul 10, 2012 at 9:37 AM, bob noffs <icubob(at)gmail.com> wrote:

 	  Quote: 	
		   hi all,

  lately i have been filling my plane out of 5 gal. plastic cans and i am

 finding it not too time consuming. the biggest reason is higher octane mogas

 than i can get at the airport.

  anyway.............i need some advice on grounding.i have a 12 volt pump

 mounted and it is powered by a battery 20 feet away. i have a handheld

 switch . i set the plastic can on the table and fuel is transferred thru

 vinyl tubing. at the airplane end is a metal filter. pumps a gallon a

 minute. i plan to set up a ground to the exhaust pipe [all tanks are

 grounded to the engine] but i do not know how to ground   the pump or hoses.

 any advice would be appreciated.

  bob noffs

deej(at)deej.net
Guest

Posted: Tue Jul 10, 2012 10:35 am Post subject: grounding procedures

On 07/10/2012 12:37 PM, bob noffs wrote:

i plan to set up a ground to the exhaust pipe

 	  Quote: 	
		   [all tanks are grounded to the engine] but i do not know how to ground 

  the pump or hoses. any advice would be appreciated.


	


Hi Bob,

	If you don't mind spending a small amount of money, might I suggest a

different container?



	The really cheap option if you want to continue using a 5 gallon

container, is an all metal safety can, such as:

http://www.tractorsupply.com/eagle-safety-gas-can-5-gal--3958668



	Drill a hole in the handle and attach a flexible grounding wire (Lowes,

about $19)

http://www.lowes.com/pd_348276-273-5977001_0__?productId=3645156&Ntt=steel+cable&pl=1&currentURL=&facetInfo=

	For something a little more fancy, search for "portable fuel caddy" on

Amazon:



http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=15+gallon+fuel+tank#/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=portable+fuel+caddy&rh=i%3Aaps%2Ck%3Aportable+fuel+caddy

	I ended up buying a 15 gallon metal fuel container from the local

Tractor Supply store, mounted it in my truck, and added one of their 12v

GPI EZ-8 Fuel Pumps, which uses conductive hoses.  I attached a

grounding line between the the tank and pump, and to the aircraft (using

the Lowes steel cable above and a simple spring clamp for the airplane

end), and since the fuel pump uses conductive hoses it also provides

another path for grounding.  I probably have $300 in total for this

setup, but it is arguably as "safe" as the airport's fuel truck in terms

of grounding, and I can use it for all of the toys at home, too.



http://www.tractorsupply.com/gpi-reg-ez-8-fuel-pump-1-10-hp-3-4-in-inlet-3858004



http://www.egascans.com/15-gallon-gas-cans/

	I'd be very concerned using a plastic fuel can, and vinyl transfer

line, neither of which can be grounded safely.



-Dj

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Jul 10, 2012 10:50 am Post subject: grounding procedures

At 11:37 AM 7/10/2012, you wrote:

 hi all,

  lately i have been filling my plane out of 5 gal. plastic cans and i am finding it not too time consuming. the biggest reason is higher octane mogas than i can get at the airport.

  anyway.............i need some advice on grounding.i have a 12 volt pump mounted and it is powered by a battery 20 feet away. i have a handheld switch . i set the plastic can on the table and fuel is transferred thru vinyl tubing. at the airplane end is a metal filter. pumps a gallon a minute. i plan to set up a ground to the exhaust pipe [all tanks are grounded to the engine] but i do not know how to ground   the pump or hoses. any advice would be appreciated.



    I had this conversation with fellow who stopped in

    at our airport for fuel way back when. He was flying

    one of the Rutan Ez airplanes (all plastic) and as

    I fueled him, he expressed concerns about vapor fires

    while transferring fuel in the hangar next to his house.



    I suggested that one could take a cue from the heavy

    iron airplanes fitted with single point fueling ports.

    You can avoid vapor/spillage issues entirely when 

    access to the tanks is fitted with a auto shut-off quick-

    connect like those used in hydraulic systems:



   



    The fitting might even replace the tank's water drains.

    You could craft a water-inspection tool to access this port

    and fit your fuel transfer hose with the mating fitting.

    Remove the fuel cap to fill. You can watch down the filler

    cap to effect the appropriate time to shut off flow but

    without placing anything conductive and/or static prone in

    the vicinity of the filler cap.



    He thought he would do that for his airplane . . . but never

    saw him again or got any feedback on the technique. Seems

    like one could fill a tank with zero chance for spilled fuel

    and/or generation of sparks near the vented vapors.



    If it's good for a Boeing or a Hawker, it might be just as

    good for an RV.



 

   Bob . . .    [quote][b]

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Tue Jul 10, 2012 11:21 am Post subject: grounding procedures

This is a very worth while thread.... as some time or another, fueling with 

portable containers can bite you...

Some suggestions to add to others replying.....



* be especially aware of the static spark problem on hotter, drier days..

