# Bus line wiring question...



## afboundguy (Jan 10, 2021)

I did a quick mock up of my layout and I've started laying and gluing track and I have been adding drop wires to connect to the bus wiring but I have a quick question about how to run said bus wiring. I was thinking of starting the bus wire run at the bottom left side at the X and running it all the way around where the orange arrows are pointing and then have it finish at the large yard on the left side. (I've attempted to mark the bus line path in black) My main question is about the blue arrowed area. I already know I'll need to add several auto-reverse loop circuits and since I'm planning on doing that can I just tie into the main bus wire without any issues or would I just reverse the black and red wires opposite to the other 2 tracks wiring?


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## afboundguy (Jan 10, 2021)

Along the same lines besides the yellow X would I put AR1's at 1&2 or at 3&4?


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## DonR (Oct 18, 2012)

You want an even distribution of your DCC power.
In your situation, that would seem to indicate that you
connect your DCC power to your bus at a central point
in the layout.

You would have a reverse loop controller for
each loop. The INPUT power for each reverse controller would
be from the nearest DCC bus. Polarity does not
matter. The OUTPUT of each
reverser would feed it's isolated section. You
would not connect the bus to isolated sections.
The reverse loop controllers will
match phase automatically in your isolated sections.

Don


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## OilValleyRy (Oct 3, 2021)

I agree with Don. Unless using NCE PowerCab, put the base station as central as possible, have two shorter bus lines going both directions.

I’d probably insulate at 2 (diverging side) & 4. You might have a problem at the chimney though. The two reversing loops coming together. I’m not sure if two AR1s can be wired to the same block. You may need to insulate rail shy of where the 3 become one? I’m not really sure about that though.


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## DonR (Oct 18, 2012)

It is generally advised to never have two
isolated reverse loops abut. There should be
a more than locomotive length between them.

The reason is that each reverser would try to
match phase and that would cause a total
mismatch short circuit while the loco wheels
spanned the insulated joiner.

Having one reverser controlling two isolated
sections can also result in unwanted short circuits
when two locos enter each of the two isolated
sections at the same time.

Don


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## CTValleyRR (Jul 26, 2014)

The bus does not have to trace your track. If you want to start the bus in the lower left, just run it in a big C shape under the layout, it does not need to go back to the left again. Wire all feeders to the bus, including those going to the reversing loop controllers.


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## afboundguy (Jan 10, 2021)

@DonR @OilValleyRy @CTValleyRR would something like either of these work? I would then just tie into the loop around the chimney with the same polarity as the other outside lines that are one big continuous run and then the AR1's would work their magic when needed?


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## Stejones82 (Dec 22, 2020)

Some rough dimensions would help. How wide are these tabletops? 

I think you can run a single bus under each table and tap feeders and the power-supply to you Auto-Reversers as needed. 









You can put the command station at the end, but better to place in the middle so that each 'run' is shorter in distance from the CS/booster. 

Insulation Displacement Connectors (IDC) T-Taps are great! I am using 16AWG for my bus and 20AWG for feeders. My layout is small. I use 3M 905 IDC connectors to connect feeders to the bus. 

Hope this helps.


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## OilValleyRy (Oct 3, 2021)

I’d run DCC bus as SteJones indicated with the *red* line. Feeders tapped off of that for everything except the inner horseshoe loops, which are fed by AR1s. You could put an S curve in the bus on each side if you wanted. I.e. shoot just beyond the chimney then turn 150 and bee line toward your lower stairs area. Same on the yard side kinda, stay between the four mainline, then bee line toward the stairs (accounting for yard ladder controls) and, if desired, hook the very end toward the aisle but probably not needed. 
Just cap the bus ends with wago type connectors.


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## DonR (Oct 18, 2012)

Yes, as the others have agreed, you would get best
even distribution of power when your bus is fed
at a central point, just as you indicate in your latest
post. You are also
right in showing that the two ends of the bus do NOT
connect. 

Connect the input of your reversers to the nearest bus.

Don


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## CTValleyRR (Jul 26, 2014)

I agree. The sketch in post 8 is what you need to do, although I too would recommend using an undulating pattern rather than a straight run.


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## afboundguy (Jan 10, 2021)

Ok so what about this then? And if I took the area in the yellow on the left I would wire the 4 mainlines just like in the picture correct? (the gray lines at the bottom simulate them looping back around at bottom left of diagram...


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## afboundguy (Jan 10, 2021)

My only other hang up is if it matters which side the red and black wires connect to the loop around the chimney? For some reason I can't grasp my mind around which way to run them? Does it not really matter as long as I have them consistent around that loop section? As long as the places where there would be a reverse loop are properly insulated and wired with AR1's does it matter which rail I put the red and black jumpers wires as long as they're on the same rail around said loop section? I do have the section where the green is marked already insulated with plastic rail joiners. I don't know why I can't grasp this and it's starting to drive me nuts but everyone has helped a ton with their replies as I used to be frustrated with other aspects of wiring!


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## DonR (Oct 18, 2012)

The drawing of the tracks 'around the chimney' are not
clear. There appears to be an interconnection with one
or more of the 'isolated' reversing sections. So can't make any
suggestions about how it should be 'isolated'.

Ordinarily you should wire the tracks 'around the chimney'
as you do the rest of the layout, red on the outside rail, black
on the inside rail. However, that may change after seeing
the actual track plan better. 

Don


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## DonR (Oct 18, 2012)

Regarding your question in your post #12.
That is ts the way I would route the DCC Bus
in the LEFT hand section.
All tracks that are not in an 'isolated' section
would be connected to the bus.

In the RIGHT hand section, all tracks except
those in an 'isolated' section would be
connected to the bus. Also connect the
input of the reversers to that bus.

Don


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## OilValleyRy (Oct 3, 2021)

Regarding the inner two tracks for horseshoe curve, which are insulated… bus feeders should go to the AR1s. Then from the AR1s to the tracks. One AR1 per track, not both to both. 

Historically I always did Right Rail Red because it’s easy to remember. It coincides with DCC decoder wire color format too. The other way to look at it, especially from below is Red = benchwork edge/aisle side rail. Black toward the center of the benchwork (not room center).


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## afboundguy (Jan 10, 2021)

Red right rail works for me! That sort of stuff always sticks in my mind!!! 

As far as insulating does this look good where the pieces of tape are or will I need another insulated spot in the 2nd picture where I'm holding the pen on the track? (ignore the take on the 15-16 inch curve I don't think I'll need it insulated there)


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