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i want to run four bus wires (one for each loop) and wanted the bus wires to be different colors so that i could identify them -- i started out with an 18 gauge red and black.  For the second bus, i wanted to use another two color wire, so not thinking i used a blue and black 16 gauge wire.   Now i just purchased a third roll orange and silver thas12 gauge.  Is using three different gauge wires going to cause me a problem?  If so what is the best gauge for bus wires that run 50 feet +/-?  and any idea where i can get the paired wire in different colors?  thanks!

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You'll be fine at 50'.  You'll get arguments for and against for 16 gauge vs 18 gauge but either will work on that size layout.  There's nothing wrong with 12 gauge but that's overkill.

If you are wiring for DCS you should wire using a Star pattern vs a bus wire.

I recently got a whole bunch off of Amazon - Southwire sells wire in multiple colors:

https://www.amazon.com/gp/prod...00?ie=UTF8&psc=1

-Greg

Last edited by Greg Houser

Let me add my voice to those that are telling you that 18 gauge wire is too small for the current loads it will be carrying. The absolute minimum track power feeder size should be 16 gauge, and even a size larger (14 gauge) if you can work with it.

A bit of first-hand experience:
I was shooting video on a large layout for one of the OGR Great Layout Adventures videos. The layout owner had double headed a couple of steam locomotives for this particular shot. We shot the scene once, but I didn't like what I had done with the camera, so we backed the train into position for take two. I started rolling video; the owner started the train moving; and suddenly smoke started coming up from the bottom of the layout...a LOT of smoke!  We instantly shut everything down to investigate. It turned out that the track feeder for this section of the track was 18 gauge wire. The insulation on this wire was burned to a crisp over a length of almost 15 feet! However, the wire was still carrying current and the train was still running fine when this happened. The wire had to light up like a light bulb filament to get this hot so fast. If this wire had been positioned any closer to surrounding layout materials, it would have started a fire.

If there was ever place NOT to skimp when building a layout, it is on wire size. Use 14 or 16 gauge for track feeders, but never 18 gauge. It's just too small.

Last edited by Rich Melvin

Thanks for all the advice, i have a layout that is roughly 16' x 16' but in the shape of an "L" and the bus wires run the entire distance in four loops

the outside (main) bus is 18 gauge (that was the first one i did) but then the inner loops are 16 and now 12 gauge -- the track loops have breaks in them

so it sounds like i should have used 12 or 16 gauge wire all around, but since i have already installed the 18 gauge, with feeders around the track, and the wire does not get hot, i think that i am ok?  at most i would run two engines lashed up on a particular loop at a time

thanks for all your advice

steve

I've been reading this and want to say thank you, and this is relevant to my new layout I am preparing to build.   Since the thread is already asking -I'd like to expand on the topic as I'm sure the answers will benefit the OP.  

I have 2 loops I am preparing to build, basically its 60 feet for the circle for the bus wire for each loop.   I'm going to go with 14ga as suggested (for each loop).  

1.   Do the feeders going up to the track need to be 14 also, or can these drop down to 16,18, etc?   I'm guessing they will only be 8-10" long each, right?

2.   Can this be solid copper, or does it need to be stranded?   Does it matter and why?  It seems I heard somebody say it does...

3.   The wires running from transformers to switches (separate from track power) I thought were lower voltage and are daisy chained, right?   I have around 12-14 switches planned.   What is the gauge to use there?   I"m was thinking since switches are low voltage/amps I thought 18 or 20?  

Thoughts from the darn smart EE people!   Build it once, build it right.

Thanks!

You can use smaller feeders, I used #18 for mine and #14 for the long runs.  Solid or stranded will make no difference.  I find stranded a lot easier to deal with when wiring.  Heed the warning about pure copper vs CCA (Copper Clad Aluminum).  CCA is junk, don't fall for that!

The size of the switch wiring will depend on the switch machines in use.  For Fastrack, #24 is sufficient, for Lionel tubular track switches, I'd probably recommend #18, those draw a lot more current when they switch.

Here is what Lionel says about wire:

"Wire comes in many sizes in solid and stranded varieties. Stranded wire is really a bundle of smaller diameter wires wound together. Wire size is indicated by a number – the larger the number, the smaller the wire. Most house wiring in No. 12, solid wire. For your layout, we recommend a No. 16 stranded bus wire with No. 18 feeders. The feeders do not have to be as large because they are not as long and it is easier to attach the smaller wire to the tracks. Stranded wire offers better electrical flow (electricity flows around a wire, not through it) and it is easier to bend. We recommend adding feeders at least every 10 to 20 feet around the track."

FWIW, my personal preferences are:

14 gauge mains

16-18 gauge feeders, depending on what I have hanging around

Stranded pure copper wire throughout

Feeder every 4-8 track sections, depending on the length of the track in each section

Star wiring using MTH 12-24 port terminal blocks if wiring for DCS or potential DCS usage

2 port terminal blocks for connecting mains to feeders if using star wiring - suitcase or Wago style connectors for bus wiring

Wago connectors are infinitely better than suitcase connectors. Worth the extra costs hands down!