* the flowing fuel itself generates static voltage, again, dry days are 

worse.

* some insert a type of copper ground wire inside the fueling line itself so 

that it is in contact with the fuel from end to end; plastic container to 

funnel and aircraft.

* plastic containers as mentioned before are the worst for fueling when they 

are used directly on the wing pouring.  If on the end of an extended fuel 

hose via a pump, that is different but, still a problem as the vinyl hose 

could easily build up a static charge.  That is where the copper wire 

running the whole length inside the hose would help drain off any building 

charge.

* again, as mentioned earlier it is important to figure a method to ground 

the fuel contain, hoses, etc. to the tank being filled.  If  done properly, 

no static of any consequence should build to the point of a discharge.



Hopefully, others will add to and correct this list.



I also have a personal example of what this kind of accident can do.  A 

local gal, who was a 1st class ultralights pilot and instructor, was filling 

her wing tank via a plastic container on a warm, dry day in Oregon.  A spark 

jumped, fire ensued instantly and she too accidently got fuel splashed on 

her as she jumped down.  Ultralights was a total loss and she spent years 

trying to get her body damage corrected with surgery.  Dave

---

bobnoffs

Joined: 04 Jul 2012
Posts: 132
Location: northern wi.

Posted: Tue Jul 10, 2012 12:21 pm Post subject: grounding procedures

i am thinking of pushing a copper wire thru the vinyl hose from each end [an end in the can and an end in the aircraft] and when i get to the metal pump i am thinking i can clamp the wire between the vinyl tube wall and the metal barb on the pump. the pump will then be grounded. also ground the plane. how bout that?

  bob noffs

On Tue, Jul 10, 2012 at 2:20 PM, David Lloyd <skywagon(at)charter.net (skywagon(at)charter.net)> wrote:

[quote] --> AeroElectric-List message posted by: "David Lloyd" <skywagon(at)charter.net (skywagon(at)charter.net)>

 

 This is a very worth while thread.... as some time or another, fueling with portable containers can bite you...

 Some suggestions to add to others replying.....

 

 * be especially aware of the static spark problem on hotter, drier days..

 * the flowing fuel itself generates static voltage, again, dry days are worse.

 * some insert a type of copper ground wire inside the fueling line itself so that it is in contact with the fuel from end to end; plastic container to funnel and aircraft.

 * plastic containers as mentioned before are the worst for fueling when they are used directly on the wing pouring.  If on the end of an extended fuel hose via a pump, that is different but, still a problem as the vinyl hose could easily build up a static charge.  That is where the copper wire running the whole length inside the hose would help drain off any building charge.

  * again, as mentioned earlier it is important to figure a method to ground the fuel contain, hoses, etc. to the tank being filled.  If  done properly, no static of any consequence should build to the point of a discharge.

  

 Hopefully, others will add to and correct this list.

 

 I also have a personal example of what this kind of accident can do.  A local gal, who was a 1st class ultralights pilot and instructor, was filling her wing tank via a plastic container on a warm, dry day in Oregon.  A spark jumped, fire ensued instantly and she too accidently got fuel splashed on her as she jumped down.  Ultralights was a total loss and she spent years trying to get her body damage corrected with surgery.  Dave

  

 

 ---

peter(at)sportingaero.com
Guest

Posted: Tue Jul 10, 2012 1:03 pm Post subject: grounding procedures

Hi Bob,

     

     I has a similar set up a while ago. I believe the danger is static     produced by the flow of fuel through the plastic hose, with a charge     building up on the nozzle jumping to the airplane and igniting and     vapour near the filler neck.

     

     I used a piece of copper plumbing pipe as a filler spout and     soldered some thick speaker cable to it. I connected that to the     airplane exhaust to make the airplane and filler spout at the same     potential. I also used steel fuel cans and ran the speaker wire.     wound around the pipe, back to the filler can and connected with a     large croc clip. The pump motor was also hooked up to avoid any     static build up. You can also connect the whole lot to a steel stake     in the ground if you really want to.

     

     I used a small 7ah battery to power the whole thing - it would pump     5gals in about 3 minutes. It worked quite well.

     

     Hope this helps, Peter

     

     

     On 10/07/2012 17:37, bob noffs wrote:

     

     [quote]       hi all,

        lately i have been filling my plane out of 5 gal. plastic         cans and i am finding it not too time consuming. the biggest         reason is higher octane mogas than i can get at the airport.

        anyway.............i need some advice on grounding.i have a         12 volt pump mounted and it is powered by a battery 20 feet         away. i have a handheld switch . i set the plastic can on the         table and fuel is transferred thru vinyl tubing. at the airplane         end is a metal filter. pumps a gallon a minute. i plan to set up         a ground to the exhaust pipe [all tanks are grounded to the         engine] but i do not know how to ground   the pump or hoses. any         advice would be appreciated.

        bob noffs

        	  Quote: 	
		  

	
     [b]

ftyoder(at)yoderbuilt.com
Guest

Posted: Tue Jul 10, 2012 1:07 pm Post subject: grounding procedures

Don't use a plastic gas can! Replace it with a  steel one. You can't afford to use cheap parts, equipment, on airplanes.  

