Stranded or Solid?

[Jumijo]

Time to wire up the layout. I'm going with 14 guage wire - but should I use solid or stranded? Is one better than the other? If so, please explain why.

Solid or stranded? That's the question.

Jim

[IRONROOSTER]

This has been kicked around quite a bit in the model railroad forum. Bottom line is that the differences are too small to worry about in model railroading. Some people prefer stranded because it is more flexible and easier to bend while others like solid because there is only one wire to solder or attach to terminals. Use which ever one you prefer to work with.
Enjoy
Paul

[Buckeye Riveter]

QUOTE: Originally posted by IRONROOSTER

This has been kicked around quite a bit in the model railroad forum. Bottom line is that the differences are too small to worry about in model railroading. Some people prefer stranded because it is more flexible and easier to bend while others like solid because there is only one wire to solder or attach to terminals. Use which ever one you prefer to work with.
Enjoy
Paul

[#ditto]

I use both. Cheapest at the time of procurement is my guide.[:)]

[Jumijo]

Thanks, guys. No real difference between solid and stranded, huh?

Jim

[spankybird]

I also use both. If it is stranded, then I tin the ends so it becomes solid.

[Big_Boy_4005]

Only stranded for me , but I use all kinds of crimp style connectors, ends, and splices.

[Jumijo]

I do intend to crimp on connectors at the ends.

Jim

[lionelsoni]

It is often alleged that stranded wire has lower resistance because it defeats the skin effect.

The skin effect is a phenomenon which confines the current to the outer surface of a conductor. It increases with frequency and with conductivity. At 60 hertz in copper, the skin depth, the depth into the conductor at which the current decreases to 37 percent (1/e) is about 8.5 millimeters. When the skin depth becomes comparable to the wire radius, the effect on wire resistance becomes extremely small. The diameter of 12 AWG wire is only 2 millimeters, which would make any effect virtually impossible to measure, much less notice when running trains.

Ordinary stranded wire does little to reduce the skin effect in any case. There is a special kind of stranded wire, called litz wire, which is effective in reducing the skin effect. The litz-wire strands are insulated individually and woven together in a way that puts each strand near the surface and the center of the bundle at various places along the wire. The strands of ordinary wire are not insulated from each other and are not woven. So, even if there were a skin effect at the frequencies and wire sizes that we use, stranded wire would not help.

The only sensible consideration is convenience in working with the wire.

[Anonymous]

Stranded!
Far less likely to break and much easier to fasten effectively(solder or crimp). One reason stranded is used in appliances,machine tools and fixtures.

[laz 57]

I went with the 16 gauge stranded paired white lamp cord.
Got it at an Army Navy store.
300 feet for $20.00.
I use a magic marker on one side to decide which one is the hot lead.
laz57

[Dr. John]

I use 14 ga. stranded for bus wires, then solid wire of various gauges for feeder wire to track or accessories.

[lionelsoni]

George, feel the edges of your lamp cord. One should be smooth; the other should have an almost invisible ridge or ridges. That is the "identified conductor" and the one that is normally grounded. Even if your wiring is already in place, knowing this could be useful for identifying which wire is which at both ends for repairs, alterations, and additions.

[laz 57]

Thanks BOB, I didn't know this.
laz57

[eZAK]

According to code all paired conductors must be identified. i.e. lamp cord, romex, etc.

Stranded or solid?

Stranded for awg #16 or larger,

Solid for awg #18 or smaller.

Reasons are ease of working with and ease of termination!

If you still don't know buy a little (or visit a home construction site for scraps) and try each one out and see for yourself.

[jkerklo]

Either stranded or solid copper wire will serve well for wiring a train layout. Each, however, has benefits and disadvantages:

Stranded is easier to bend and route around. Solid is easier to poke through holes.

Solid is easier to form in a loop to go around a transformer post. Stranded should be "tinned" so it is solid before forming the loop. Wire should ALWAYS go around a post CLOCKWISE; otherwise, tightening the post will force the wire away from the post.

If you twist two or more solid wires together, they will stay. Stranded wires twisted together will come apart. Solder or a wire nut will help both. Twisting solid and stranded wires together usually doesn't hold and should be soldered.

