I'm consulting with a company that buys and sells used aircraft parts. The owner gave me an entire spool of twisted, 3-conductor, 15 gauge aircraft wire that should work very well with DCS. It's actually 1.4mm, but that equates to 15 gauge. My question is this: Can I use the 3rd conductor for anything? In other words, I have an extra wire that's going to be going all over the place and can it be used to carry power for, let's say, accessories or switch power? Will having another current flow in the twisted array interfere with the DCS signal? This is saving me $$$ and it was a very generous gift. The spool came with a surplus load of wire that came from Airbus.
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The third wire would probably be good for a switched siding or stub track. Otherwise just consider it a factory extra.
My first thought was this: since you have DCS I'm assuming you have a TIU. If you're using star wiring that would imply that you are using terminal blocks central to your layout, right?
Well, by example only, you could do this: take 2 of the wires and hook one to VAR1 + and the other to VAR2 -. Take the 3rd wire and hook to FIXED1 +.
Then take another wire and use on wire for FIXED1 -. Use the other 2 on FIXED2 + and -.
Then take a 3rd wire and use 2 of the wires on VAR2 + and -. That only wastes one wire that way.
Of course I'm making a small assumption that your terminal blocks are near each other.
- walt
I expect that you could use the 3rd wire to supply hot to a separate block with no problems.
If by any chance you're using any accessories that ground through the track (crossing signals come to mind), you'll be needing runs of just single conductor from a transformer to power these accessories. If you have your three-conductor running from the transformer/TIU area to various track feeds, you might be able to grab a nearby unused-third-conductor from a track feed, to power the crossing signals in that area?
Also, Walt's post got me thinking: two runs of your three-conductor equals three runs of two conductor, to feed three drops with two of your gift wire - again, if the drops are near each other.
Just label everything really well and try to stick to a consistent use of the color coding. Three years from now, the unconventional uses of that third conductor will not be obvious to anybody, maybe including yourself!
It seems to me that the only problem would be with induced noise. You could use it to power another block or for power to something like a switch that doesn't use power continously but only when activated.
Al
Thanks for the responses, but now that I have the wire in my hands I find that the whole thing may be moot. The wire is actually somewhere between 20 and 22 gauge, way too small to carry the DCS power signal. It's terrific wire with a teflon insulation, copper foil, and full shielding. It's great digital stuff probably equivalent to Cat 5, but it's too small.
What do you think about doubling up the conductors? I have a couple thousand feet of the stuff so running double leads wouldn't cost me anything other than time. I could combine two conductors together and get a much higher current carrying capacity. Would this work, or should I use this wire for turnouts, signals, lighting and accessories and bite the bullet and buy the correctly sized wire.
Here's the spool and the wire that I stripped and put on some ferrules. The red ferrule was too big, the white fit correctly.
Pardon the focus...This was an iPhone shot.
Attachments
I seem to remember from high school, in the last century, that a reduction of 3 gauge numbers is double capacity, so you'd need all 3 conductors to carry power adequately.
I would divide the layout into block sections of the outside insulated rails. Use one wire for center rail feed drops. Use the other two for commons to the outer rails,one for the unblocked common and one for the outside insulated rail. The insulated rail blocked wire can go to a barrier strip,from there it can be connected to back to common or used for a relay to activate track accessories such as block signals or crossing gates. So even when all the track is laid,such accessories can be added later easily at any time to activate at any section of the layout without disturbing the track..
I do it this way on my conventional layout using 16 gauge outdoor extension cords which have 3 conductors with the ground.
Dale H
As Dale suggest you can use the wire to control relays that switch the power to the track. In large layouts this can actually improve DCS operation since it keeps the feed wire the same length between the hot and the neutral. On the other hand you could double it up and use it for long runs to switches. I'm thinking that two 22 doubled together should give you about the equivlant of a 18. For short runs to switches, say 8 to 10 ft., you could use it as is. In any case I certainly wouldn't throw it out.
Al