  

 Also, if you are flying a composite plane, the the  gas cap filler ring is not grounded unless the builder ran a ground wire to the  ships ground. When filling from a steel can, touch the nozzle to the ring  and your body is ground to earth. Do this even when filling off a truck or fuel  island. You only get one chance!

 [quote]   ---

jbr79r(at)yahoo.com
Guest

Posted: Tue Jul 10, 2012 2:01 pm Post subject: grounding procedures

Smoe thing that was determined awhile back  by the CAFE foundation was that the best way to get rid of static was to wipe around the fuel cap with a damp rag before fueling.  This is what i do with my Glasair

Jim



 

James Robinson

Glasair lll  N79R

Spanish Fork UT  U77

        From: bob noffs <icubob(at)gmail.com>

 To: aeroelectric-list(at)matronics.com 

 Sent:  Tuesday, July 10, 2012 1:19 PM

 Subject: Re: grounding procedures

  

 

 i am thinking of pushing a copper wire thru the vinyl hose from each end [an end in the can and an end in the aircraft] and when i get to the metal pump i am thinking i can clamp the wire between the vinyl tube wall and the metal barb on the pump. the pump will then be grounded. also ground the plane. how bout that?

  bob noffs

On Tue, Jul 10, 2012 at 2:20 PM, David Lloyd <skywagon(at)charter.net (skywagon(at)charter.net)> wrote:

[quote] --> AeroElectric-List message posted by: "David Lloyd" <skywagon(at)charter.net (skywagon(at)charter.net)>

 

 This is a very worth while thread.... as some time or another, fueling with portable containers can bite you...

 Some suggestions to add to others replying.....

 

 * be especially aware of the static spark problem on hotter, drier days..

 * the flowing fuel itself generates static voltage, again, dry days are worse.

 * some insert a type of copper ground wire inside the fueling line itself so that it is in contact with the fuel from end to end; plastic container to funnel and aircraft.

 * plastic containers as mentioned before are the worst for fueling when they are used directly on the wing pouring.  If on the end of an extended fuel hose via a pump, that is different but, still a problem as the vinyl hose could easily build up a static charge.  That is where the copper wire running the whole length inside the hose would help drain off any building charge.

  * again, as mentioned earlier it is important to figure a method to ground the fuel contain, hoses, etc. to the tank being filled.  If  done properly, no static of any consequence should build to the point of a discharge.

  

 Hopefully, others will add to and correct this list.

 

 I also have a personal example of what this kind of accident can do.  A local gal, who was a 1st class ultralights pilot and instructor, was filling her wing tank via a plastic container on a warm, dry day in Oregon.  A spark jumped, fire ensued instantly and she too accidently got fuel splashed on her as she jumped down.  Ultralights was a total loss and she spent years trying to get her body damage corrected with surgery.  Dave

  

 

 ---

jay(at)horriblehyde.com
Guest

Posted: Tue Jul 10, 2012 11:56 pm Post subject: grounding procedures

Hi there Bob,

 

The point of grounding is to ensure that all items in the fuelling process are at the same potential; no potential difference then no spark between items; no spark, no BOOM! (sometimes started off by a small and seemingly insignificant announcement like, ‘oh, damn!’)

 

You get a potential difference between items because of static build up, perhaps a bit of capacitance, and from the flow of the fuel itself (working similarly to you rubbing a jersey against your car in dry air- static build up).  Connect a thin wire (even 22AWG would be fine) from the negative of your external pump battery and run it along the fuel tubing to the metal filter- and also back to your plastic can.  Connect it electrically to the filter and continue along to the end of the tube where it goes into the tank.  Put a crocodile clip on the end and connect that to the tank inlet- also put a croc clip at the plastic can end and clip it to the can.  You can also run a lead to the exhaust but essentially the only place that you are concerned about is where the fuel could ignite- right at the filler.

By running that wire all along the fuel line, from source to delivery point, each item is held at the same potential; no potential difference, no spark.

Yes, I know that the refuelling can is plastic, but plastic can still build up a static charge.

As an additional precaution you could also connect the battery negative to a metal plate that it lies on top of, but, that can be quite meaningless in terms of earthing/ grounding the system, depending on what surface this is all sitting on.

Better to bring the whole system to voltage equality by holding the metal filter when you approach the aircraft and then touch the wing with your palm.  Any potential difference will be balanced and you can now connect the delivery side to the tank inlet comfortably.