Here is an assortment: https://www.amazon.com/Wago-22...rtment/dp/B01GVTVY12

Just be sure to get real Wago ones and not the off brand knock-off lever nuts as the knockoffs do not meet UL or other safety standards and are of inconsistent quality. That is not to say that one may not find that certain knockoffs are just fine for this low voltage purpose, but I can't justify taking the chance after getting burned.

Last edited by bmoran4

Great information here and answers some of the issues I have experienced. However one question that has me stumped, and basic one so I apologize, is the buss wire. Where does the buss wire start and terminate? does it start directly from the transformer, i.e Z400, one hot and one ground wire? Or wire from the transformer to a block, i.e MTH 1014,? I know it goes around the layout (mine is 12 X8)  with drops from the tracks every few feet. But where do the main buss wire terminate? At the terminal block? Or at the transformer?  I cannot locate this information? At least I am not able to locate it.



Thank you all

@Steven posted:

However one question that has me stumped, and basic one so I apologize, is the buss wire. Where does the buss wire start and terminate? does it start directly from the transformer, i.e Z400, one hot and one ground wire? Or wire from the transformer to a block, i.e MTH 1014,? I know it goes around the layout (mine is 12 X8)  with drops from the tracks every few feet. But where do the main buss wire terminate? At the terminal block? Or at the transformer?  I cannot locate this information? At least I am not able to locate it.

Steve, keep in mind that any bus has to be adjusted based on the type of running, conventional, TMCC/Legacy, DCS, all of the above, etc.

For conventional, you'll typically have power drops to allow you to control individual loops and/or tracks from a transformer handle.  For command running, you'll likely have power districts to divide the load across more than one transformer output.

For TMCC/Legacy (and not DCS), a bus configuration is suitable, the drop runs directly from the transformer and around under all the track that will be controlled by that transformer drop.  My advice is to run both center and outside rails for any bus connection, don't try to use one common with multiple hots.

For DCS (works also for TMCC/Legacy), you will want a star wiring scheme for best results.  That means a run from the transformer typically goes to a terminal block somewhat centrally located for the track(s) being powered from that run.  Then individual runs go from that terminal block directly to the individual track drops.

gunrunnerjohn



Thank you for the response. I am running conventional (my DCS attempt was a failure but my fault).

Anyway, if I understand what you wrote, the buss wire starts at the transformer and runs around the layout with power drops, ec. But what I am still missing, and sorry for this, is where the do the bus wires end? Back at the transformer? In my mind there has to be a loop connecting somewhere. And yes, electrically challenged as the questions appear.

TY !!!!!

NO, the bus wires end at where ever you run out of track, that can be anywhere.  The individual bus wires don't have to be a "loop", because the circuit in question is between the center rail and the outside rails.  Any current in the circuit flows through the locomotive, lighted cars, etc. that are on the tracks.

If that weren't the case, you couldn't connect a piece of track on a bench to a transformer and have something power up and run on that track.

Rich,

Wow, that is a scary burned wire story.

I used 18 gauge power feed wire on my layout, with a set of power wires on every 5 feet of track.   I did not run a bus wire.  Both the hot and common wires running to each piece of track are separate runs of wire, coming off a distribution block which is one foot from the transformer.  The wires from the transformer to the distribution block are 12 gauge.

I guess the longest run of the twin wires to a track section are about 9 feet.

I have run two large engines, and lighted cabooses, on my layout every day for 14 months.  I've never had any of the wires get hot or burn.

So, maybe the problem with 18 gauge wire is on really long runs?  Or, using it as a bus line for multiple power hook-ups?

Thanks,

Mannyrock55

I'm not going to get worked up over them not having a UL rating, remember that the Lionel ZW-L doesn't have a UL rating.   How about all the post-war transformers in constant use on layouts all over the country, they'd never pass a UL ratings check?  Is your track UL rated?



This is the connector on Amazon that I used, note the PCT-213 part #.

I happened across the actual specifications on another site for the same PCT-213 Connector.

I think these are more than sufficient for the task.

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@Steven posted:

gunrunnerjohn



Thank you for the response. I am running conventional (my DCS attempt was a failure but my fault).

Anyway, if I understand what you wrote, the buss wire starts at the transformer and runs around the layout with power drops, ec. But what I am still missing, and sorry for this, is where the do the bus wires end? Back at the transformer? In my mind there has to be a loop connecting somewhere. And yes, electrically challenged as the questions appear.

TY !!!!!

Household circuits are basically a buss, in the sense that the hot,neutral and ground wire terminate at the last device on it ( meaning outlet, light fixture,etc.) Household wiring starts at the breaker box and does not loop back to the origination point.

As long as we are talking wire... I'm seeing "single conductor copper stranded wire" on amazon.   I thought stranded was multiple little wires and that is what it shows in the pic, but what is single conductor?   I just want to buy the right wire and I'm looking online right now and don't want to buy junk.   Do I need THHN?  Should it say that?

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