External battery jumpers - question

[Pinecone]

43 minutes ago, PeteMc said:

"Can" or did you mean "...can't be used without the nozzle touching the tank/filler metal."   In my Mooney and all the Cessnas and Pipers I flew early on, there's no way I could guarantee not touching the metal. 

But there is also no way to guarantee that you WILL touch the metal.  And if you don't, while pumping, you can get a spark.

[Pinecone]

1 hour ago, Shadrach said:

Not sure why this matters. If there is a charge, isn't it going to spark before the nozzle is grounded to the filler neck. I thought the point of external grounding was to discharge in an area away from fuel vapor.

There may be a small spark when you first make contact. But the fuel flowing through the hose will also generate a charge for later.

[GeeBee]

Static discharge from fueling is a very big deal. Years ago I had one of the early bed liners and I had a 5 gallon metal jerry can in the back. I pulled up to the pumps, and being lazy left the can in the truck while I fueled it. I can remember to this day, the spark, it jumped the gap between the nozzle and the can and that millisecond was enough for me to say "OH excrement!" and for me to move my face back before it went WOOOSH! Fortunately I dropped the nozzle dead, and grabbed a nearby extinguisher and put out the fire. I was several weeks later interviewed by the NFPA who informed me bedliners were a "new" problem. They were talking to manufacturers about inserting carbon as a conductor into the plastics mix as tires have to aid in grounding.

I used to be a line boy and was always very careful about loading my tankers from the bulk facility as well as grounding planes, but a moment of laziness and thoughtlessness  caught me with this jerry can.

 

[A64Pilot]

2 hours ago, Pinecone said:

But the fuel flowing through the hose will also generate a charge for later.

This, and I’ve found maybe not all fuel hoses have the bonding wire.

I was looking at a hose reel with 50’ hose on it for my tank on Amazon and asked if the hose had the grounding wire and was told it didn’t. Of course person telling me that could have been wrong, I would have thought that would be required to be a fuel hose.

Its real easy to find out, just take a multimeter and check for continuity between the metal ends