Installing the Track Power Buss
Getting sufficient "juice" to the tracks is important for successful operation with DCC. Key to that success is what I call the "track power buss". This is simply two wires that run underneath the module from one end of the module to the other. At each end, you wire in your favourite connector plugs so that you can easily connect the track power buss to the next module. Here's a picture of what we're talking about.
You can see two sets of yellow and red wires that are hanging loose that I've labelled "pigtails". These are simply a piece of 18 AWG yellow wire and a piece of red wire that I soldered and shrink-wrapped to each of the corresponding track buss wires. I usually install the pigtails about every two feet along the track buss. The pigtails make it easier to solder the track feeds to rather than trying to solder them to the track power buss that has been snugged against the underside of the styrofoam
I've fabricated the buss wire/pigtails at the workbench and installed them on the bottom side of the module using some wire staples to hold everything in place.
You can also see some of the tools I use. From left-to-right:
Wire Thickness - AWG
Because DCC uses a high voltage and amperage compared to analog or DC operations, the thickness of the track buss wire is most important. In North America, this thickness is specified in terms of AWG - American Wire Gauge. With AWG, the higher the number, the thinner is the wire. For example, 24 AWG wire has a cross sectional thickness of 0.20 square mm whereas 14 AWG wire has a cross sectional thickness of 2.08 square mm - a difference by a factor of 10. This means that more "juice" is able to flow down 14 AWG wire than 24 AWG wire.
Your DCC operating manual typically specifies a minimum wire size of 16 AWG for the track power buss. Current wisdom on DCC discussion forums advocates a minimum of 14 and even 12 AWG. This is a case where bigger is definitely better.
You might be used to using colour-coded telephone wire for your analog operations. This is typically 24 AWG wire. Take all of this wire and junk it! It won't do! Even for track feeders. This thickness is 1/10th the cross section of 14 AWG wire. With DCC, we're pumping 16 volts and 5 amps into the tracks at all times. Anything that impedes the flow of this current into the tracks will reduce the effectiveness of your DCC system.
Installing Track Feeds
Once the track power buss with the pigtails has been installed on the underside of the module, the next step is to install track feeds. I like to colour code my wiring. In this case, I've cut about a dozen pairs of 20 AWG stranded wire. I use a wire with a white insulation for the bottom rail and a red insulation for the top rail. I've stripped and tinned about 1/4" of each wire, then bent the wire so that it fits snugly alongside the track. I've drilled holes on the outside of each rail through the roadbed and styrofoam. I next threaded each wire through it's respective hole and soldered the bent part of the wire to it's respective track.
Here's a schematic of what I've done.
But we're getting ahead of ourselves. The photo below shows the installed track feeds soldered to their respective rail and hanging below the underside of the module. All we need to do now is solder the track feeds to the ends of the closest pigtails.
Soldering the Track Feeds to the Pigtails
The next step is to gather the track feeds to the nearest pigtail, cut strip, solder and shrink-tube the track feeds to their respective pigtail. In the photo below, we've gathered the red track feeds to one of the red pigtails and the white track feeds to the yellow pigtail (because that's the colour scheme I wanted to follow).
Here's another photo which shows things a bit more clearly.
And this is what the final job looks like. From start to finish, it took me about 30 minutes to fabricate the track power buss and pigtails, and an hour to install the 12 pairs of track feeds and connect them to the pigtails.
On the next page, we'll show you some tips for wiring turnouts.