Running conduit questions

[RickWoodall]

If anyone had a good link or comments on conduit it would be appreciated. I know very little about the electrical part, and I have not yet bought the aeroconnection book. I want to get conduit run so baggage floor can go in, and just wondered if anyone had a rough diagram or comments on conduit. if I run one conduit from firewall to back and one out to each wing is that adequate? Should I run a couple to the back and two out to each wing? Might be a dumb question but I just need to know, i suppose there is no harm in having a couple extra runs in the floor. Strobes, landing, taxi, nav light will all be going in, as well as gps, radios etc. Just not sure if wires can all go in one conduit or if they should be spread out, lighting in one conduit, others in seperate. Stuck in rivet mode...figuring out the wiring is a fall job.

Any links appreciated

[Mike S]

Well, lots of questions here-------------

The desired final configuration of your plane will dictate how many conduits, and size and location.

Day VFR, and steam gauges VS full IFR, all glass, night etc.

Wiring for some things is not compatible with wiring for others-------AHRS/magnetometer wiring in same conduit as high side strobe lines for example. Transponder coax with any other wiring is also problematic.

I an in the middle of exactly what you are going through-----only I am working on a project some one else started. After drilling out the floor boards, I ran a total of 4 conduits under the rear seat area on the left side, and there is one on the right. -10, in case you were wondering about the "rear" and left/right thing.

I used flexible PVC conduit from Home Depot, 3/4" and PVC fittings to terminate the front end at a bulkhead. The stuff is meant for electrical use, commonly called "Smurf" tube around here by local electricians.

You need to sit down and figure out what needs to be run where, and make a plan. Things to consider are battery location, strobe---single power pack or three, ELT location, if glass cockpit, where are you going to put sensors for heading/compass, audio wiring, ETC ETC.

Time spent planning is way more efficient than time spent re-working something not well thought out.

Whatever you end up with, it is probably wise to put in extra just in case---------sure beats drilling out all those pop rivets.

Good luck,

Mike

[Kyle Boatright]

Originally Posted by Mike S

Whatever you end up with, it is probably wise to put in extra just in case---------sure beats drilling out all those pop rivets.

Good luck,

Mike

Mike is exactly right. Install extra conduit, or at least oversize what you install.

I've postponed buying and installing a single axis (roll) autopilot for at least 2 years because I didn't install extra conduit in the wings of my airplane when I built it. Getting the wires out to a servo mounted in the wingtip is a big problem for me at this point.

[airguy]

After installing your (oversize) conduit, leave a pullstring in place in the conduit tied off to something on both ends, so you can attach a wire to it at a later date and pull it through easily.

[Mike S]

Originally Posted by Kyle Boatright

Mike is exactly right.

Thanks Kyle.

I'll get the check in the mail.

Mike

[Sam Buchanan]

KB lamented:

I've postponed buying and installing a single axis (roll) autopilot for at least 2 years because I didn't install extra conduit in the wings of my airplane when I built it. Getting the wires out to a servo mounted in the wingtip is a big problem for me at this point.

Kyle, the utility of the wing leveler is worth the effort to run the servo wires. How 'bout running a thinwall PVC pipe from the wing root to the inspection hatch, then another one from the inspection hatch to the wingtip. The pipe can be inserted via the wingtip through the lightening holes and secured to the ribs with a combination of adel clamps at the ends of the pipes. I believe the only interference problems will be around the bellcrank; that is why you want two pieces of pipe so you can work the cable about the bellcrank area.

I did something similar to this when I added the LRI indicator and its associated plumbing.

[thallock]

You don't need to worry about leaving a string inside the conduit so you can pull wires later. All you need to do later is to tie a string around a piece of cloth, cotton, tissue, whatever, and suck it through with a vacuum. Works great, and no need to worry about making sure the original string is tied-off, protected, etc.

If you already left a string in place, no problem, that will, obviously, work, also.

BTW, how did you get the string in there in the first place?

Tracy.

[brian]

I think most everyone uses rigid or flexible PVC for their conduit. The thinwall stuff made for lawn sprinklers is probably the best bet. However, I think that any conduit in the cockpit/interior should be metal, not PVC, for the same reason we should be using Tefzel or Teflon wiring insulation, not PVC. When I did mine, I ordered the thinnest wall aluminum 6061 3/4" tubing that ACS had, and I used that. See here for example:

http://meyette.us/BaggageFloorAccessPanels.htm

The aluminum costs more, but I don't think PVC conduit in the cockpit is a good idea, and steel conduit is way too heavy

brian

[brian]

oh - and I clicked "send" too quickly - I certainly agree with the others' postings - if in doubt, add the conduit, if in doubt as to size, go bigger.
brian

[RVbySDI]

Originally Posted by brian

The aluminum costs more, but I don't think PVC conduit in the cockpit is a good idea, and steel conduit is way too heavy

You have my curiosity up on this statement. Why don't you think using PVC conduit in the cockpit is a good idea?