 

Jay

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of bob noffs

Sent: 10 July 2012 06:38 PM

To: aeroelectric list

Subject: grounding procedures



 

hi all,



 lately i have been filling my plane out of 5 gal. plastic cans and i am finding it not too time consuming. the biggest reason is higher octane mogas than i can get at the airport.



 anyway.............i need some advice on grounding.i have a 12 volt pump mounted and it is powered by a battery 20 feet away. i have a handheld switch . i set the plastic can on the table and fuel is transferred thru vinyl tubing. at the airplane end is a metal filter. pumps a gallon a minute. i plan to set up a ground to the exhaust pipe [all tanks are grounded to the engine] but i do not know how to ground   the pump or hoses. any advice would be appreciated.



 bob noffs

 	  Quote: 	
		    [/b][/b][/b][b]http://www.matronics.com/Navigator?AeroElectric-List[b] 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
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7 	  Quote: 	
		   	
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9

  [quote][b]

jay(at)horriblehyde.com
Guest

Posted: Wed Jul 11, 2012 12:01 am Post subject: grounding procedures

That’ll work.

 

Jay

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of bob noffs

Sent: 10 July 2012 10:19 PM

To: aeroelectric-list(at)matronics.com

Subject: Re: grounding procedures



 

i am thinking of pushing a copper wire thru the vinyl hose from each end [an end in the can and an end in the aircraft] and when i get to the metal pump i am thinking i can clamp the wire between the vinyl tube wall and the metal barb on the pump. the pump will then be grounded. also ground the plane. how bout that?



 bob noffs



On Tue, Jul 10, 2012 at 2:20 PM, David Lloyd <skywagon(at)charter.net (skywagon(at)charter.net)> wrote:

--> AeroElectric-List message posted by: "David Lloyd" <skywagon(at)charter.net (skywagon(at)charter.net)>



This is a very worth while thread.... as some time or another, fueling with portable containers can bite you...

Some suggestions to add to others replying.....



* be especially aware of the static spark problem on hotter, drier days..

* the flowing fuel itself generates static voltage, again, dry days are worse.

* some insert a type of copper ground wire inside the fueling line itself so that it is in contact with the fuel from end to end; plastic container to funnel and aircraft.

* plastic containers as mentioned before are the worst for fueling when they are used directly on the wing pouring.  If on the end of an extended fuel hose via a pump, that is different but, still a problem as the vinyl hose could easily build up a static charge.  That is where the copper wire running the whole length inside the hose would help drain off any building charge.

* again, as mentioned earlier it is important to figure a method to ground the fuel contain, hoses, etc. to the tank being filled.  If  done properly, no static of any consequence should build to the point of a discharge.



Hopefully, others will add to and correct this list.



I also have a personal example of what this kind of accident can do.  A local gal, who was a 1st class ultralights pilot and instructor, was filling her wing tank via a plastic container on a warm, dry day in Oregon.  A spark jumped, fire ensued instantly and she too accidently got fuel splashed on her as she jumped down.  Ultralights was a total loss and she spent years trying to get her body damage corrected with surgery.  Dave

---

raymondj(at)frontiernet.n
Guest

Posted: Wed Jul 11, 2012 12:32 am Post subject: grounding procedures

Bob,



Another thing to consider is what happens if/when the pump fails in some 

way.  Is it possible for the electrons to find a path that would cause a 

problem?  I don't have an answer, but it seems like another possible way 

for bad things to happen.



Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine

On 07/10/2012 03:19 PM, bob noffs wrote:

[quote] i am thinking of pushing a copper wire thru the vinyl hose from each end

 [an end in the can and an end in the aircraft] and when i get to the

 metal pump i am thinking i can clamp the wire between the vinyl tube

 wall and the metal barb on the pump. the pump will then be grounded.

 also ground the plane. how bout that?

   bob noffs



 On Tue, Jul 10, 2012 at 2:20 PM, David Lloyd <skywagon(at)charter.net

 <mailto:skywagon(at)charter.net>> wrote:



     

     <skywagon(at)charter.net <mailto:skywagon(at)charter.net>>



     This is a very worth while thread.... as some time or another,

     fueling with portable containers can bite you...

     Some suggestions to add to others replying.....



     * be especially aware of the static spark problem on hotter, drier

     days..

     * the flowing fuel itself generates static voltage, again, dry days

     are worse.

     * some insert a type of copper ground wire inside the fueling line

     itself so that it is in contact with the fuel from end to end;

     plastic container to funnel and aircraft.

     * plastic containers as mentioned before are the worst for fueling

     when they are used directly on the wing pouring.  If on the end of

     an extended fuel hose via a pump, that is different but, still a

     problem as the vinyl hose could easily build up a static charge.

       That is where the copper wire running the whole length inside the

     hose would help drain off any building charge.

     * again, as mentioned earlier it is important to figure a method to

     ground the fuel contain, hoses, etc. to the tank being filled.  If

       done properly, no static of any consequence should build to the

     point of a discharge.



     Hopefully, others will add to and correct this list.



     I also have a personal example of what this kind of accident can do.

