Wire for (DC) layouts

 
  Old Northern Locomotive Driver

I have been in the process of building a layout for a year or two now, and I have got to the stage where I am ready to screw down the track (before anyone tries to tell me it should be pinned, nailed or glued, I am using vintage Hornby Dublo 3 rail track, on a tinplate base, which is designed to be screwed to the baseboard).  I will also be wiring the track and accessories at the same time (at the moment my wiring consists of two pairs of wires to terminal rails - obviously a temporary measure).

Now, the thought of colour coding the wiring did appeal to me and, looking through Jaycar's list of wires and cables, I came across this: https://www.jaycar.com.au/light-duty-hook-up-wire-pack-8-colours/p/WH3009 (each of the colours is, of course, also available separately).  I was to go to the nearest Jaycar shop over the next few days to get some, together with a few other bits and pieces until I noticed one thing.  When I looked at the specifications, it said that the cables were rated at 0.6amp.  Hornby Dublo 3-rail locomotives, when they were new, were said by Meccano Ltd to draw a maximum current of 0.65amp.  Added to this is the possibility that the odd locomotive or so might draw slightly more, due to age related wear and tear, although I have overhauled most of them, so this may not be much of a problem.

Although I do understand the basics of electrifying a model railway, my understanding of electrics is somewhat limited, so I was hoping that someone who knows more about the subject than myself could advise me as to the best wire to use and where to get it.  Would I be asking for trouble if I wired the layout using cables rated at 0.6amp when my locomotives could draw a maximum current of 0.65amp?  It seems to me that maybe I should be using wire rated at 1amp or thereabouts, but I don't really know.  Jaycar do have heavier duty cables but, unless I missed something, they are rated at 7.5amp and upwards.

I mentioned Jaycar only because they are the only place in Sydney I know of that sells this sort of thing - if there is somewhere else I should be looking at as well, I would like to know of it.

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  Oscar Train Controller

Hi Old Northern, I've been in a similar boat. I bought three packs of those Jaycar wires and have used one lot and was onto my second using it for everything - slow-mo point motors and relays which is fine, but I'm going to rewire all the bits related to track power.

True, Jaycar only have "light duty" and "heavy" and nothing in between. From my research earlier, particularly on this subforum of RMWeb, most will say "medium duty" hook up wire ie around 21 AWG or 14 strands @ 0.2mm (14/0.2) which is rated around 4A.  That Jaycar stuff is only 13/0.12mm or 26AWG and as you say rated at 0.6A. I haven't had any issues with my modern two rail stuff but I decided a few months ago to change the wiring, just haven't had a chance to do it yet. There's a number of handy tables you can do a google image search of that show wires sizes in amp rating which I referred to as well.  

As far as shops, I don't know what's in Sydney but two online places I've looked at is Wiltronics and Altronics
RS electronics might be a goer too, I haven't looked there. I tried bunnings and did buy some irrigation cable ages ago but it's a pain stripping bundled cables.
  GoldenGirl Locomotive Fireman

Hi Old Northern, I've been in a similar boat. I bought three packs of those Jaycar wires and have used one lot and was onto my second using it for everything - slow-mo point motors and relays which is fine, but I'm going to rewire all the bits related to track power.

True, Jaycar only have "light duty" and "heavy" and nothing in between. From my research earlier, particularly on this subforum of RMWeb, most will say "medium duty" hook up wire ie around 21 AWG or 14 strands @ 0.2mm (14/0.2) which is rated around 4A.  That Jaycar stuff is only 13/0.12mm or 26AWG and as you say rated at 0.6A. I haven't had any issues with my modern two rail stuff but I decided a few months ago to change the wiring, just haven't had a chance to do it yet. There's a number of handy tables you can do a google image search of that show wires sizes in amp rating which I referred to as well.  

