Fuel sender wires location?

[Daddyman58]

Has anyone found that they need additional holes to send the fuel gauge sending wire from the cockpit to the tanks?
If so, where did you put the new hole?
I ran out of "hole" space and was just wondering.

Daddyman

 

[PaulvS]

Has anyone found that they need additional holes to send the fuel gauge sending wire from the cockpit to the tanks?
If so, where did you put the new hole?
I ran out of "hole" space and was just wondering.

Daddyman

I put a small hole and snap bushing in the side of the fuselage just fwd of bulkhead F602 within the wing root area. The sender wire runs up F602 to the sub-panel and the EMS module. This hole location puts the wiring run out of the main cockpit area

 

[Scott Hersha]

My fuel sender sense wire goes through the same hole as the fuel line.

 

[PilotjohnS]

Wow good question. My spar is made up of a machined square section top and bottom ( spar caps ), with a bent aluminum web. Between the web and the bottom spar cab, there is a little groove. I ran my fuel sense wire in that groove protected by an additional piece of Teflon tubing, and secured with RTV. This allowed it to come into the fuselage without any additional holes, and without having to run it near a fuel line. (I don't like wires near fuel lines, it's just me OCD)

 

[JonJay]

I put a small hole and snap bushing in the side of the fuselage just fwd of bulkhead F602 within the wing root area. The sender wire runs up F602 to the sub-panel and the EMS module. This hole location puts the wiring run out of the main cockpit area

Ditto

 

[Mel]

My fuel sender sense wire goes through the same hole as the fuel line.

No electrical wires should ever share the same hole as fuel lines.

 

[RV6_flyer]

Three decades ago when I was building, I ran the fuel sender wires (signal and ground) into the bundle that also has the strobe power supply, nav light, and landing light wires. There are two connectors each side between the wing and the fuselage. One connector is fuel sender and the other is all the other wires. I made one hole in the fuselage forward of the main spar for the wires to pass through. All my wing wires run forward of the main spar.

 

[Daddyman58]

Ditto

All,
Thanks for your replies.
I was thinking the best method would be a small bushing in the location mentioned.
Your collective response confirmed my idea and helped bolster my weakened self-confidence.
Daddyman

 

[Daddyman58]

No electrical wires should ever share the same hole as fuel lines.

Tempting, but the little voice in my head said "no-no".
Dadddyman

 

[Daddyman58]

Three decades ago when I was building, I ran the fuel sender wires (signal and ground) into the bundle that also has the strobe power supply, nav light, and landing light wires. There are two connectors each side between the wing and the fuselage. One connector is fuel sender and the other is all the other wires. I made one hole in the fuselage forward of the main spar for the wires to pass through. All my wing wires run forward of the main spar.

Gary,
OMG.
Were that to be true with my -6A. I have a shit-ton of wires running aft.
Editor: Shit-ton is not a cuss word, but in fact, an actual British term.

Daddyman

 

[Scott Hersha]

No electrical wires should ever share the same hole as fuel lines.

My sense wire (tiny milliamp current) and the aluminum fuel line is electrically separated with boots and heat shrink that maintains separation. Just passing through the same hole in the fuselage. If I drilled a separate hole for the wire - in the aluminum skin pretty close to the fuel line hole - it would be electrically the same. Makes no sense. I understand that certified airplanes wouldn’t do it this way, but I didn’t build a certified airplane. I appreciate Mel’s post and understand the reason for it, but I think there are ways to manage this level of protection in a more builder friendly way.

 

[n4322b]

No electrical wires should ever share the same hole as fuel lines.

somewhat difficult in some locations such as the fuel pump. Better "avoid when possible" rather than "never"
On my 7 I ran out of space for wires in the standard opening through the fuselage out to the wing. Support sent another drawing trying to identify (with a red triangle) where an additional opening was allowed. Maybe they have same for the 6.

 

[Mel]

somewhat difficult in some locations such as the fuel pump. Better "avoid when possible" rather than "never"
On my 7 I ran out of space for wires in the standard opening through the fuselage out to the wing. Support sent another drawing trying to identify (with a red triangle) where an additional opening was allowed. Maybe they have same for the 6.

You guys can do whatever you want. I'm just telling you the rules in AC 43.13 (Acceptable Methods, Techniques, and Practices - Aircraft Inspection and Repair).

 

[Desert Rat]

I didn't want to run this wire through the fuel line grommet for the reasons that Mel stated, especially since I have a capacitance system that has an actual power wire, not just a wire measuring resistance.

I used the routing somebody else already mentioned; I installed caterpillar grommet on the skin edge forward of the spar cutout, sleeved the wire with chafe protection, then routed it out in the gap between the skin and the spar web. It's held in place with a dab of RTV, a couple of wire tie mounts glued to the skin with E6000, and a couple of adel clamps butterflyed off the fuel vent line.

 

[Desert Rat]

"...All my wing wires run forward of the main spar..."

That won't work in the later airplanes. Due to the tank mounting Z brackets there's no space between the tank and the spar to route stuff outboard. You have a situation where all the wing wiring and plumbing has to come out aft of the spar except whatever goes to your fuel senders, which has to somehow get in front of it. On the RV7 and presumably the 8 & 9, there are no instructions or suggestions from Vans whatsoever on how to do this, so thats why the question comes up.

 

[mburch]

Here's how I did it - tiny grommet in a hole that goes through the fuselage side, and through the bracket where the cover plate attaches in front of the spar.