I’m starting an 8’X17’ layout with a five track classification yard and a switching area kind of like a time saver puzzle and at least 29 turn outs. ( the Warbeek and Sunmount from “Track Planning Ideas-58 plans” by Kalmbach Pub./page 32.) with some slight changes. (increased radii and lower grades) due to longer room length…
How do I predict/plan how much wire I’ll need for DCC bus(ses)? In the past I built snap track plans with the materials needed, listed. Workin’ “blind” and inexperienced this time.
I’d like to buy all of my wire now while I’ve got some dough and before prices increase. How many feet/spools would be a sure bet without having way too much left over?
Recommendations for cheapest prices/good quality wire would be appreciated as well.
The DCC Control bus should run along the usable perimeter of the layout so that you can add jacks for throttles wherever you’d like. Leave a bit of slack so you’ll be able to add jacks in the middle of the lines.
The DCC Track bus should pretty much follow your main line around. You can run your feeders to both the main and any sidings off of that. You might want to isolate your yard with a circuit breaker, so plan for a few feet of extra bus to do that.
Feeders should be placed every 3 to 6 feet. You’ll need a couple of feet of wire for each, and two wires for each drop (both sides of the track.) It’s probably a good idea to put a feeder pair on each yard track and siding, too.
Each powered turnout will require separate wiring from the switch machine to whatever you’re using for a control panel. Some like to have the controls on the fascia along the perimeter, close to the individual turnouts. Others prefer a central control panel. For twin-coil machines (Atlas, Peco) you’ll need 3 wires for each. The best solution I’ve found for this, by the way, is to get 4-conductor (2 pair) telephone wire at Home Depot. Remember that you’ll need to run power to the control toggle from somewhere, too.
Then, there’s structure lighting. I have a number of different structure lighting busses - a couple for buildings, one for street lights, one for the subway stations, another for the LEDs in the subway tunnels, one for the yard tower lighting, etc. If you have illuminated buildings and towns like this, you’ll need more than you would expect.
Neatness counts. It’s better to run your wires neatly along and across supports beneath the layout, using a grid pattern rather than cris-crossing diagonally from point to point. Do as I say, not as I do. With all good intentions, mine is still a mess like this underneath. Maybe because it will add as much as 50% more wir
The track bus can be AWG 12 and follow the main line, but if the main is twice around, the track bus only has to go once around. This can be solid or stranded.
Feeders. I do mine a little different that most. I have a roll of AWG 22 solid, bare wire. I solder a short piece to the rails, then feed it down to underneath the layout. Then I make a loop using needle-nose pliers. The loop winds up being almost tight against the bottom of the sub-roadbed. Then I use another wire, AWG 18 solid (thermostat wire) and solder one end to the AWG 22 feeder loop and the other end to the track bus. It’s a little extra work, but the wire that attaches to the track is smaller and shows less. I feed every six feet or so, and solder the rail joiners in between.
Telephone wire is good for turnout control. Cat 5 cable is also good. It is about the same AWG as telephone wire but has eight wires per cable, where telephone wire only has four. If you just buy Cat 5 cable and get a good deal on it, you can double it up for longer runs to carry more current. Or you can use one section of cable to control two turnouts.
I have found that buying the wire in rolls is cheaper than buying it by the foot. You may wind up with more than you need, but you will have it for later on. On my last N scale, DC layout using cab control, I used about 2000 feet of wire for a 10 x 13 x 2 ft wide layout where the main line went twice around the room. I know this because most of the wire used came from two 1000 foot rolls of AWG 18 stranded, and I still have some of it left.
Check the Internet for some good deals. The below companies are the ones I try first.
I don’t run DCC, so my track power requirements are somewhat more wire-intensive than yours. My suggestion is to estimate the amount of wire of each size you will need - and then double it. What may be left over after the initial wiring is complete will gradually be consumed as you add a turnout here, a mechanized gadget there, street lighting in your town…
As you wire, test everything right away. That way, slipups will be caught and dealt with retail, not wholesale.
When you start adding ABS and interlocking signals, any wire you have on hand will evaporate quicker than a rain puddle on a windy day in the dessicated desert.
A key factor - measure along the actual wire route, not directly from panel to gadget. That z-shaped route may prove to be up to 70% longer than it appears at first glance.
One final note. Label and document EVERYTHING. The information will prove invaluable when (not if) the need to troubleshoot rears its ugly head.
