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13 Responses to Model Railroad Wiring
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Not having seen other comments, I would suggest that “it depends.” With only 1-2 A of current and non-hazardous voltages, probably 16 GA stranded would be enough unless you are travelling long distances. Unlike house wiring, the common is usually done with black insulation while the power side might be red. But then you have to decide if the power wires to switches or signals should be a different color, since that is usually a constant higher voltage. Also, if you have traditional DC power vs DCC you may have DPDT switches to reverse direction on isolated blocks…should you retain a “common” color for one of those wire pairs?
Stranded or solid is irrelevant unless you are going to flex the wires a lot…disassembling between baseboard modules, for example. Likewise tinned or bare copper is irrelevant unless you run your railroad by the ocean!
I have used .75 square as a bus bar. This the standard car wire, with 6 core alarm wire from this, as low amps are used. European wiring.
use telephone wire
i saw it on a video and it works really well and you only need two out of the like seven wire that come in the roll
totally agree with you andrew, telephone wire is 12 volt and low amps. being solid core it does add some resistance which helps preserve lighting circuits. although , using required resistors is still recommended.
if you see telecom lorries (carrying poles) and can speak to them they will usually give you quite a lot of discarded wires.(ask them nicely) these are multi core and colour coded.
they are also pretty rigid and can be shaped for layout installation quite easily / tidily.
I have been using outside telephone wire and I haven’t had any problems yet. Plus I have been using terminal strips from radio shack instead of Lowe’ improvement. Their cheater,but are the same thing.
All I can share is what I did, I also had the advice of a friend who is both an electrician and master model railroader…
My main DCC bus is 12 gauge wire, red and black solid core wiring
Off of that I tap into the DCC bus where needed with 16 gauge wire, in some places those go directly to 22 gauge drops off of track but more often the 16 gauge goes to wiring terminals in congested areas.
Then I run 16 gauge from wiring block to multiple drops of 22 gauge, I use a new and somewhat obscure product called posi taps, instead of soldering or crimping you just put the wires into the fitting and screw it shut
I have no relations with the company other than being a happy customer
I also have a 12 gauge DC bus for lighting up buildings and feeding DC to things like tortoises
Matthew
I agree with Mathew. color separations for power important 4 the dif sizes. 4 examp =red/blk, wht/grn, blu/brn
In general the larger the diameter of an electrical conductor the lower the resistance therefore a lower loss on the cable and higher current capability. You are set on the Voltage [V], assuming something like 12-18V max (AC or DC doesn’t really matter too much for now). It is the current, measured in Ampere [A] that is of importance and that will give you your minimum diameter or gauge of wire. If the consumption is given in Watt [W] you have to divide Watts by Volts to get Amps; eg 0.9W (or 900mW) / 12V= 0.075A (or 75mA)
You will have to determine what current you are using by adding all user items. For example: if you use 100 little lamps for house and street lighting (easily reached on a medium layout) with 0.1A each that will give you 10A so you don’t really want to run all of that together on phone wire but use something rated for 10A for the bus/distribution and use the thin wire only to feed single lamps. For feed in points for the track, eg at the back of the layout I am generous on the diameter to 2.5 even 4 square mm to minimise any loss from controller/transformer to track. A few meters of really thin wiring on low voltage can result in losses of 10-15% (very rough example), meaning your engines get maybe only 10.5V – and if that’s on an incline with a double header at a tricky part of the layout with oxydised track you’ll have issues.
If you’re doing something that ends with or above 10A current (which on 12V DC is only 120W) do check the actual plan with someone before you turn on, you are starting to deal with serious current. I also got myself a regulated power supply which shows voltage and current which has the side effect it is good for testing new sections and shows any shorts – speaking of which, to avoid burned out wiring, layout or worse in case of error or fault: put in a couple of suitable fuses, eg from car inline electrics, they are designed for 12V systems and yes, what is suitable for a car is okay for a layout – I’m talking normal electrics, not car stereo.
But apart from the wire ensure that connections are solid! It can be more than troublesome to have loose or unsafe connections even in low voltage circuits. I solder and insulate connections wherever possible, especially track, and use proper terminal blocks, insulation tape, heatshrink, switching gear etc. Apart from losses on bad connections or intermittent function keep in mind that although you may not get badly hurt by low voltage – it still is electricity and bad connections and sparks can seriously heat up can cause fire.
If you’re running DCC do yourself a favour and treat it for what it is – a computerised system: run it all of powerboard with fuse and surge protector. Your $1000 engine will be greatful the day after the electric storm!
Happy modeling!
Use solid or stranded, copper wire. Electrical wire is made in many sizes, the size is the diameter, and each different size is assigned its own “gage” number. The larger the gage number, the smaller the wire. For example: gage 22 is smaller than gage 20, which is smaller than gage 18. The gage numbers are even until the size gets larger than gage number 4. The size of the wire needed for any circuit depends only on current, measured in Amperes, sometimes abbreviated as Amps, or properly just “A”. The maximum A of current allowed to be safely carried by each gage is listed in handbooks and on-line. The lower the gage number the higher the current allowed. For example, the maximum for gage number 18 is 8A, but for gage number 12 is 20A. Insulation on power wire is to provide protection from shock, but your skin is an insulator for up to 40 V, so for model trains running at the normal 20 volts or less, insulation isn’t needed to protect you from shock, but is needed to provide isolation from wires in other circuits (track, switches, accessories). So, after all that, use whichever wire size is large enough to carry the amperage of the circuit you intend to use the wire. For almost all model train layouts, the circuits are carrying less than 10 A, so wire size 16 is sufficient. Size 18 or even size 20 is plenty large enough for the “average” layout that isn’t bigger than 8′ x 4′ and running no more than 4 engines at a time.
Thank’s for all the comments on wire.
John.
The future is computeized DCC using a wireless system including cell phones. Using side.by-side solid core wiring creates noise with or without wireless. The track buss wiring should be twisted to avoid noise interfering with the decoders and covered solid wire makes this twisting difficult. As more and more wiring is added for all accesories, this becomes a driving factor with DCC electonics.
In our modular system layout, we use 14 gauge solid with 16gauge feeders every 3 feet per track. For connections between modules, we use computer style keyed molex connectors and solder each crimp for improved connectivity. We run 100+ feet with no drop in power or DCC signal.
I use a 7x.36 standard house wire red and black as my main 12 volt supply which is run under the base boards and use a thinner stranded wire from this main wire to the track (no more than 6 inches in length) so that it can be hidden in the ballast easily. I also use a combimation of colours for signal, relay, structure lights etc so that it is easier to identify which circuit I am working on. I also built my own power supply that has 9 different size transformers and rectifiers and capacitors to supply the different circuits. (This is something that you will need to know how to do safely so being checked by a registered electrician is a must) Until now my layout has been DC but shortly I hope to go to DCC operation once I learn more about this mode of operation.