       A local gal, who was a 1st class ultralights pilot and instructor,

     was filling her wing tank via a plastic container on a warm, dry day

     in Oregon.  A spark jumped, fire ensued instantly and she too

     accidently got fuel splashed on her as she jumped down.  Ultralights

     was a total loss and she spent years trying to get her body damage

     corrected with surgery.  Dave

     ---

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jul 11, 2012 8:13 am Post subject: grounding procedures

At 03:31 AM 7/11/2012, you wrote:

 	  Quote: 	
		  



Bob,



Another thing to consider is what happens if/when the pump fails in 

some way.  Is it possible for the electrons to find a path that 

would cause a problem?  I don't have an answer, but it seems like 

another possible way for bad things to happen.



Raymond Julian

Kettle River, MN.


	


   The fuel is itself a non-conductor so things happening

   at the input end of a hose are not electrically relevant

   to things that occur at the other end. Static electricity

   is only loosely related to power electricity. While the

   earliest investigations into the nature of electrons involved

   the migration of electrons from one surface to another

   as static sources, none of these phenomenon produced

   a practical power sources.



   Static electricity is a byproduct of motion between

   two substances with dissimilar affinities for hanging

   onto their electrons. The substances need not be conductive.

   You can rub a balloon on cat's fur and generate an observable

   effect of electron migration in spite of the fact that

   the two materials are exceedingly poor conductors.



   Hence, the sources for static generation are limitless.

   The risks are obviously limited to the small sphere

   of conditions existing in the immediate vicinity of

   any exposed fuel, oxygen and potential ignition source.



   Risks are reduced when any number of the three

   components are removed from the mix. Single point

   fueling fixtures remove exposed fuel and air

   sources. So even if drew a healthy arc between

   the two fittings as they are mated or de-mated,

   risks for escalating combustion are zero.



   If your intent is to stick a delivery device into

   an open fuel tank, then care must be made to control

   the greatest risks (1) spillage and (2) ignition

   source that might ignite vapors. The whole grounding

   issue goes to control of ignition source. This

   can be vexing for combinations of plastic airplanes,

   non-conductive hoses, high rates of fuel flow, etc.



   Filling from a hand-held plastic fuel can does

   not represent a strong potential for an ignition

   source. Flow rates are low and there's no gathering

   point for a build-up of arc potential (like your

   fingertip approaching the door handle). Instances

   of fire when filling lawn mowers were the result

   of added risk for spillage over a hot engine that

   made the vapors hype-sensitive to tiny sparks

   that are happening all the time all around us

   anytime two non conductors move in close proximity

   to each other.



   The strongest prophylactic for unintended

   combustion has more to do with careful avoidance

   of spillage and high flow rates into the tank

   (through the same kind of hose used to put a

   full load on a King Air in minutes). Those same

   hoses MIGHT be a conductor of differential static

   potential between two LARGE capacitors . . . the surface

   of an airplane and the surfaces of a fuel truck.

   High flow rates into the tank cause both increased

   intensity of static buildup and outflow of vapors

   from the tank's heads pace.



   Adding a 'ground wire' inside a non-conducting fuel

   hose only serves to bring a connection from the static

   capacity of the delivery system out to the end of the

   hose. Adding such wire only INCREASES the need for grounding

   the delivery system to the airframe before approaching

   the filler neck with the end of the hose.



   Risks for a hand-held pour from a plastic 'can' is

   exceedingly low.

   Bob . . .

raymondj(at)frontiernet.n
Guest

Posted: Wed Jul 11, 2012 9:52 am Post subject: grounding procedures

Bob,



I was thinking more along the lines of a failure of the electrical 

portion of the pump resulting in the pump body being energized and the 

electrons moving into the system designed to handle static charge. 

Similar to kind of event that the grounding wire in a 3 prong plug is 

designed to manage.



Just a thought.



Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine

On 07/11/2012 11:12 AM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   

 <nuckolls.bob(at)aeroelectric.com>



 At 03:31 AM 7/11/2012, you wrote:

> 

>

> Bob,

>

> Another thing to consider is what happens if/when the pump fails in

> some way.  Is it possible for the electrons to find a path that would

> cause a problem?  I don't have an answer, but it seems like another

> possible way for bad things to happen.

>

> Raymond Julian

> Kettle River, MN.



    The fuel is itself a non-conductor so things happening

    at the input end of a hose are not electrically relevant

    to things that occur at the other end. Static electricity

    is only loosely related to power electricity. While the

    earliest investigations into the nature of electrons involved

    the migration of electrons from one surface to another

    as static sources, none of these phenomenon produced

    a practical power sources.



--------------------------- SNIP -----------------------------------
	




 	  Quote: 	
		      Bob . . .

bobnoffs

Joined: 04 Jul 2012
Posts: 132
Location: northern wi.

