Model Railroading > Bus wire and feeder question

Hello all;
     Building an overhead layout in my home.  Run is 80 feet long. Might need to have breaks in the run for different sections as this will hang from the ceiling. Probably use Molex connectors for that.  Question: Should I go with 12 or 14 solid for the bus? Thinking 18 gauge stranded for feeders. Also, suitcase or solder for feeders.?
Want to make sure I am on the right track for this ( pardon the pun)  and get it right the first time as I am getting to old to stand on ladders for long periods.
Any and all feedback is appreciated!  

12 will have slightly lower resistance but 14 is good for up to 15 amps. Suitcase connectors are fast but are only mechanical. If you want reliability, I'd go with soldering.

Ken
 

14 gauge is plenty you will only be putting 5 amps or less thru it mostly in the order of 1-2 depending on the gauge. I have 14 gauge on mine which is more than enough and 20 gauge feeders. All joints are soldered will never use suit case connectors too much chance of a bad joint. Know that many do use them but solder is the right way to go.  A side note my layout I have MMI engines in ON30 scale the main line before feeders was over 100 ft total and fed from ONE spot only had up to three engines running at the same time.  I had no problems with controling them or speed problems I have a 5 amp NCE system and soundtraxx decoders.   Too often people think that you need heavy wiring but not true and think of the feeders as just what they are and are not handling much due to all rail joint being soldered. They being small are easier to deal with and by the way use solid wire for both feeders and buss. These engines use the same O scale motor as there ON3 ones do. Boyd in Chiloquin home of Train Mountain.

For a layout 80 feet long, 12 or 14 is fine. 

18 is fine for the feeders. I'm guessing you're building in O or G. I use 22 for HO scale.

DEFINITELY solder your wiring. Some people swear by the suitcase connectors. I swear AT them. 

Every time I've built a module with suitcase connectors, at some point in the future something gets dinged and I lose power to a piece of rail. I don't know why so many of the Kalmbach writers like them. They must own shares in 3M.

Soldering is also "almost free" per connection, and if done well can be almost invisible. Suitcase connectors can get expensive and very visible.

-Jason

12 or 14, you should be fine.   80 ft bus = 160ft round trip electrically.   If you assume that some load way out at the end is consuming all 5A from the booster, you're looking at the following voltage drops:
12AWG is 1.59 milliohms per foot, 5 * 160 * 0.00159 = 1.2V of drop in the bus.
14AWG is 2.52 milliohms per foot, 5 * 160 * 0.00252 = 2V of drop in the bus.

That's your absolute worst case scenario, and not terribly realistic.  In typical scenarios I'd guess maybe 1-2 amps way out at the end, maybe ~0.5 of drop.  That's trivial and you'll never notice.

Personally I use 14AWG stranded and 26AWG feeders (all <8 inches long), all soldered or connected by terminal blocks.  Like Jason, I swear at suitcase connectors, not by them. :)  I'd suggest buying yourself a Klein 11063W "Katapult" wire stripper (or similar).  Makes it really, really easy to open up the insulation in the middle of a bus wire to solder a feeder to it.  Basically you squeeze the handle and a set of blades cuts the insulation while a set of jaws pulls it back, exposing the wire.  Fantastic tool.

The one thing I will say is with a bus that long, consider gently twisting the bus wires along the run and putting a snubber circuit (just a resistor and a capacitor - there's lots of information online, just search for "dcc snubber circuit") at the end.  Long bus wires can create interesting inductive effects that can cause nasty voltage spikes.  At best, those spikes can confuse decoders, and at worst I've seen them kill decoders (on some truly horrendous layout wiring, tie-wrapped to steel benchwork to make it so much worse).

Nathan

It's a really good idea to solder Layout wires and use appropriate bus terminal strips, on the other side a lot of people are just not into soldering and buying additional tools when all they want to do is run some trains. Many of us have had to chase down a cold solder joint. Perhaps this is what 'suitcase' connectors were invented for. There's a number of interesting discussions about suitcase connectors in the TO archives btw.

There are a number of well known layouts using them without problems, they also tend to have other high work standards that may overcome common problems. There's also a lot of simply cheap suitcase style connectors out there and a lot of wrong wire sizes being used with them. If a person is going that route buying 3M connectors makes a big difference. Also use the recommendations from 3M on wire sizes, mostly the difference between the main and the branch. I'm tending to use solid wire in them, but I do appreciate the idea of stranded wire. Many people have trouble finding a good source of wire, it is worth the extra effort to track down a good source.