As far as shops, I don't know what's in Sydney but two online places I've looked at is Wiltronics and Altronics
RS electronics might be a goer too, I haven't looked there. I tried bunnings and did buy some irrigation cable ages ago but it's a pain stripping bundled cables.
Oscar
Try Element14, this is a link to their cable search page: https://au.element14.com/w/c/cable-wire-cable-assemblies/hook-up-wire/prl/results?st=stranded%20wire Lots to choose from.
  Captainchoochoo61 Locomotive Fireman

In a previous life I did deliveries to building sites. On the rubbish heaps were always various lengths of household / alarm/ irrigation wire.
As it was free I collected lots.
Over time I used red / black and orange/  green  for my two independant circuits.

When it came to accessories, signalling , sensor wiring I used rolls of hook up wire. It was fine and the .65 amp was never threatened.
The layout was on several modules and had plugs on each end , and these were wired with specific locations for each circuit eg a1 and a2 for the red black track power etc.

This made chasing back to remedy problems very easy. The overkill of 10 amp wire made things reliable.
One area where hook up wire was inadequate was on points that were a long distance from the CDU supply.
Originally I solved the problem by doubling up , but in the end I bought a roll of heavier duty orange wire and that became the norm.
Then the points threw with a bang. !!

So when I had the feed wires sorted I used the light wire to feed up to the track. I normally used a deep purple so it looked like the dark wires the railways used, so sometimes I could run some around to battery wells, just like the real ones.

Another use for the 10 amp wire was for trees. Stripped or un-stripped wire could be made to a tree as the base was always widest, then would have branches twisting off to reduce thickness towards the ends. We used a styrene, non toxic, waterproof but flexible compound to make amazing trees

And small scraps could also be used to join sections of track if the fish plates were suss.

You have been given some links and places like Atronics, Jaycar, and sound shops all carry various weights. And they usually have plenty of colours to choose from.
If you will be considering DCC in the future I was advised to avoid bundling track power together as the signals could become confused, so for me I pinned it out under the layout with some separation. It also made it easier to solder in an extra dropper.

Another thing I always advocate for is modular layouts. During the building process if you can turn over or through 90degrees each section your back and forehead will be much better for it.
One friend had a twenty module layout with common sizes. He built a stand able to rotate so he could stand or sit while working UNDER the boards.
Old style track may be a bit harder to place over joins, but consider it if you can!!
  Old Northern Locomotive Driver

Thanks everyone for your suggestions and information.  I had a look at the various sites mentioned and ended up purchasing all that I need (or at least I hope it's all that I need) from Altronics.

The layout is on three boards which, when joined together, give a total size of 8' x 4' (or, if you prefer, 2440mm x 1220mm).  The wiring will be colour coded and there will be plugs connecting the wiring between the boards..  I will also be using tag strips for where one wire has to branch out in two or more directions

I won't be using DCC, either now or in the future though.  I have at least 45 locomotives (it's a while since I counted them - I could have more) the majority of which are around 60 to 70 years old.  I do not have the time or the money to spend on converting a stud like that (assuming they can be converted) and, in any case, the aim of the exercise is to produce a layout along the lines of what we saw in the late 1950s/early 1960s, although I do plan on using modern materials for what scenic treatment there will be.
  Old Northern Locomotive Driver

Just to round out this thread, here's a corner of the layout as it stands at the moment.  The track is not fixed down yet but is in its final position.  The wiring presently consists of two pairs of wires going from the controllers to terminal rails, but that will soon change, as can be seen from the bundles of wire in the photo.  Once the wiring is in place the electric points and signals and other accessories should all spring into life......


  dthead Site Admin

Location: Melbourne, Australia
Sorry OldNorthern the link does not work for users not on that website, maybe. I tried some variations to no avail.

Regards,
David Head
  xdford Chief Train Controller

Although the wire is "rated" at .6 amp, nearly all devices and utilities such as wire have a safety factor or safe working limit. SWL and a number of tons/tonnes is a common marking you will see on the sides of cranes for example.

The maximum load any device or wire will be a figure of at least 3 times the specified rating and often 5 or more depending on the application Therefore you should not be seriously overloading the wire with your current draw even if those old Hornby motors have got heavier on the current draw.