Posted: Wed Jul 11, 2012 4:27 pm Post subject: grounding procedures

got a lot of good info from all the replies. i think i will go with the wire in the tube only because it is less likely to mar a finish. that wire will connect to metal tube in plastic can, the metal pump and the metal fuel filter on the airplane end. a ground wire from the exhaust pipes to the metal pump should make a spark impossible. am i missing something? the only other thing i can think of is to run a wire from the pump to the earth. would this serve any purpose?

  bob noffs

On Wed, Jul 11, 2012 at 12:51 PM, rayj <raymondj(at)frontiernet.net (raymondj(at)frontiernet.net)> wrote:

 [quote]--> AeroElectric-List message posted by: rayj <raymondj(at)frontiernet.net (raymondj(at)frontiernet.net)>

  

 Bob,

 



 I was thinking more along the lines of a failure of the electrical portion of the pump resulting in the pump body being energized and the electrons moving into the system designed to handle static charge. Similar to kind of event that the grounding wire in a 3 prong plug is designed to manage.

  

 Just a thought.

 

 Raymond Julian

 Kettle River, MN.

 



 "And you know that I could have me a million more friends,

 and all I'd have to lose is my point of view." - John Prine

 

 



 On 07/11/2012 11:12 AM, Robert L. Nuckolls, III wrote:

  	  Quote: 	
		   --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"

 <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

 

 At 03:31 AM 7/11/2012, you wrote:

  	  Quote: 	
		   --> AeroElectric-List message posted by: rayj <raymondj(at)frontiernet.net (raymondj(at)frontiernet.net)>

 

 Bob,

 

 Another thing to consider is what happens if/when the pump fails in

 some way.  Is it possible for the electrons to find a path that would

 cause a problem?  I don't have an answer, but it seems like another

 possible way for bad things to happen.

 

 Raymond Julian

 Kettle River, MN.

 	
 

    The fuel is itself a non-conductor so things happening

    at the input end of a hose are not electrically relevant

    to things that occur at the other end. Static electricity

    is only loosely related to power electricity. While the

    earliest investigations into the nature of electrons involved

    the migration of electrons from one surface to another

    as static sources, none of these phenomenon produced

    a practical power sources.

 

 	


 --------------------------- SNIP -----------------------------------

 

  	  Quote: 	
		      Bob . . .

 

 

 

 

 

 	
 

 

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[b]

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jul 11, 2012 4:44 pm Post subject: grounding procedures

At 12:51 PM 7/11/2012, you wrote:

 	  Quote: 	
		  



Bob,



I was thinking more along the lines of a failure of the electrical 

portion of the pump resulting in the pump body being energized and 

the electrons moving into the system designed to handle static 

charge. Similar to kind of event that the grounding wire in a 3 

prong plug is designed to manage.


	


    Grounds for the purpose of creating a safe-path

    for internal ground faults within a device

    are not expected to carry any great amount of

    current for long nor does the voltage during

    fault clearance time exceed that of the system . .

    I presume you have a 12vdc pump.



    Grounding of two "capacitors" (vehicle and airplane)

    to each other to prevent a difference in potential

    at the filler cap between nozzle and cap rim should

    be independent of and ground system provided for

    electrical fault clearance inside the pump motor.

    Single-point grounds for airplane and pump system might

    be the fuel truck chassis or even a grounding lug

    on the ramp (we had them all over the floor in the

    Experimental Flight Test Hangar) but you'd want

    to avoid daisy-chaining grounds.



    If the pump has been approved for fuel transfers

    then seals between fluid path and motor internals

    are pretty good . . . if non-existent (magnetic

    drive). The motor itself is probably qualified to

    high levels of explosion proof-ness (will totally

    contain products of combustion even if a stoichiometric

    mixture should become ignited within).



    The difference in voltage to be bled off is in the

    gap between fuel nozzle and the tank opening. This

    is best handled by a ground wire between these two

    points secured before the fuel tank is uncapped.

    The same ground is not removed before the cap is

    replaced and any spills wiped up. Nothing more exotic

    is necessary or useful. If it's a plastic airplane,

    then no 'grounding' is possible or necessary.



    This is an electro-static argument between your fuel

    delivery exit point and fuel tank entrance. That's where

    the oxygen-fuel source resides and where the ignition

    source must be prevented. All else is immaterial.



   Bob . . .

bobnoffs

Joined: 04 Jul 2012
Posts: 132
Location: northern wi.

Posted: Wed Jul 11, 2012 5:47 pm Post subject: grounding procedures

soooooooooooo  my tanks are grounded to my engine. am i safe to attach a wire from my fuel nozzle to my exhaust pipe or does the wire need to go to the tank filler neck? [that doesn't make sense to me]

  bob noffs

  

On Wed, Jul 11, 2012 at 7:30 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

 [quote]--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

  



 At 12:51 PM 7/11/2012, you wrote:

 

 	  Quote: 	
		   --> AeroElectric-List message posted by: rayj <raymondj(at)frontiernet.net (raymondj(at)frontiernet.net)>

 

 Bob,

 



 I was thinking more along the lines of a failure of the electrical portion of the pump resulting in the pump body being energized and the electrons moving into the system designed to handle static charge. Similar to kind of event that the grounding wire in a 3 prong plug is designed to manage.