A solid wire nicked during stripping will break. A stranded wire may lose a strand or so, but will not fail completely. Only use a stripper that has a formed hole! Never use one of those "one size fits all" types: they will nick the wire every time. Even check the hole to use. Strippers are different for stranded and solid wire. In general, use the next hole up for stranded. An automatic stripper will save a lot of time. To check for nicks, strip a half inch, then strip another half inch. Look for nicks where the first strip was made. Use the next hole size up if the wire is nicked or any strands are cut.

House wire is cheap. "Stranded" house wire has only a few strands, so is sort of a compromise between solid and stranded. Smallest size available is #14.

Use "hook up" wire otherwise. It has the smallest insulation. "Appliance" wire has thicker insulation, so wire bundles will be larger.

I use #10 solid, bare copper "grounding" wire for "track common/outside rail" run under the track areas. Short #16 wires are connected to the outside rail and soldered to the bare wire. A #10 or #8 wire is not overkill for "Track Common." It must carry the sum of the current for all engines and anything else connected to "track common."

I use #14 "house" stranded for my center rail bus wiring, with #16 stranded feeders to the rails.

Use as many different colors as you can find. A convention will help. I use "white" for all track common wiring, and different colors for various track sections. Helps to figure out what's going on later.

Enjoy your wiring.

John Kerklo
TCA 94-38455
www.Three-Rail.com

[eZAK]

Good advice John,

I would however add that back twisting (holding the wire in your left hand and tightly twisting the strands toward you with the right hand) the stranded wire for terminals and always using wire nuts on splices will eliminate the need for solder.

[Anonymous]

Bob Nelson's description of conductor identification on paired cords also applies for the secondary [low voltage output] cord on Lionel PowerHouse transformers. This knowledge is only useful if you cut the plugs off [as I do] and solder on spade lugs for connection to terminal strips used as distribution junctions or wired to TPCs, for paralleling,etc.
The ribbed or ridge "teltale" along one of the conductors in the PoHo cord's pair is the Common conductor. I use white code for the Common on my RR so I wrap a piece of white plastic tape around the shrink tube on the barrel of the soldered spade lug of the ribbed/Common conductor.

[FJ and G]

Solid is definitely better than stranded. Fact, that's what my house is wired with.

However, ensure that there will be no twisting motion involved as if you continually bend solid, it will break more quickly than stranded. The smaller gauge solid, like phone cable, a really the culprits in this respect.

So, it all depends on how you are going to use the wire.

I'm debating whether or not to go solid or stranded in rail-to-rail jumpers, where movement, due to heat/cold differentiation, would be slight.

Any opins on this are welcome.

[Anonymous]

David, I am just wondering if you could elaborate on your statement that, "Solid is definitely better than stranded." Seems lots of people feel it does not matter if one uses stranded or solid, but you definitely go with solid. Can you explain some of the reasons that solid is better? Thanks!

[FJ and G]

Reading and PA RR,


"It should be common-sense knowledge that liquids flow through large-diameter pipes easier than they do through small-diameter pipes (if you would like a practical illustration, try drinking a liquid through straws of different diameters)."

From: http://www.faqs.org/docs/electric/DC/DC_12.html

Other sites reviewed agree, as well as my neighbor, who is a telecommunications specialist w/SAIC, working for military. He helped me wire my house.

The #1 reason for buying stranded is FLEXIBILITY. If you're wire is going to be continually moved, then that's the way.

Some say that since stranded has more surface area, it should be able to allow more electrons to pass. However, the inner strands do not have as much current as the outermost section of the strands, and much of the stranded wire is just air or dead space, meaning that you need a thicker stranded wire to carry as much current as a thinner solid wire.

But whether you have 14 ga stranded or solid, the effect most likely will be so minor in model RR operations as to be meaningless.

If your layout is a large one, I'd recommend going with 12 gauge. Even some large HO layouts use 12 gauge for the bus wiring.

There are several other advantages to solid. For one, it is usually less expensive than stranded (Romex, for instance), b/c it is so widely used in households (in Virginia anyway).

It is easier to crimp (or pigtail) solid wire and standardized and inexpensive fasteners are made for connecting these solid wires (the multicolored plastic fasteners found in your outlet box).