So in my opinon, do not get too concerned at this point and use what you have unless your controller is literally miles away from where your trains will run in which case the thicker wire will be an asset to you,

Hope this helps,

Cheers

Trevor
  Aaron The Ghost of George Stephenson

Location: University of Adelaide SA
The 0.6A figure isn’t there for a safety rating, it’s there to allow for sufficient performance.

That wire runs at a linear resistance of 136mohms/m, a 10m run (5 out and 5 back) has a resistance of 1.36ohms. At 1.8A (3x rating) you’re losing 2.5V. Put 3A through that, (5x rating) you’re going to lose more than 4 volts...

Suddenly your ‘12V’ controller is an 8V controller.

That is before we consider what the drawing of that current through the wire is going to do to the temperature of the copper - further increase of resistance, hence further decrease in voltage at the load.

Stating that you can pull significantly more current than rating through a wire is to completely misunderstand the physics at play.
  Old Northern Locomotive Driver

Sorry OldNorthern the link does not work for users not on that website, maybe. I tried some variations to no avail.

Regards,
David Head
dthead

It worked for me and I incorrectly assumed it would work for others, but it seems that it only worked for me because I am registered on the forum where I originally posted the photo.  Sorry about that.

The photo probably isn't really that important to the thread, but here it is anyway, after I uploaded it to a Flickr account I no longer use (that was an interesting exercise in itself, as I had forgotten the password and the recovery email is no longer current, but I digress....)



The wire that I ended up buying from Altronics was rated at 1.5 amps so, given the last two comments in this thread, it should be more than enough for what I need.
  xdford Chief Train Controller

The 0.6A figure isn’t there for a safety rating, it’s there to allow for sufficient performance.

That wire runs at a linear resistance of 136mohms/m, a 10m run (5 out and 5 back) has a resistance of 1.36ohms. At 1.8A (3x rating) you’re losing 2.5V. Put 3A through that, (5x rating) you’re going to lose more than 4 volts...

Suddenly your ‘12V’ controller is an 8V controller.

That is before we consider what the drawing of that current through the wire is going to do to the temperature of the copper - further increase of resistance, hence further decrease in voltage at the load.

Stating that you can pull significantly more current than rating through a wire is to completely misunderstand the physics at play.
Aaron
Aaron, actually I understand very much the idea of voltage drop and the physics of it - I understood the initial question to ask recommendations because that .65A was too high a current and therefore a problem for .6A rated wire.. Would a 5 metre run be necessary each way?

The effect would be not only 8 volts but somewhat lower given the inductive load of the Hornby motor at such a distance drawing maximum.  I seem to remember that the 0-6-2 tank could run very fast scale speeds so maybe that 8 volts would be OK.  If our OP is using original Hornby controllers, those devices worked by "starving" the motor of current at a 12 volt rating rather than purely controlling voltage output as our later controllers do.

So if I misinterpreted the question, I'll wear that but there are elements where we are both correct there... for what its worth!

Trevor
  Old Northern Locomotive Driver

I seem to remember that the 0-6-2 tank could run very fast scale speeds so maybe that 8 volts would be OK.

Trevor
xdford
They go ridiculously fast.  I haven't run both side by side to see how they compare, but the 0-6-2T seems about as fast as an A4.  Even at those speeds though they tend to stay on the track pretty well, probably due to their weight.  The only incident I have had so far was when our younger grandson turned the controller to full speed when I wasn't looking and my Duchess of Atholl became airborne on a curve and landed on the carpet.

If our OP is using original Hornby controllers, those devices worked by "starving" the motor of current at a 12 volt rating rather than purely controlling voltage output as our later controllers do.

Trevor
xdford
No, I'm not using original Hornby controllers.  They were excellent in their day, but their day is past.  The rubber insulation on the internal wiring would, with the passage of time, have deteriorated to the point where they are no longer safe to use, unless they have been rewired by a competent electrician.  I use a Gaugemaster Combi which, in spite of the output only being 1 amp, seems to work perfectly, even when the locomotive is running for half an hour or so.

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