  

	
 

    Grounds for the purpose of creating a safe-path

    for internal ground faults within a device

    are not expected to carry any great amount of

    current for long nor does the voltage during

    fault clearance time exceed that of the system . .

    I presume you have a 12vdc pump.

 

    Grounding of two "capacitors" (vehicle and airplane)

    to each other to prevent a difference in potential

    at the filler cap between nozzle and cap rim should

    be independent of and ground system provided for

    electrical fault clearance inside the pump motor.

    Single-point grounds for airplane and pump system might

    be the fuel truck chassis or even a grounding lug

    on the ramp (we had them all over the floor in the

    Experimental Flight Test Hangar) but you'd want

    to avoid daisy-chaining grounds.

 

    If the pump has been approved for fuel transfers

    then seals between fluid path and motor internals

    are pretty good . . . if non-existent (magnetic

    drive). The motor itself is probably qualified to

    high levels of explosion proof-ness (will totally

    contain products of combustion even if a stoichiometric

    mixture should become ignited within).

 

    The difference in voltage to be bled off is in the

    gap between fuel nozzle and the tank opening. This

    is best handled by a ground wire between these two

    points secured before the fuel tank is uncapped.

    The same ground is not removed before the cap is

    replaced and any spills wiped up. Nothing more exotic

    is necessary or useful. If it's a plastic airplane,

    then no 'grounding' is possible or necessary.

 

    This is an electro-static argument between your fuel

    delivery exit point and fuel tank entrance. That's where

    the oxygen-fuel source resides and where the ignition

    source must be prevented. All else is immaterial.

 

 

 

   Bob . . . 

 

 ====================================

 -List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

 ====================================

 http://forums.matronics.com

 ====================================

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ====================================

 

 

 

 



[b]

toddheffley

Joined: 24 Mar 2010
Posts: 8
Location: Fort Worth Texas

Posted: Thu Jul 12, 2012 1:44 am Post subject: Re: grounding procedures

I was always doubted the importance of using a metal funnel until I fueled our champ on a dry day with a large plastic funnel.  I was standing in the tire so I was also insulated.  A charge built up strong enough to attract the hair on my arm to stand up toward the cowl. No Harm, No Foul. It was a warning to alter my behaviour before a really bad indecent occurred.



todd

_________________
WWW.toddheffley.com
www.theinterconnectco.com for lighting products
AV-TS.com for Jet Aircraft Test Equipment

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jul 12, 2012 7:52 am Post subject: grounding procedures

At 08:46 PM 7/11/2012, you wrote:

  	  Quote: 	
		  soooooooooooo  my tanks are grounded to my engine. am i safe to attach a wire from my fuel nozzle to my exhaust pipe or does the wire need to go to the tank filler neck? [that doesn't make sense to me]

   bob noffs 	


   The word "grounded" is poorly understood and

   in this discussion poorly used. As we've studied

   in other conversations, having "lots of grounds"

   can be deleterious to system performance in terms

   of noised conducted from one system to another.



   This static charge thing, like most studies of

   physics is an energy management issue. We have

   an energy source (motion between dissimilar

   materials in close proximity), energy storage

   (capacitance - proportional to surface area

   of mass carrying a charge), potential pathways

   for the two masses to exchange levels of charge,

   series resistance of those pathways, and finally

   open air gaps in the discharge path were a spark

   might form that is surrounded by a flammable mixture.



   The legacy hazard from which all these discussions

   arise are grounded in the management of charges

   stored on LARGE surface areas (air transport/military

   aircraft and fuel trucks or underground fueling

   systems. BIG numbers in terms of potential energy

   to be released in that worrisome air-gap.



   I'll refer readers to a couple of documents I've

   posted to Aeroelectric.com at



  http://tinyurl.com/7et4jj5



   These two documents speak to 'modeling' the human

   body for the purposes of carrying out standardized

   tests for ESD vulnerability. Given the surface

   area of adult humans to be on the order of 1.5 to

   2 square meters, they are 'modeled' as 100 picofarad

   capacitors. Further the ability to conduct a charge

   off that 'capacitor' is limited by the average

   conductivity of the body between the center of charge

   and a discharge point (finger tip) which is modeled

   with a 1500 ohm resistor. Now, charge the capacitor up

   to various voltages up to 15,000 volts and you have

   a repeatable means for generating antagonistic stresses

   on some device to be tested for ESD immunity.



   The machine model is similar but 200 picofarads and

   1 ohm of series resistance. I.e., more surface area

   and better conductivity.



   Now, what might we think the model would be for a

   B-747?  LOTS of surface area and metallic structure

   which provides very low series resistance. Static

   charges between large masses can knock you on your

   can.



   Getting back to filling puddle jumpers from gas

   cans or even fuel trucks . . .



