14 AWG stranded wire vs 14 Gauge wire vs 14 GA wire

The main difference between stranded 'speaker' wire and stranded 'general purpose' wire is the speaker wire generally has thicker, softer, insulation, and there are more and thinner wire strands. Because the strands are thinner, they can be twisted down into what appears to be a smaller bundle than the electrical wire.

But the electrical cross-section of the more numerous, and thinner, strands in 14GA speaker wire is the same as the smaller number of thicker strands in the 14GA general purpose wire. So electrically they are the same. But you may notice the price of 'speaker wire' is a bit higher.

Just looking at #14 wire in the handbook I find there are 23 different wires sold as #14. The ones I am most fimilar with are solid #14 which is 0.0641" in diameter and has a circular area in inches of 4109 mils. #14 wire with Class B stranding is known as 7/22, which means is has 7 strands of #22 wire.  #22 wire is 0.0253" in diameter. #14 class B stranded wire has a circular area of 4480.7 mils.  #14 wire with class C stranding is known as 19/27, which means it has 19 strands of # 27 wire. #27 wire is  0.0142" in diameter. #14 class C stranded wire has a circular area of 3830.4 mils.  #14 wire with class D stranding is known as 37/30, which means it has 37 strands of #30 wire. #30 wire is 0.0100" in diameter.  #14 class D stranded wire has a circular area of 3700 mils. And it goes on. 

Somerimes different applications need different stranding. For building model trains it is just a personal preference of how stiff of a wire you want to work with.   You can see that there is very little difference in the circular area, so all the wires have approximately the current carrying capacity and resistance. There are cases where some foreign made wires do skimp of the copper. If you feel that the wire you got is under size just strip back some insulation, spread the strands so you can count them,  and measure one strand with a micrometer.  It should match one of the stranding combinations above. 

AWG means American Wire Gage. 

A lot of the coding has to do with type of insulation and use.   TW, THW, THWN, THHN are common construction use codes on single strand wire.  Example:  Damp location, Direct burial, Higher heat rating, etc.  You also might note that 14 gauge solid is a slightly smaller diameter than 14 gauge stranded.  Also note that in most cases you are looking for Copper or Cu.  There is Aluminum wire and different variations of Aluminum, example: copper clad aluminum, and you also may find Tin clad copper.    

Whether it makes any difference or not to us, where we supply low currents to our layouts, the currents travel on the outside of the wire. The copper in the middle of wire strand caries less current than the outside edges. So if you use stranded wire, in theory you can carry more current than a solid single wire of the same cross sectional area of copper.

When in high school some 50+ years ago I saw a piece of the transmission wire from Hoover Dam. The transmission system carried power from the dam to Los Angeles. It was made up of solid interlocking copper bars arrange in a circle so as to form a tube. This gave them maximum current transmission capabilities and minimum weight, important when stringing wire from tower to tower.

The point for this post? Stranded wire of the same cross sectional area carries more current than a single strand wire. It will be larger in diameter than a insulated single strand wire as well because of the tiny air gaps between the individual strands. Does it all make any difference to us model railroaders?...Probably not because of our low current level. But it is interesting to know, it seems to me.

LDBennett

The main difference between stranded 'speaker' wire and stranded 'general purpose' wire is the speaker wire generally has thicker, softer, insulation, and there are more and thinner wire strands. Because the strands are thinner, they can be twisted down into what appears to be a smaller bundle than the electrical wire.

I've used 16 gauge lamp cord for my speakers forever.  I've never had a problem.

Whether it makes any difference or not to us, where we supply low currents to our layouts, the currents travel on the outside of the wire. The copper in the middle of wire strand caries less current than the outside edges. So if you use stranded wire, in theory you can carry more current than a solid single wire of the same cross sectional area of copper.

This post refers to something called the "skin effect". The skin effect is proportional to the frequency of the alternating current. At 60 hertz (normal USA house current) the skin effect in negligible. Even if it was significant, standard stranded wire would do nothing to counter it. There is special wire, called "Litz wire" that has each strand insulated to counter the skin effect. The strands are also woven in specific patterns.

I am certain there are folks with much deeper knowledge who can expand on what I've written.

The wire size will be fine and you have the benefit of it being a paired wire which simplifies pulling the wire. It should also have covering that is more flexible than those with higher fire code standards.

It will work just fine and provide a sufficient safety factor. David and Mike CT have provided enough detail.

