Fuel Tank Ground

[Bcone1381]

Today as I am reading thru part of Eric Newtons Bearhawk Builder's Manual. (Specifically the Volume 1 Wing Manual, part 8, p.13) Eric Newton adds a grounding lug to the fuel tank to facilitate grounding the tank to the wing because he uses rubber as a cushion between the fuel tank straps and the tank.

This is the first I've thought of grounding the tank.Are others grounding the fuel tank? If so, by what method?

I am thinking maybe an AN472 aluminum loop clamp around the AL fuel line near the tank. Then a wire with a ring terminal on each end to ground the loop clamp to a rib. Is there a industry standard that demands it be attached directly to the tank?

[jaredyates]

I use electrically conductive fuel lines, does that count?

[Ray Strickland]

Brooks,
Yes, ground those tanks. I used a method similar to what you propose.

[Isilverone]

Ya the MDRA inspector in Canada says it’s mandatory. I used a regular 10ga wire, pulled 8” of the cover off one end and used a foil tape to adhere it to the tank

[zkelley2]

Ya fuel tanks need to be grounded to the aircraft, otherwise that grounding wire you attach when you fuel is doing nothing to prevent a spark at the tank hole when you bring the nozzle up.

[whee]

Great point! My first thought was it is grounded though the fuel lines. The I remembered that many, including myself, use a short section of rubber fuel hose at the wing tank so that ground path doesn't exist. I have some copper foil tape I made my antenna out of. Maybe I'll bond the tank to the wing with that.

[marcusofcotton]

Is the tape adhesive reliably conductive?

[yateselden]

I used a hose clamp, clamping the ground wire to a fuel bung

[Archer39J]

This is clearly something that needs to be addressed so thanks for bringing it up! Maybe the kit tanks could include a grounding tab in the future, as it stands now I'll need to figure a way to include a jumper on mine.

[Battson]

I wrapped large copper wire/cable around the welded tank nozzle many times, and secured it tightly by twisting it back on itself and adding a very small amount of solder. I left the insulation on the cable for wear protection, and terminated the other end onto the wing structure with a ring terminal and bolt.

I think we had a thread about this before? As noted, if you used rubber hose in your fuel line then you need to earth the tank (you have rubber grommets in the wing ribs).

My local IA has seen a homebuilt fireball when the fuel tank was not grounded and a spark occurred. The pilot / refueller was terribly burnt.

[svyolo]

How about soldering or silver soldering a wire to the outside of one of the brass tank strainers? I have never tried soldering something directly to aluminum. I will give it a shot.

[Archer39J]

I haven't looked, but I was thinking there might be room to drill and tap a small hole (maybe #8) on the surface of one of the bungs and not interfere with the strainer. Have to see when I get home.

[jaredyates]

Can you get a bare adel clamp around the outside of the bung?

[marcusofcotton]

We should think about high resistance oxidation of materials as well as corrosion issues between different metals. I like to see tight (screwed or clamped) connection of very clean materials that have been coated with an electrical antioxidant compound such as Noalox or No-ox-id.

[Battson]

We should think about high resistance oxidation of materials as well as corrosion issues between different metals. I like to see tight (screwed or clamped) connection of very clean materials that have been coated with an electrical antioxidant compound such as Noalox or No-ox-id.

With the materials we are discussing, galvanic corrosion is only a problem if an electrolyte is present. Inside the wing is pretty dry. No problems so far with copper, aluminium alloy, and steel all close together.

I totally agree with your point though, a welded tab from the factory would be a valuable addition. Perhaps something to share with Mark Goldberg

[interstate al]

Great thread, I was unaware of the need to ground! I think I will tig a tab on each tank before I put my tanks back in the wing.