   The model for a plastic airplane might consider

   a surface area on the order of 1000 picofarads

   but what's the series resistance? It's an insulator

   with hing series resistance. In my studies

   with ESD testing I discovered that the WORST case

   instances for testing to human body model (15KV)

   VERY LITTLE of the potential energy was dissipated

   at the victim . . . that 1500 ohm resistor dissipates

   90 plus % of the energy. When dealing with things

   like metal airplanes and fuel trucks, the machine

   models are in force with something on the order of 1000-2000

   pf each and VERY LOW series resistance. Connecting

   them together before dragging out the hose MAY

   NOT dissipate all their charges to zero . . . but it does

   bring them TOGETHER in terms of voltage thus ELIMINATING

   a potential of spark through a low series resistance.



   I forget the structure of the airplane that started

   this discussion but I think we were talking about a

   non-conductive hose fitted to a fuel transfer pump.

   In this instance, ADDING a low series resistance

   conductor along the hose length only increases potential

   for energy dissipation in a spark at the end of the

   hose. Bringing a potential charge on the airplane and

   fuel storage containers together is 99.9% of the

   safety issue. Having a very large series resistance

   in the potential ignition discharge path is another

   risk mitigation move.



   I've been reading lengthy discussions about fuel

   transfer safety on OBAM aircraft for decades sprinkled

   with hangar tales and speculative advice . . .

   but never have I seen a study of the physics that

   underlie the potential for an ignition accident.



   Just consider the millions of cars that get fueled

   by ding-a-ling drivers every day without blowing 

   themselves up. Yes, there are the expected 'news'

   stories and security camera videos about the

   occasional filling station fire. Shucks even the

   Mytbusters made a show out of the notion that cell

   phones can trigger explosions or fire.



   But even the hallowed Mythbusters failed to 

   mention the physics . . . much less consider how

   HARD it is to initiate an explosion under laboratory

   conditions (re: explosion proofing tests on motors

   we used to build at Electro-Mech).



   Bottom line is that if you don't have a means to

   bring the surface charge of a container to the same potential

   as the surface of your airplane, then the SAME limitation

   is in force for causing a spark at the opening of your

   filler cap. I.e. if you can't get a spark at the connection

   of a potential equalization wire at the exhaust stack of

   your engine, you won't get a spark at the filler cap

   either. Potentials generated by flowing fuel are

   similarly limited in their ability to conduct the

   charge to a 'arc gap'. Consider that the fuel

   is in constant motion so any charge the liquid carries

   is being continuously dumped into the tank . . .

   Where is the 'conductor' that's going to bring

   that charge to an arc gap? Flammable hydrocarbons

   heavier than gasolines are used as medium for

   cooling and INSULATOR in high voltage transformers and

   capacitors.



   Where does the energy come from, where is it stored,

   what is the potential equalization path, what is

   the series resistance of that path, is it possible

   or even NECESSARY to effect an equalization of

   potentials at some point AWAY from the filler cap?



   Bottom line is that using the same care you would

   exercise in filling your car, boat or lawn mower will

   suffice to secure your healthy use of that machine.

   Adding prophylactic features willy-nilly without

   understanding the physics and design goals may

   increase risk as opposed to reducing it. If the

   truth were known as to root cause for the anecdotal

   fuel transfer fires, most if not all would be due

   to carelessness.



 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jul 12, 2012 8:06 am Post subject: grounding procedures

At 04:44 AM 7/12/2012, you wrote:

 	  Quote: 	
		  

<public(at)toddheffley.com>



I was always doubted the importance of using a metal funnel until I 

fueled our champ on a dry day with a large plastic funnel.  I was 

standing in the tire so I was also insulated.  A charge built up 

strong enough to attract the hair on my arm to stand up toward the 

cowl. No Harm, No Foul. It was a warning to alter my behaviour 

before a really bad indecent occurred.



todd


	




   Sure, while funnels provide a handy tool for control

   of the flow of liquid, they add a piece of 'loose gear'

   to the mix and expose a the surface of liquid flow

   to the air (and funnel surface). The former increases

   local concentration of hazardous vapor, the later increases

   potential for building an electro-static charge (motion

   of dissimilar materials in close proximity). Your body

   became yet another surface on which generated charges

   could collect. A hair-raising experience both literally

   and for consideration of increased risk.



   99.999+ of fuel transfers in the world are effected with

   a nozzle extend into the fuel storage system. Most are

   metallic and in contact with each other. The only

   thing you can do to IMPROVE on this combination would

   be to close the liquid motion off from the air and

   potential for spillage by using some feature like I

   suggested yesterday.



   As a general rule, I would avoid the use of funnels.

   Yeah, Lindbergh used 'em . . . even lined the funnel

   with a chamois to absorb water. We don't read much

   about aviators of yor setting themselves on fire

   during a fueling accident but the risks were demonstrably

   great.



   Bob . . .

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