Hey, I'm no expert in the electrical differences and or benefits of any wire but here's what I learned while buying the wire to power my layout. I choose speaker wire, the reason really doesn't matter for the purposes of my post since I'm only addressing the OP photo/question about size difference and pliability.

First, not all 14AWG wire is the same in that there actually is something called "true 14 AWG" wire versus what I'll call "nomimal 14 AWG" wire. Yes, you guessed it, while some wire may be labeled and sold as 14 AWG the actual copper core may not be a full 14 gauge and therefore narrower or thinner as in the photo. Think of it like the lumber we buy to build our benchwork. A 2"x4" is not actually 2"x4" and therefore it is called nominal lumber versus true stock.

Next, not all stranded wire contains the same number of strands of copper wire inside the casing. This is true for both "true" gauge and "nominal".  What's the difference? As I understand it and it was explained to me, the more strands the better the conductivity. Is this true? I don't know but that how an expert I know explained it to me. What role does the number of strands play besides conductivity in what we do? Well, I can tell you that the speaker wire I initially purchased from HD was true 14AWG but it contained only 7 strands of copper wire inside while the "true 14 AWG" theater wire I purchased afterwards contains 105 strands. The theater is much more pliable than the 7 stranded wire.

So the moral of the story is, not all14AWG stranded wire is the same.

I hope this helps.

Mike

My smallish (7x9) layout is wired in the MTH recommended STAR configuration. It is a single block with four feeding points on the track. Each run is two automotive wires twisted together and terminated at a common point on a terminal board. The results is the MTH DCS signal strength is virtually 10 around the whole of the layout. The track (unfortunately) is MTH RealTrax and there are NO soldered track sections interconnections. I avoided using speaker wire and simply twisted a pair of 16 gauge automotive wires for the length of the run (easy to do with a bench vise to hold the ends of the two wires and an electric drill at the other end, run until the desired amount of twist appears). This makes the wiring much neater under the layout if you plan support points along the wire paths. If you expect many more than three or four engines running on any one block at a time you may want to increase the wire gauge to 14 or even 12 gauge (??). Automotive wire as you might get at NAPA is truly the gauge marked on the spool, in my experience. Speaker wire, who knows?

LDBennett

First, not all 14AWG wire is the same in that there actually is something called "true 14 AWG" wire versus what I'll call "nomimal 14 AWG" wire. Yes, you guessed it, while some wire may be labeled and sold as 14 AWG the actual copper core may not be a full 14 gauge and therefore narrower or thinner as in the photo.

Never heard about this. Is there any place I can read about it?

Next, not all stranded wire contains the same number of strands of copper wire inside the casing. This is true for both "true" gauge and "nominal".  What's the difference? As I understand it and it was explained to me, the more strands the better the conductivity. Is this true?

As far as I know:
 The more strands, the more flexible and expensive the wire will be. The type of insulation also has an impact on flexibility (at least for the wire sizes I use) 
The number of strands as no impact on conductivity. See my comment above about skin effect and Litz wire.

The real test would be to measure the resistance. Not really practical for most though. 14 AWG should measure 2.5 ohms per 1000 feet. Pretty small for even a good digital ohmmeter to get right. 100 feet would be .25 ohms but you would need a Wheatstone bridge. Likely not many here have one of those.

Like CW I have never heard of true AWG. Is that like "music power" they used to rate audio amps in the old days?

Pete

The real test would be to measure the resistance. Not really practical for most though. 14 AWG should measure 2.5 ohms per 1000 feet. Pretty small for even a good digital ohmmeter to get right. 100 feet would be .25 ohms but you would need a Wheatstone bridge. Likely not many here have one of those.

I have a Leeds & Northrup Type "S" meter that is based on a Wheatstone bridge. According to the material I've read, one of the uses was to measure the resistance of a shorted line to determine how far away the short was occurring. Imagine that!

Here is one for sale on Ebay: Leeds & Northrup Type "S" meter

We used to use a time domain reflectometer to determine a wire's length but it wouldn't tell you what gauge the wire was. 

