Best sizes of wire for track, switches, and signals?

Terminal block and track power feeds, I'm using this 14ga speaker wire from Monoprice.com. Track feeders are GarGraves 16ga wire pre-soldered to track pins.

Switch motors are wired with 4 conductor 22 gauge wire. My switch motors are powered by a separate transformer, not track power. The DZ1000 switch controllers come with 22 ga wire already attached.

As a FYI, the MTH AIU won't accept wire sizes larger than 22ga. I tried 20 ga, no-go.

See wire photos and size uses .

Transformer to terminal blocks - #14 (OGR wire) The OGR wire is good stuff, especially for DCS.

Terminal block to track blocks - #16 (OGR wire) I used MTH terminal blocks. They are also very nice.

Accessory transformer to switch machines and also switch machine to switch controller - #18 (thermostat wire, Home Depot/Lowes) Pros - Readily available with multiple number of conductors (2,3,5,7,8 etc.) reasonably priced, available in spools of several different lengths. Cons - Solid wire, not the colors I would have chosen for the 2 & 3 conductor versions. However, the solid wire actually became a plus when wiring my Atlas switch machines, no crimp forks required, just a loop in the wire around the screw.

Lighting and other accessories - Some #18 thermostat wire, others are a mixture of anything from #18 to Cat5 cable (#24) depending usage, device type, number of devices, etc. I used the Euro style terminal strips below the layout top at all the accessory connections. The acc wiring goes through the table top to the terminal strip and then back to it's power source which is mostly a larger terminal strip. I used some MTH terminal blocks for some items here as well. I get the Euro style terminals that are 12 to a strip. They can easily be cut to any length you need. They have holes between the terminals for attachment using a small screw.

No non-derail boards currently in operation, decided I didn't really need them at this time. Will probably use the thermostat wire if I ever add these. I do have a few Atlas #6924 boards that I may add to certain switches when I expand my layout. I was also going to use an AIU, but I decided I liked having the switch controllers right at the switches so I haven't yet purchased an AIU. Another item that may get added with an expansion. Would be nice for routes and maybe other things, but I only have a 6'x16' layout right now. No real routes so to speak, just a couple of loops with spurs and sidings. No signals yet either, but I like the Atlas signal system and would like to add it someday in the expansion.

I really wanted to use #20-#22 stranded for all my switches, accessories and lighting, etc. Finding different number of conductors, non-shielded and reasonably priced in smaller quantities was difficult, so I settled on the thermostat wire from Home Depot, not my first choice, but works well, there is a good selection, it's readily available and Home Depot and Lowes are fairly close and I go there probably once a month or so anyway.

Susan's link above has wire size info, There are also several websites that will let you figure voltage drop and other calculations for different wire sizes and lengths.

I think wiring for DCS is a good idea. I also prefer it to bus wiring. Personal preference here I suppose, but it's just easier for me to keep track of with a pair of wires going to each track block and a terminal strip for each loop rather than feeding them from one large bus. I also have a switch for each loop so they can be powered separately. Probably not necessary, but it's there if you need it.  

Stranded not solid.

As mentioned, stranded wire not solid wire because the experts say DCS works better with stranded.

Because I run 15 amps to the track (two PH180s through TPC400, PSX-AC circuit protection set at 15 amps), my power wire is:

-TPC400 to MTH terminal blocks - #12

-MTH Terminal block to short track leads - #14

-Track leads to track - #16 (for easier soldering to track)

For most other applications I use thermostat #18 wire because its easy to find.

I strongly agree with rtr12.  You did not say what switch motors you use. Z1000 motors can get by with 22 gauge, but NJL motors need at least 18.

If you could find twisted, stranded wire, it would cost a fortune.  You can make your own using a variable speed hand drill.  Find a spot in the house where you can stretch out a long length of wire.  First, unspool a short length of the 2 wires and tie them together with a simple knot.  Fasten the knotted end to something that won't move, like a table leg or banister or door handle or your bench vise.  Then stretch out a length of the two wires as far as you can go and pull them taut.  Tie them together and clamp the knot into your drill.  (I place a cup hook into the chuck and tighten down on it.  That makes it easier to attach the knot.)  Then, with drill in hand, pull on the stretched out pair to make them fairly taut and start the drill on slow or medium speed, keeping tension on the wires.  (Keep the kids away from the drill in case the wire comes loose from it as you're twisting it, as it will whip around in the air for a few seconds.)  The wire pair will shrink in length as the wire is twisted.  Keep running the drill and watch the twist segments.   When they get really tight, time to stop.  Now, be careful as you release the wire from your drill.  It will try to untwist some, and it could fly about until it settles down.  It may also curl up on itself.  Straighten it out, and you have a twisted pair, in the gauge and color that you want.

If you are planning to use DCS, twisted pair wire is best to feed track power.  It keeps the RF signal strong and helps reduce interference from external sources.

Starting fresh consider purchasing 500' or  250' rolls readily available on line in 12 colors.  Much cheaper than HD retail type of small quanitity purchases.  Pennies per foot.  Any precut wire is premium price.

I use 12 colors in 4 sizes.

For twisting wire I just use a Vise grip to hold one un knotted end to any edge, walk across the basement then just stick the two un knotted ends in a chuck and let 'er spin.  I am running dozens of circuits up to 45' lengths.

I just wired a friends layout who had pre purchased  eight colors of 12 ga SOLID wire.  Not my first choice but it does not get all tangled up when you release it from the chuck.  Long lengths of twisted stranded wire is best when you have a helper hold the other end stretched out while you thread it through the cross members. 

When twisting long lengths I wrap several turns of tape every 8' or so b/4 releasing the two ends.  This step reduces crazy twisting and curling.

I also use 12 colors of electrical tape to further code wire runs.

The cup hook/knot idea sounds like a good idea,    Thinking maybe not with 12 ga solid.

IMO, Do not pull wire off a reel side ways. Pull it straight off like line from a fishing reel to avoid a major mess.

RJR posted:

I strongly agree with rtr12.  You did not say what switch motors you use. Z1000 motors can get by with 22 gauge, but NJL motors need at least 18.

I'm using the Atlas switch motors, as implied with using the anti-derail boards (Well, at least Atlas is the only ones that I know of that make such a board, and I thought they only worked with their switch motors.).

As for twisting my own, that's something I didn't think of.  Thanks for the info!

Also, does anyone know what size the wire that comes with the Atlas switches is?

You might want to visit my website for information on wiring and products available to make this part of layout construction a little easier. www.montanarailpower.com