Just in case, I solder just fine, at one time it was a requirement for my job. Plenty of classes, plenty of layout wiring with solder. I already have a couple of decent quality soldering stations, Weller WES51 for example, that I tend to use on track feeders instead of messing with under the layout stuff. Somewhere there is a perfect world with perfect Layout wiring. Hope we're all heading in that direction.

rapidotrains Wrote:
-------------------------------------------------------
> For a layout 80 feet long, 12 or 14 is fine. 
>
> 18 is fine for the feeders. I'm guessing you're
> building in O or G. I use 22 for HO scale.
>
> DEFINITELY solder your wiring. Some people swear
> by the suitcase connectors. I swear AT them. 
>
> Every time I've built a module with suitcase
> connectors, at some point in the future something
> gets dinged and I lose power to a piece of rail. I
> don't know why so many of the Kalmbach writers
> like them. They must own shares in 3M.
>
> Soldering is also "almost free" per connection,
> and if done well can be almost invisible. Suitcase
> connectors can get expensive and very visible.
>
> -Jason

The telecommunications industry has used "Insulation Displacement" connectors, aka Scotchlocks, for many years with few problems.
It's all in how you install them. Use the proper connector for the gage of wire you're using with the proper tool, not a pair of pliers, and you will get a good, reliable connection.
I've seen many more bad soldered connections then I have scotchlock connections. Soldering is a skill bordering on an art form. Takes practice to learn to do it right.

The "secret" to using suitcase and other "insulation displacement" connectors is to use the correct connector for the gage of wire.

I have several terminal blocks spaced around the layout and "home run" all feeders to it. Ring terminals on all wire terminations at the blocks, soldered to rail on other end. It might be a few extra feet of wire, but works great. 12awg is good for 20A, something you will never get close to. 18 awg is perfect for feeders.

I wholeheartedly agree with Jason and have avoided suitcase connectors like the plague.   I solder everything.  


rapidotrains Wrote:
-------------------------------------------------------
> For a layout 80 feet long, 12 or 14 is fine. 
>
> 18 is fine for the feeders. I'm guessing you're
> building in O or G. I use 22 for HO scale.
>
> DEFINITELY solder your wiring. Some people swear
> by the suitcase connectors. I swear AT them. 
>
> Every time I've built a module with suitcase
> connectors, at some point in the future something
> gets dinged and I lose power to a piece of rail. I
> don't know why so many of the Kalmbach writers
> like them. They must own shares in 3M.
>
> Soldering is also "almost free" per connection,
> and if done well can be almost invisible. Suitcase
> connectors can get expensive and very visible.
>
> -Jason

Great info. Thanks again everyone!

I use T connectors where I would get covered in Solder, and solder where I can without it dripping on me... Hate hot solder.. and a good pair of pliers is the key for a good suitcase connector

To forth district, the auto and truck industry does not use suitcase connectors, gyppo shops do and then when they fail problems start.  Have been in the industry for fifty plus years and have repaired many suitcase connector jobs.  They are subject to corrosion as most are not the protected kind.  And on another subject you can easily run the two buss wires abotu two inches apart like I did and dont have to twist anything. As for stranded wire its not needed for our low amp use solid works great and is easier to work with. 14 gauge is plenty for every thing up to G scale.  And buss wire run lenght of 100ft is with little or no voltage drop due to low amp usage so to all the long time DCC guys many things are easy but your types make it hard for new people to understand things. A buss wire jumper to track every ten feet is plenty. Know so been there proved that.

I am using 3M suitcase connectors for Free-mo wiring. After lots of research I have come to the conclusion the biggest problem with wiring is the connectors is with multiple size wire connections. I buy the uniform size 12ga and 12ga connectors. That means once you get the metal connector flat across both wires the pressures and stress should be equal. You need to watch the metal connector is pushed exactly perpendicular to both wires. The main 12ga wire goes through the long run of the suitcase while the short run gets a 12ga pigtail with the open end stripped bare so smaller 18ga or 22ga wire can be soldered and shrink wrapped there.

I have only been experimenting with this for about a year no so whether this is a long term solution remains to be seen. The nice thing about modules is you can invert them during construction and risk dropping solder into your face.

Several years ago I bought a special  3M tool to clamp down the connectors and it broke. I soon found a plyer (much less expensive) that folks here recommended and it works fine. I should have returned the tool but didn't get around to it.

Victor A. Baird
http://www.erstwhilepublications.com



Edited 1 time(s). Last edit at 10/14/18 07:51 by wabash2800.