Track feeder wire size for N scale

french_guy Jul 15, 2020

  1. french_guy

    french_guy TrainBoard Member

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    Hello all

    I know it must have been discussed plenty of times but I do have a question about track feeders for Kato Unitrack N-scale (and DCC)
    The Kato feeders is apparently made of 24 AWG (blue and white) wires
    I have a bunch of network cable (CAT5E or CAT6) that are also 24 AWG
    Is 24 AWG good enough for track feeders, assuming they remain relatively short?
    I would say if Kato is using 24AWG, it should be fine.....but i prefer to ask anyway
    Otherwise, I could use 22 AGW such as this one for example:
    https://www.amazon.com/Electrical-E...child=1&keywords=22awg&qid=1594826256&sr=8-11

    But again, since I already have some 24 AWG available, I would prefer to use them rather than buying 22 AWG....

    Thanks
     
  2. Sepp K

    Sepp K TrainBoard Member

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    I use 22 ga. solid wire for Unitrack running DCC. I worry about lighter wire not triggering the overcurrent protection on the DCC system.
     
  3. Sumner

    Sumner TrainBoard Member

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    First of all I wish you would of posted yesterday ;). I was looking for red/black in 22 gauge and found some and ordered it but what you found would of been cheaper and better for what I needed :(.

    If you can afford it I'd spend the $15 and be done with it. You are going to have a lot of time and effort into the project so I'd go with the safer bet. 22 is what I chose after doing some research but I also found posts where people said lighter wire worked fine for them,

    Sumner
     
  4. french_guy

    french_guy TrainBoard Member

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    Yes, I can order it
    Does that mean I should not use the Kato feeders with their 24 awg wires? Or I keep them (I have 3, where the red circles are), but any additional feeder I need to install will be with the 22 awg?
    Kato.jpg
     
  5. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    I have used 24 AWG solid conductor feeders, one pair for just about each section of Unitrack on the JACALAR, and have never had an issue with them
     
    Sepp K likes this.
  6. Joe Lovett

    Joe Lovett TrainBoard Member

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    I used 24 gauge telephone wire for track feeders on each section of track with no problems. It has black, red, yellow and green wires. I use red and black for mainline, yellow and black for passing tracks and green and black for yard and spurs. Also the wire harness is connected together at the ends to make a loop so it doubles the size of the wire.

    Joe
     
  7. BigJake

    BigJake TrainBoard Member

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    24 AWG copper is fine for N scale feeders.

    At 1 amp, 3 feet of 24 AWG feeder (two conductor pair) will drop only 150mV (0.15V), or just 1.1% at 14V.

    Multiply that voltage drop by the number of amps you expect to use in a feeder.

    If everything is home-run'ed in 36" or so, you are fine. Otherwise you may want a little bigger gauge bus wire to tie the 36" (or less) feeders into. It all depends on the size of the layouts, and how many locos you want to run at once.

    Here is a useful online calculator for voltage drop for various wire sizes/materials:
    https://www.calculator.net/voltage-drop-calculator.html
     
    Sumner likes this.
  8. french_guy

    french_guy TrainBoard Member

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    I just checked and the wires I have (from a CAT5E cable) are 24 awg stranded, not solid....
     
  9. BigJake

    BigJake TrainBoard Member

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    Stranded vs solid makes no practical difference electrically for this purpose. Stranded is more flexible and less likely to break due to fatigue (repeated bending back and forth).

    Joe's technique of wiring the bus in a loop is a good idea. It also sort of (not completely) evens out the voltage drop around the loop. If you want to have very close to the same voltage drop all around the loop, feed each bus wire in opposite directions (red clockwise, black counter-clockwise), from one point on the loop. This is seldom necessary for DCC, especially if back-emf is used.
     
    Joe Lovett likes this.
  10. BigJake

    BigJake TrainBoard Member

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    There is another way to reduce the number/length of wires to equally feed all loads in parallel, with same voltage at each load, regardless of distance from the source, or how far apart nearest and farthest loads are.

    Take three equal length wires, each long enough to span from source to farthest load, visiting each load.

    The first two wires form a ladder, with loads wired as rungs on the ladder (spacing between loads need not be equal)
    The source is tied between the bottom of ONE side of the ladder and the bottom end of the third wire.
    The top end of the third wire is tied to the top of the OTHER side of the ladder.
     
  11. french_guy

    french_guy TrainBoard Member

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    Since we are talking installing feeders, how to make sure I don't create a short when installing multiple feeders?
    Is the best way to use a car and put a piece of tape on 1 side, and running that car on the whole layout (expect reverse loop) and always solder the same color wire on the side of the tape?
     
    Sumner likes this.
  12. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    That is one way. I put small red and black dots at the base of my Unitrack, then soldered the feeders accordingly. Then had (for non reversing sections) the black dots “to the wall” and the red dots “to room center”. For yours, you can do one color in and the out.
     
  13. french_guy

    french_guy TrainBoard Member

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    Would you have a diagram to explain this?
     
  14. BigJake

    BigJake TrainBoard Member

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    Sorry, I don't have a diagram.

    After I've thought about it, it is really the same circuit as the example above that made a loop of the bus wires, and I suggested powering one bus wire only clockwise, and the other bus wire counter-clockwise on the loop. It really doesn't matter where the loads (feeders) are tied to the bus wires, whether they are closer to one "end" of the loop or the other.
     
  15. BigJake

    BigJake TrainBoard Member

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    how about some crude ascii art:

    +
    --+---+---+---+---+---+---+---+- <--- positive bus wire
    | | | | | | | | <--- loads (feeders)
    --+---+---+---+---+---+---+---++ <--- negative bus wire
    | <--- negative bus wire
    - --------------------------------------+ <--- negative bus wire

    Of course, with DCC, bus wires are neither positive or negative, but you get the idea. They are hooked up to the outputs of the command station or booster.
     
  16. BigJake

    BigJake TrainBoard Member

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    Well, that didn't work...
     
  17. french_guy

    french_guy TrainBoard Member

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    OK, so I started with the 24awg from a CAT5e cable I had laying around...But I thought it was quite tiny
    I was able to reuse (=free) some "old" 22awg cable from the alarm system the previous owner installed but I wasn't using
    Looks much better
    Now, question about the bus (again, N scale in DCC): what is the max cable size the Deek robot arduino motor shield will take?
     
  18. Sumner

    Sumner TrainBoard Member

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    I would go with the size you want. You could always reduce it right at the shield. If it is stranded I like to tin it and if I run into a situation where the wire is too large in diameter to go in whatever I'm putting it in I just cut some of the strands and then tin it. If you are going solid you could just splice a small gauge wire to the end of the larger one and put some shrinkwrap on the splice,

    Sumner
     
  19. Atani

    Atani TrainBoard Member

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    The DeekRobot shield uses a 3.5mm pitch 6pos screw terminal. These will accept up to around 16awg wire without many issues, I use a short segment of 16awg wire (around one foot) as a jumper of sorts to the main track bus which is 12awg (though 14awg would work well in my case)
     
  20. sidney

    sidney TrainBoard Member

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    easy (y):D
     

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