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Fuel Tank Sender Wiring... When and What?

danielhv

danielhv

Well Known Member
I just finished patching a leaking tank... so in a week or so I'll pressure test, and then hopefully install it onto the wing spar for good... (Is there any other reason to remove it?, should I wait before I go torque sealing everything?) My question is what do I do about fuel sender wiring? I'll obviously need to hook it up and have the wire sitting loose somewhere... do you guys just run it along the forward side of the spar between the tank? Or take it down into the wing conduit somewhere? And what kind of wire do I use?
 
I used 18 gauge wire. Probably over kill.
Ran forward between the wing and fuselage, thus forming a service loop, and through a small rubber grommet just aft of the F-602 sub-bulkhead. Secured to these bulheads and up into the harness bundle behind the panel before reaching the gauges which in my case are on the top RHS of the panel.
Just one option - neat and simple though.
Jim Sharkey
RV6 - getting there!!!!
 
Daniel, the fuel gauge draws practically no current so wire size is not important. I never go smaller than 20 ga. just for ease of working. Where you run the wire is your choice. Just don't run it through the same hole as the fuel line. Electrical and fuel lines each need their own hole.
 
wire

I did capacitive tanks, but the answer is probably the same. The connector is on the inboard side of the tank, next to the fuse. It's not practical to do the fuel gauge line with the rest of the wing wires. I ran the fuel gauge line into the fuse where the main fuel line enters the fuse. This is something you don't have to worry about till you're done with the fuse and doing all the other wiring.
 
Mel said:
Daniel, the fuel gauge draws practically no current so wire size is not important. I never go smaller than 20 ga. just for ease of working. Where you run the wire is your choice. Just don't run it through the same hole as the fuel line. Electrical and fuel lines each need their own hole.
Click to expand...

So I can use any kind of wire? Size is the only determining factor? I guess what Im asking is: can I go to Lowes and use the 20ga or 18ga wire from there? Or does it need to be some special Aviation grade wire?
 
I don't recommend using anything but "aviation wire" in any aircraft. With hardware store wire, you never know what you are getting.
 
danielhv said:
So I can use any kind of wire? Size is the only determining factor? I guess what Im asking is: can I go to Lowes and use the 20ga or 18ga wire from there? Or does it need to be some special Aviation grade wire?
Click to expand...

Dan,
Aviation wire is what you want. Aviation wire has more strands (increases flexibility), the strands are tinned (coated with solder to prevent corrosion) & the Tefzel insulation is extremely abrasion resistant. Industrial wire has PVC insulation, which will break down over the years. It is nowhere near as abrasion resistant as W22759/16 aviation wire. Aviation wire is finding it's way into automobile manufacture, due to it's high quality. See

http://www.militarywire.org/mil-w-22759.htm

http://www.steinair.com/wire.htm

Charlie Kuss
 
Tefzel

danielhv said:
So I can use any kind of wire? Size is the only determining factor? I guess what Im asking is: can I go to Lowes and use the 20ga or 18ga wire from there? Or does it need to be some special Aviation grade wire?
Click to expand...

Oh - I'd use aerospace grade Tefzel everywhere!
MIL-W-22759/16 - get if from Stein or Spruce or Van's
Good insulation and light weight - plus fire and wear proof.
 
danielhv said:
So I can use any kind of wire?
Click to expand...

No.

Size is the only determining factor?
Click to expand...

No.

I guess what Im asking is: can I go to Lowes and use the 20ga or 18ga wire from there?
Click to expand...

No.

Or does it need to be some special Aviation grade wire?
Click to expand...

Yes.

Everyone covered this good in their answers. Just start buying wire now, because from this point forward you'll need a piece here and there for various things. AWG20 will suffice just fine for the fuel senders.

Cheers,
Stein
 
SteinAir said:
No.



No.



No.



Yes.

Everyone covered this good in their answers. Just start buying wire now, because from this point forward you'll need a piece here and there for various things. AWG20 will suffice just fine for the fuel senders.

Cheers,
Stein
Click to expand...

Ok, sorry for the noob questions, the wiring aspect of this is all new to me... So im going to go with the AWG20, white, how much of it should I buy? And what kind of connectors do I need for the float senders?
 
Daniel,

I drilled a third but small hole above the fuel and vent lines. Installed a rubber grommet and ran my sender lines through there. Of course, this was forward of the main spar and bleow level of the wing.
 
danielhv said:
Ok, sorry for the noob questions, the wiring aspect of this is all new to me... So im going to go with the AWG20, white, how much of it should I buy? And what kind of connectors do I need for the float senders?
Click to expand...

I wouldn't bother yet. Wait untill the fuselage is built and the wings are attached - then the electric fun begins :)

Jim Sharkey
 
Hi there I can't ansewer your Question but I have one for you, what do you mean torque sealing ? I am aboute where you are in the building process I am building a 9a . Is the sending unit not facing the fuselage as it is on a 9 and if so it would be inside the fuselage so wiring it would be a snap when the time comes just a guss. Lee
 
Lee Elliott said:
Hi there I can't ansewer your Question but I have one for you, what do you mean torque sealing ? I am aboute where you are in the building process I am building a 9a . Is the sending unit not facing the fuselage as it is on a 9 and if so it would be inside the fuselage so wiring it would be a snap when the time comes just a guss. Lee
Click to expand...

What I was talking about is getting the tank bolts on the Z brackets torqued and then putting torque seal (anti-sabotage laquer) on them... not a big deal, but I just want to attach the tank, torque it, seal it, and be done... It would be an easy process of running the fuel sending wires if the sending unit was on the inboard side of the tank, but both of my tanks have flop tubes, thus the senders are on the rear baffle... so once its on the wing, access to it is impossible without removing the tank first, so Im trying to get wiring information to run some wire out so I can go ahead and attatch the tank. :)
 
An ideal application...

danielhv said:
Anybody know what type of connector I need to use for the fuel sender? (float)
Click to expand...

...of AeroElectric Bob's idea of using a single D-sub pin and socket with a heat shrink sleeve.

Dsub-Pin_Splice_3.jpg


PS - VAF IT Dept. -- what code is used to resize a picture? "[ HTML]<img ....>[/HTML ]" did not seem to work... gives this effect -
HTML: 
<img ....>
 
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danielhv said:
but both of my tanks have flop tubes, thus the senders are on the rear baffle... so once its on the wing, access to it is impossible without removing the tank first, so Im trying to get wiring information to run some wire out so I can go ahead and attatch the tank. :)
Click to expand...


This thread finally makes sense to me now. For most, running the fuel gauge line is a wiring task that can wait till you have the fuse done. I didn't realize that flop+resistive = inaccessible terminal.

So summing up the advice and now adding a few:
- you need wire from stein
- you need terminals like what Gil showed.
- don't buy you're electrical tools, wires, or terminals from autozone. Get this stuff from popular experimental aviation sources.
- You need a quality crimper and stripper.

B&C is a great source and so is SteinAir.
http://www.bandc.biz/ez-catalog/X358218/9
http://www.bandc.biz/cgi-bin/ez-cat...rch=PIDG Style Crimp Tool;limit=product;v=2.0

- Since that terminal can't be inspected(!) once it's on the wing, I'd also put a star washer on that terminal as insurance that it doesn't back out.
- If the wire is routed past z brackets to the inboard tank, you need to make sure there's no possibility of chafing by using grommets or adell clamps (depending on the routing).
 
Does the sending unit (float type) need to be grounded? I've got the gauge wire connected to the center screw on from the sender, not sure of the ground.
 
No extra ground needed.

The sending unit should get it's ground naturally through it's mounting screws.
 
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