I used 20 gauge wire, as that’s what I had on hand. I soldered it to edge connectors. I don’t remember who made the connectors, but they work great. I ran the panel lights (a pair of LEDs from Radio Shack off the main power wires. That way, the lights change position when I flip the switch 
Oh… I should add that my Tortoise machines have their own power supply. I took one of Bachmann’s train-set power packs and bolted it to my benchwork.
I use #20 wire for my feeders - #20 solid DOES fit through the Tortoise hole. #18 I think would be too big. However, using #20 isn;t a problem, we’re talking short distances here, and if you are switching the frog, there can never be more than one loco on the frog at a given time. If you are talkign about switching an entire reverse loop, I would run a short length of #20 fromt he Tortoise to a terminal strip nearby, and then use heavier wire for the track feed. A reverse loop should have multiple feeders, the same 3-6 feet as recommended for other track.
–Randy
You THINK it’s a lifetime supply - sounds like you bought one of the same 500’ spools at Home Depot that I did. All I’ve reall done is make track feeders out of it,and run one line from my converted PC power supply around half the benchwork to feed my one control panel. And I’m at LEAST halfway through the spool - on a 8x12 layout!
–Randy
You got my curiosity up so I just went downstairs to check. #18 will not go through the little holes. I used #24 and have no problems powering the frogs with DCC.
I also bought the HD spool. For the money, you can’t beat it. However, since Cat-5 is so popular, per linear foot, it’s cheaper than 2 conductor thermostate wire (2 conductor @ $28/500 feet = 0.028/ft/conductor, 8 conductor @ $78/1000 ft = 0.00975/ft/conductor ).
I will concede you don’t need twisted pair, foil insulated conductors for switch machines, but if it’s near the same price overall, why not? The question to ask yourself is, will you need all 8 wires, or only two? There is a break even point around 4 conductors.
Personnally, I don’t think it matters if the terminal block is at the switch or the control station. However, I would not spend the extra money and terminate at both ends. With all things factored in, an ethernet-like wiring setup for the switch machines will be about the same cost, just as flexible, and take up less space. Those terminal blocks are expensive for what you get.
-Tom
To answer your question regarding size of wire vs current carrying capability, most people use #12 gauge wire for the power bus for the tracks, # 14 gauge for the track feeders from the power bus. #12 gauge wire is rated to carry 20amps, while #14 is rated for 15amps. This is de-rated somewhat, as they are capable of carrying a little more, but all homes are breakered at 20 amps for #12 and 15 amps for #14 wire.
Now for switch motors, all you need to do is look at the specs that come with the motors, they will have the current draw/rating on them. They use “flea” power as we say in the electrical business, only milli-amps (ma) of current. #18 gauge wire can carry 10 amps, which is 10,000 milliamps ( ma). So as you can see, #18 gauge wire is gross overkill. #24 gauge will work just fine.
Those current ratings are for 115VAC too. The main issue with using big wire for DCC is voltage drop, not absolute current carrying capacity. There are charts with the loss in ohms per foot of various wire sizes. The voltage drop is a product of the wire resistence per foot, the length of the wire, and the current being drawn - ie over the same length of wire, running a doubleheader with each loco drawing 1 amp will have 2x the votage drop as the same wire but only a single 1 amp loco running. Now, we’re usually talking about a volt or less, with typical run lengths and typical wire sizes. But if you have a run 50’ from a booster to a power district and don’t use #12 wire, and run more than a couple of locos in that power district, it WILL be enough of a drop to make the trains run noticeably slower.
–Randy
Tom, all my mainline tortoise are wired back to Lenz stationary decoders. The reason I chose to use multi-pair cable for my turnout runs, is that I have a large layout and by having spare pairs in place all over the layout gives me the capability to connect future signals, controls, or accessories without having to run new wires/cables. i.e. only short runs of wire from device to spare cable pair. The kind of cable is up to the individual in what he has on hand or prefers to use. Telephone is adequate for the job, but if a person wants individually shielded pairs with ground or fiber optics…what ever works for him.
Over forty years experience in the electronic/electrical fields has taught me never to design or install devices using hard wiring. Plugs , terminal strips, or other intermediate methods of connection is always recommended so that there is an easy disconnect for maintenance or modification. Thus, I use terminal strips at both ends. Some buy the plugs that simply insert on the tortoise connector. Both are good methods.
If you don’t think you will ever need to remove the tortoise or other types of devices, then hardwire them in. I have chosen my way because I know that tomorrow will bring new ideas that usual
Good point Rex. Since all my turnouts are relatively easily accessible, I didn’t bother with a connector at the turnout. I do have connectors at the control panel though.
-T
Here is the data for #12 copper wire: The resistance of this wire is 1.62 ohms per 1000 feet. By doing a quick ratio and proportion calculation, the resistance for 50 feet would be 0.081 ohms. So if your layout had 2 amps being drawn, this would give you a voltage drop caused by the bus wire alone, of .081 X 2A = 0.162Volts dc. Hardly enough to be noticable. But, there may be other factors contributing to lower voltage at the locos. You must take into account all the voltage drops at all the various connections off the power bus, even the soldered connections have resistance. And, what can appear to be a good solder connection can in fact have added resistance. If you want to check this out without actually using locomotives, place a resistive load across the tracks out at about 50 feet from the power source, and check your voltage drop. If you had a perfect bus with no wire resistance, and no solder/t connection resistance, you would only have the voltage drop across the load resistor. We all know that this is not the case however, so what we do read for a drop is the sum of the all voltage drops caused by all the little resistances along the route ( circuit ).
BTW, some real good ideas here in this thread for wiring and connections.
Right. although you need to double your answer - a 50 foot run has 100 feet of wire in it. But this is why #12 is recommended. Repeat the calculation for #18 wire. A lot of people say “but I used #18 with my DC power pack, why won’t it work for DCC”
–Randy
Good idea on the rolls of wire by Rex and Randy. I am about to buy some wire, and after your experience Randy, 500 foot roll will NOT be too much will it!!!
Wow! #14 for track feeders? You must be using code 400 track… (Stops and ponders…) I use #16 for a sub bus network off of the main bus, then use very short runs (less than 1’, most under 6") of, 20 or 24 to the tracks. See Alan Gartner’s website for suggested size wires in DCC. http://www.wiringfordcc.com/track_2.htm He recommends #14 as the largest for G Scale. For HO the largest recommended is #20 and for N #22. Maybe you were talking about the sub bus running from your main bus and I missunderstood what you were refering to???
Nope, I bought a 500 foot rooll of red #12, a 500 foot roll of white #12, and a 500 foot roll of the red and white #20.
Used about half of it so far on the 8x12 part. Wait til I start building around the rest of my walls…
I use DPDT switches with all of my Tortoises. They work fine. I do not use the ones with Center Off feature. Just flip the switch and all works quite well.
The use of heavy gauge bus wire for DCC is to overcome the resistance of nickel silver rail. The longer the piece of rail between feeders, the more resistance and losses (voltage and data).
Now, to route power from either rail to the frog using a Tortoise is a very short distance. Not much resistance. Current is negligible (“flea power”).
I use Romex 12 or 14 gauge for bus (~20’), something like 20 gauge for feeders (~1’), and solid 24-28ga for Tortoise power routing. In some case I’ve used the very small black wire with rail joiners attached (Atlas terminal joiners?) for feeders and/or power routing. No noticeable problems.
I suggest you thing more about soldering the X’s to your DPDT switches. Use shrink tubing to prevent shorts.