Chuck (modeling Central Japan in September, 1964 - with LOTS of stud-and-nut terminal blocks)
I’ve never bothered to estimate the amount of wire I would need in advance. How you wire is going to have a big impact on how much wire you will use. Key things to decide in advance:
DCC power bus: Are you just going to do one loop of the layout, and have slightly longer feeders? Or are you going to run a power bus under every track to have shorter feeders? Will there be more than one power district (each power district has its own power bus)?
documenting/tracking: Do you plan to strictly color code every wire type (N rail bus, S rail bus, switch machine common, switch machine normal, switch machine reverse, structure 1st leg, structure 2nd leg, etc)? Will the color coding be strictly enforced throughout the life of the layout? Or will you use a combination of labeling, color coding, and diagrams (as most eventually do)? The ability to somehow know what every wire under the layout does (or is supposed to do) is priceless in terms of your time. Don’t ask how I know this. Strict color coding is more expensive, but is often the simplest method to track wires.
central or local control: Local control means walk around throttles and radio receiver and/or throttle plates - the latter requires a throttle bus to the throttle plates. Control of turnouts and uncoupling ramps (if not permanently fixed magnets) should be central or local, just as throttles are.
For the DCC power bus, many use household Romex wire because it’s relatively cheap and more than big enough. In DC, I used braided 16 gauge antenna wire for a looped common return around the layout.
I used 26 gauge magnet wire for feeders with DC. Since I did not have space for more than an occasional double heading of small locomotives, and every rail piece had a feeder, the 26 gauge was adequate. The magnet wire is relatively cheap, and next to invisible soldered to the rail. On my
Based on my experience from my test layout, and from my experience running “real” electrical, here are my suggestions for what ever they’re worth.
For the main line bus (heavy guage, 14 or 16 minimum I’d think) measure your mainline (and any branchine mains), and than double that amount. Should give you enough to cover yards and sidings, and have enough to correct if you need to.
Example - 100 foot mainline - 200 linear feet to purchase.
For the feeders, (slightly smaller guage, 16-20 gauge) divide the same distance by three. Take that number, and multiply by 10 ( to represent the average feeder length of wire), and convert to feet. I would similarily double it for additional feeders or mistakes as needed.
Example. 100 foot mainline - 100/3 - 33 feeder drops - 330 inches of wire - 33 feet of wire - 66 linear feet to purchase.
I also recommend new wire if possible, used can cause you unwarranted grief down the road, and ultimatley may not save you any money.
Some folks might think my doubling is extreme, but I’ve run enough electric to know that you never have enough, and nothing is more frustrating than having to stop a job and come back because you ran out.
Don’t forget other items like bus strips (useful for branchlines), and connectors (those suitcase connectors are pricey, but work VERY well), and some system to connect the wires to the undersurface (My staple gun has a built in staple setting for wire that produces a nice clean “bump” - very useful, and fast.
No matter how much you think you are going to need, chances are you’ll still need more. Why? Because you will probably make some changes as time goes by and those changes are probably going to be wire intensive.
Sure, it’s a good idea to buy all you’ll need when prices are reasonable but you can’t always count on that. But what you can do is by it in the biggest rolls that are available. Also color code your wiring so you are going to need the wire is several colors.
I use DCC and am building a large layout. I would agree with the above comments that you will need at least two 12ga buss wires the length of your track, and then some.
I buy my 12ga wire in 500ft contractor spools from LOWES, Home Deport or Menards. It is about 1/2 the price of buying wire in smaller lots. In addition LOWES peridically runs ads with $25-$50 off home remodling projects when you spend at least $100.
I wired a 20 x 40 foot HO scale club layout for DC / DCC operation. The amount of wire that was ultimately used must be well over 5 or 6 miles, in addition to nearly 200 block toggle switches on various control panels.
If the layout had been wired for purely DCC operation, there would probably be less than 500 feet of wire and no block control toggle switches.
Initially, the layout was also wired for a controller bus with 12 outlets around the fascia into which the hand-held controllers could be plugged. That required Cat V wire to every outlet.
We have since changed over to the NCE ProCab Radio system and don’t use the LAN at all anymore.
If we were building the layout today I would wire it for pure DCC operation and Radio throttles. No controller LAN, no toggle switches, no control panels, and miles less wire needed.
Thanks very much guys! I still can’t believe there isn’t a book available that outlines, specifically these kinds of basic considerations. They tell you what’s needed but not how to figure or assemble a needed materials
list/quantity.
I don’t mind having more than I’ll need as I know I’ll make some mistakes but I just didn’t want to end up
with a LOT of extra I’d never use. Your posts are giving me a better idea of how much I’ll need of the various sizes needed. I’m “hip” to the need for specific gauges and keeping colors coded and uniform throughout the layout. Things like alining them in grid form, etc. are new to me and helpful.
Keep it coming if there are new posters with good advice and experience or as new thoughts occur?
I’ve almost got the back drop up and finished. Bench work will begin in a week or two. I’d like to start purchasing wire as I begin the bench work and before my wife sees the credit card bill
Be prepared for sticker shock when you start looking for wire. I recently purchased a 50 foot hank of 16 gauge stranded speaker wire at K-mart and it was $22. Two years ago that same hank was less than $5.