[lionelsoni]

A stranded wire of a particular gauge has the same amount of copper as a solid wire of the same gauge. The bundle of strands is larger because of the open space between the strands. There is virtually no difference in the amount of current that flows in the inner strands as compared with the outer strands. The National Electric Code allows the two types to carry the same current. The two are electrically equivalent, whether for wiring houses or running trains.

While a smaller soda straw is harder to drink through than a larger one, the effect is not linear with soda straws as it is with wire. Two straws, each with half the cross-sectional area of a larger straw, will together let through less liquid than the larger straw at the same pressure. On the other hand, two copper wires with half the cross-sectional area (say, 13 AWG) will let through the same current as one larger wire (say, 10 AWG) at the same voltage.

[BR60103]

I suggest both. Stranded where the wire will be moved a lot, solid where it willl be fixed solidly in position. (On your house, the wire in the wall is solid because it should never be moved again. Lamp cords and the like are stranded.) Walkaround throttles and such should be hooked with stranded, but layout wire should be solid.

[Anonymous]

In the recent CTT article on installing DCS, stranded wire was recommended. Seems signals can't be transmitted correctly through solid core wire...or something like that. This resulted in the author having to rewire track power using stranded core to his entire layout to enable DCS to function properly. I was at the beginning of wiring my layout when I read this. Hoping someday to upgrade to DCS it made my choise of wire easy.

Bruce Webster

[Jumijo]

Since there doesn't seem to be any real concensus of which type of wire is better, I'm going to use stranded, with crimped connectors at the ends. My layout isn't very big. Two 8 x 4 foot tables arranged in an L configuration.

Thank you all for the great replies.

Jim

[Anonymous]

Hi Just started to do some posting and I would like to trow my two cents into this topic. First what size gauge wire would you consider using when one starts building a large,medium,or small layout? Secondly using say 1 3 4 8 engines and a normal amout of accessories? I am starting to build a L shape layout with measures 15x 15 and each leg is 4 feet wide. So far my two indivdual loop are fed with 18 gauge wire to their indivdual buss bar and then I am using telephone wire to each of their track connections. My switch's are fed by telephone wire too. Is it really important that you have to go with heavy gauge wire? felix

[Anonymous]

Telephone wire is much too small for track hookup. It could actually overheat and cause a fire. 18 gauge would be very minimal. You could get away with it running some trains but a double headed diesel with lighted passenger cars could overheat your buss. Do yourself and your family a favor. Install a minimal of 16 gauge wire and install a 10 amp in line fuse to the center rail of each track. If you insist on using the 18 gauge buss install a 6 amp fuse. Get rid of the telephone wire.

Dale Hz

[Anonymous]

Hi dale Thank you for your imput about the size of these engines that draw a lot of current. I just started to get into o guage after being into Ho gauge for some 30 yrs. I wi***here was some info about how much power that these engines, sets , cars with lights draw when some is about to purchase these items. I happen to buy a mth passenger starter set and a 1992 lionel GP-38 with some freight cars. I don't think that they draw that much power. Before I purchase anything more I would wish mth would send out some info about how much power these things draw. Again thank you for that info Felix

[Tom1947]

I use what ever is available. I perfer the stranded for accesorys and the solid for the track. The solid wire can be sodered much easier to the track.

[lionelsoni]

Once again: Select the wire size according to how much current the transformer can put out, not how much current the train can draw. When a fault, like a derailment, occurs the current can be up to whatever the transformer's circuit breaker trips at. If the wire can't handle it, you are liable to have a fire.

[Anonymous]

Lionelsoni is right on the money as usual. Even a modest 100 watt transformer can put out 8 amps at 12 volts. Postwar transformer breaker are very slow tripping and often do not work.You can fuse to protect the wire however,If you do that you dont have to worry about transformer output. Fuse a 16 gauge wire at 10 amp,a 14 gauge at 15 amp, and a 12 gauge at 20 amps. Some 18 gauge wire can theorectically carry 10 amps,depending on the insulation but I would fuse it at 6 or 8 amps at the most. Fuses offer cheap insurance. Unlike mechanical breakers they always blow. Telephone wire is usually 24 gauge maybe OK for a lightbulb to a block signal but thats about it. If you want good cheap buss wire buy 16 gauge extension cords at Wallmart,15 feet extensions cost around a dollar or less.

Dale Hz