wire size requrements for DCC

Model Railroader Electronics and DCC
1

I am just getting back in the Hobby after 35 years or so. After some research i have purchased an NCE Power Cab starter system. I am in the process of building an HO scale layout that will represent a division point. From the main yard area my power will have to reach 30 feet in one direction and 25 in the other.

My questions are:

1 What size wire do i need for theses size “bus” runs? The NCE is a 3 amp system

  1. Should I connect the smaller feeder wires directly to that size bus or will I need an intermediate step?

  2. I plan to run a smaller size wire off the main “bus” into the yard areas and run the feeders to that because of the number on connections. Is that a good idea?

I remember the horror of wiring a layout for DC in the late 60’s even with my Grandfathers help. This seems much easier.

Thanks for the input!

Jeff

2

I would use 14 gauge as your main bus wire. I personally use solid core wire as its easier to strip when I solder my feeders to it (the stranded tends to fray a little) however stranded is easier to “pull” into place

My feeders are all connected directly from rail to bus. no intermediate step. My feeders are stranded wire ( found a bundle of 2000 prefabbed 11" twisted pair red and black 18-20 gauge feeders(not sure exactly the guage)) . All i have to do is strip the ends, tin and drop them in. I tin all my feeders before they are installed.

I will used 20 or so guage solid wire when I run out of these prefab feeders

The reason I would use solid wire (I tin all my feeders so they act like solid wire) is that I create a L shape in the wire to create a mechanical joint against the rail. This keeps the feeder in place even before I solder the joint.

I would run a separate bus for your yard just in case you decide to make it a separate power district in the future. My yard has a separate bus as I several circuit breakers around the layout. I use these so that if the yard operator shorts it doesn’t shutdown the whole layout.

DCC has greatly simplified wiring.

I hope this info helps.

3

Jeff,

  1. As previously mentioned 14AWG would be fine. It’s easily obtained and relatively inexpensive (as wire goes…). Solid or stranded is your choice. For DCC purposes, there really isn’t any electrical difference between the two.

  2. You don’t need an intermediate step, but whether or not you use one depends on how you eventually set up your wiring. In my case, I don’t use any intermediate steps because it was just easier to extend the “main” bus, or branch off it using the same wire gauge/color.

  3. This is really just a specific application of #2, and the answer really depends on the current draw the yard (and therefore the run of smaller wire) will see. If it were me, I’d just go the same route as I mentioned in #2. And as a matter of fact, that’s exactly what I did for my yard. The feeders are fairly close in a yard, so it’s not a big deal to tie them into the bus.

4

Between that COdy’s Office episode and the recent articles on wiring in MR< I REALLY hate that intermediate wire step - all to make it possible to use suitcase connectors. They coudl solder that #20 feeder right to the #12 bus and be done, but instead you have to get extra wire AND TWO suitcase connectors for each and every feeder wire. A complete waste.

–Randy

5

Thanks for the explanation, Randy. I never could figure out the reason for the intermediate wire. i’ve been using 24 gauge wire from rail to bus for over ten years with no issues. Of course, I have always soldered my connections, and never thought about using connectors.

Errol