I'm in the process of routing the major wires for my new layout.  I have following 4 basic layout busses that need to be routed:

• Main DCC buss: 14 gauge wire
• NCE Throttle buss: Small gauge 4P4C wire
• NCE Control buss: Small gauge 4P4C wire
• MERG Cbus main buss: 12 VDC Cat 5 cable with separate 0 volt ground

What I'd like to do is group the low voltage busses, i.e. the throttle buss, control buss and the Cbus all together on the front edge of the layout and put the high power DCC mains on the back of the layout.  The idea is to keep the resonating power of the DCC away from the electronic signals of the other busses.  Does anyone have any experience doing this or have any other suggestions?

I appreciate the help.  


Regards,

Tom Bailey

Hi Tom,

There are many combinations of signal buses and power buses.  There is no way for me to test all configurations.

I don't think you need to go so far as put your DCC bus all the way at the back of your benchwork.  On my current layout, all my wiring except for 120V AC wiring is near the front of my benchwork.  I am running my signal buses like NCE Control Bus and Digitrax Loconet over my joists.  The DCC track buses are running through hangers hanging from the joists.  So the signal buses are separated from the track buses by about 5".

My layout is still under construction and as such, I have not had more than one test loco running.  If I find them too close, I can move my signal buses farther way.

As you might imagine, I have a lot of connections to the track bus.  So for ease of wiring and not having to crawl under the benchwork, I prefer to keep the track bus near the front  of benchwork.

Allan Gartner
Wiring for DCC

Your wiring scheme makes great sense. I wish I had thought through
mine the same way when I began building my layout over a dozen years
ago. But back then, I didn't have a clue about: (a) signal bus wiring
or (b) using SMAILs instead of Tortoises. Even with SMAILs, I wish I
had spent a few nickles extra to buy snap-on wiring blocks in lieu of
messy solder joins. Blocks would have made updating the SMAILs for
signaling so much easier.

I am keeping everything to the front.  You should probably separate the buses by several inches.  This will vastly reduce coupling of any noise that might be on the DCC track bus.  So far the only problems I have had were high impedance control signals from my panels to my turnout controllers.  This was solved with a capacitor and a low impedance pull up resistor at the controller.  Wire routing did not seem to have anything to do with this particular problem.

Tom,

  Your plan for separating the DCC power bus from the control bus is a good
one - but as Alan said it may be "going too far".  It's a -very- good idea to
not run different buses tightly coupled (such as tie wrapped!) together for
even a short distance but as soon as you get about 4 to 6 inches away
from each other you are fine.  When a bus - any bus - crosses another bus
it is always best to do so at right angles or as close to right angles as
possible (if they are less than a couple of inches away from each other).

  I am not planning on running a continuous fascia bus for the cabs at all.
I've gone with "all wireless" for typical use and will only have a few fascia
panels to use in the unlikely emergency situation where the radio fails.  But
I'm using the NCE system that has a far superior radio.

  What I'm doing is to run my track block bus "directly underneath the track".
They tie together using terminal strips that then go to PSX circuit breakers
that then go to the booster.  The track block wiring is untwisted pairs that
follow the track. 
  The layout is separated into "functional areas" and each area has its own
DCC breaker - that way, if there is a short (caused by an operator/derailment)
the cause and the location are tied to each other and do not affect other
operators who aren't near the cause.  Between those areas  I ran 12awg
-twisted- "main bus wiring".  The longest run from the booster to the end
of any track block is right around 30 feet so I could have gotten away with
14awg - but used 12 for the mains and 14 for the track blocks.  And I color
coded all the wiring so that if you look under the layout you can see "which
wire (pair of wires) is for what" easily.  Yes, I re-used some of the color
combinations ... but one wire is always white so it is "white to white" 
everywhere there is a terminal strip - twisted means it is a main and 
untwisted means it is a track block.  Works for me.

  I'm both crimping and soldering all the wire lugs - but using the Wago 221
connectors for stuff like attaching feeders.  If you use suitcase connectors
make sure you get quality brand and use the 'approved' crimping tool!
  Every physical piece of rail has a soldered feeder that goes down thru the
layout to the DCC.  There are both insulated and non-insulated rail joiners -
the conducting ones are "backups to the soldered feeders" and are not
relied upon for supplying power to a segment of track.  All turnouts are
installed using insulating joiners on all rails. 
                                                                                                    - Jim

On 12/4/2020 8:16 AM, Jim Betz wrote:

Tom,

  Your plan for separating the DCC power bus from the control bus is a good
one

And the amount of separation is entirely up to the builder, as long as there is "some" separation between the DCC buss(es), the data cable, and the A/C power lines.
I have a bunch of modules, when put together makes about a 50 ft by 24 ft layout. I run the data cable against the front, each DCC bus runs under each main line track (mine vary from 2 to 4 main lines plus sidings), and the A/C power runs along the back. The DCC power all gets together in a connector when going from one module to the next, then immediately fans out again.

Peace,
Mike G.