Wire run behind fuel tank: safe?

[Stewie]

Hi all-
I am running VOR coax and LED strobe/nav wiring from my RV4 wingtip through bushings on the forward side of the spar. These join up with the safeair aoa/pitot plastic tubing near the bellcrank, and I plan to run this as a bundle in the space between the fuel tank and spar into the fuse. There are no exposed wires or quick disconnects in the area behind the tank. I am curious if others have done this and if it would be considered safe/unsafe to run wiring behind the tank like this. I'd like to keep things simple and light, so I'd prefer not to use conduit if I can safely do so.

On a related note, I have SW fuel senders in the wings, so obviously in that case at least there is a wire in direct proximity to the fuel tank.

(I did search the forums on this but was not able to find any info. Not sure how other RVs are built so the moderator can feel free to move this to the RV4 forum if that would be more appropriate.)

Thanks,
Eric

[Av8torTom]

Not familiar with the 4 but are there Z brackets holding the tank to the front of the spar? If so, how will you get through those? Any reason why you can't run your wires behind the spar?

[rv7charlie]

No Z brackets in a -4.

I wouldn't worry about the VOR coax at all. If your strobe & nav are both LED (no actual high voltage pulses to fire a strobe tube) I probably wouldn't worry too much about those, either. That assumes that you can be confident that they won't ever move enough to wear through the insulation (operating with the pessimistic assumption that the tanks *will* leak someday).

Charlie

[RV6_flyer]

Originally Posted by Stewie

Hi all-
I am running VOR coax and LED strobe/nav wiring from my RV4 wingtip through bushings on the forward side of the spar. These join up with the safeair aoa/pitot plastic tubing near the bellcrank, and I plan to run this as a bundle in the space between the fuel tank and spar into the fuse. There are no exposed wires or quick disconnects in the area behind the tank. I am curious if others have done this and if it would be considered safe/unsafe to run wiring behind the tank like this. I'd like to keep things simple and light, so I'd prefer not to use conduit if I can safely do so.

On a related note, I have SW fuel senders in the wings, so obviously in that case at least there is a wire in direct proximity to the fuel tank.

(I did search the forums on this but was not able to find any info. Not sure how other RVs are built so the moderator can feel free to move this to the RV4 forum if that would be more appropriate.)

Thanks,
Eric

Eric:

The -6 and -4 both have the same mounting. Neither use the "Z" brackets that are on the later RVs.

It is safe to run your wires between the main wing spar and the tank on the -4 or -6(A).

I have been flying my -6 almost 15-years and over 2,600 flight hours just like you are talking about. Nav on one side and the power wire to my strobe power supply on the other. (other side meaning top and bottom so that they are away from each other) Yes I have two power supplies for the wing strobes. No strobe noise in the electrical system with the power supply mounted on the front side of the spare out near the wing tip.

[Sid Lambert]

Just tie them up nice so the screws won't rub on the wire but you should be good. You can get some fuel sitting on top of the lower spar flange if you overfill or have a gasket leak so try to keep the wire higher than lower.

[Mel]

Literally thousands of RVs have been flying for decades wired just like this.
Build on!

[rv9av8tr]

Originally Posted by rv7charlie

No Z brackets in a -4.

I wouldn't worry about the VOR coax at all. If your strobe & nav are both LED (no actual high voltage pulses to fire a strobe tube) I probably wouldn't worry too much about those, either. That assumes that you can be confident that they won't ever move enough to wear through the insulation (operating with the pessimistic assumption that the tanks *will* leak someday).

Charlie

Don't let voltage be your guide.... You can weld with 6 volts until the wire melts!!

[Stewie]

HI all-
Thanks for your input. Glad to hear this is an accepted and safe method for running wires. VAF is a fantastic resource.
Eric

[rv7charlie]

Originally Posted by rv9av8tr

Don't let voltage be your guide.... You can weld with 6 volts until the wire melts!!

You want to maybe give that a little thought (in context), & see if you stick by the statement?

Charlie