Pete

The easy way to measure the resistance is using power.  If you have 100 feet of that wire, run 10A through it and measure the voltage drop.  10A through 100 feet of #14 would be about 2.5 volts of drop.  That's for one way, for a 100 foot pair, it's 5V, that's 200 feet of wire.

true, there are different wire gauge standards (SWG, BWB, AWG), but American Wire Gauge (AWG) is defined by the National Bureau of Standards so i find it hard to believe there is a "true" AWG, "nominal" AWG or any other acceptable non-standard.  AWG is defined by the cross sectional area of the conductor or combined conductors as a logarithmic scale, so as with a 3dB change in audio volume, a difference of 3 in wire gauge doubles of halves the current carrying capacity (ie: 11G wire has twice the capacity of 14G wire which has twice the capacity of 17G wire).

a number of things may make similar American Wire Gauges appear different as in the number of conductors or thickness of insulation, but there should be no difference in current handling capacity.

cheers...gary

I am totally out of my league here but I recently took a layout apart and took the 100 pounds of insulated stranded wire to to a scrap dealer and was surprised that insulated solid copper wire (like Romex) was worth  $1.00 per pound but stranded insulated copper wire only bought 50 cents a pound.  When I asked about the disparity, I was informed that there was less wire content in the stranded.  I did not know how to argue so I just took what they gave me and went back home.

C W Burfle posted:

Whether it makes any difference or not to us, where we supply low currents to our layouts, the currents travel on the outside of the wire. The copper in the middle of wire strand caries less current than the outside edges. So if you use stranded wire, in theory you can carry more current than a solid single wire of the same cross sectional area of copper.

This post refers to something called the "skin effect". The skin effect is proportional to the frequency of the alternating current. At 60 hertz (normal USA house current) the skin effect in negligible. Even if it was significant, standard stranded wire would do nothing to counter it. There is special wire, called "Litz wire" that has each strand insulated to counter the skin effect. The strands are also woven in specific patterns.

I am certain there are folks with much deeper knowledge who can expand on what I've written.

Yes you pretty much have it all said on skin effect. The current in the wire tends to go to the outside circumference of the cross section of the wire, minimizing the number of field lines encircling the current producing the field.

I worked with a lot of Litz wire in grad school winding 455 KHz IF transformers for an RDF receiver. One thing is that while skin effect is negligible at 60 Hz, it's also true that the benefits of Litz wire are negligible higher than a frequency of about 1 MHz. By the way, I stripped the enamel off the 40 or so hairlike strands of Litz wire by heating the wire end red hot with a Bunsen burner and then dipping it in alcohol. The enamel just popped off. Might work for any enamel wire, but I have never tried it for solid enamel covered wire. The alcohol catches fire frequently, but is extinguished easily by dropping a lid on the alcohol.

Memories

As to the original post, again keep in mind that a lot of the "audio" wire on the Internet is actually copper clad aluminum. In that case, AWG 14 is approximately AWG16 in terms of current carrying capacity per a desired minimum voltage drop for a specified length of wire. IE, it's more resistive. Also keep in mind that the recommended AWG in wire tables for 100 foot runs of house wire do not apply to low voltage wiring. That is because an allowable voltage drop of say 5 VAC for a 120 VAC circuit, while acceptable in house wiring is way too much for a low voltage, 18 VAC, circuit. So GRJ's method of measuring the voltage drop with the current you are intending to run thru the wire is preferred when sizing your layout wire.

Just a footnote--

As yours is a DCS installation, you may be powering it with a Z-4000.  If so, and you expect high current draws like 10A (such as superimposed TMCC for a older twin Pulmor loco), you might consider that your source will have an adverse form factor, which might be 1.35 or so.  This means that the heating in your wiring will be greater by this factor; from this you can recalculate your expected voltage drops.  This increased heating would indicate replacing #14 wire with #11 wire, thus #12 or #10 wire could be a better choice.

I had a chance to make test readings on a large club layout, which had its bank of TIU's about 100 feet (as the four #16 wire pairs went) from two Z-4000's set at 18v.  The summer layout temperatures were about 40-50C (~104F).  A single unit TMCC loco as above stalled with a train of one passenger car, at the approximate most remote point about 130 feet plus some feet (10?) of Real Track.

My comments are based on this, plus some research on the sparse reports from the early 90's web.  One report discussed the form factor that a 5-tooth "comb" (variable pulse width in a half-cycle wave) would produce in varying the effective voltage of a constant sine wave input.  I was also informed that the Z4 contained a fixed 28v output transformer for the handle outputs.  (The patent omits many details, but cites the "comb".)

I realize I will have stepped on the toes of some who may believe that a waveform, whose envelope is a pure sine wave, is always also a pure sine wave.  Unfortunately, this is not true.  Sorry

--Frank

Another note:  It takes four wire numbers, not 3 as mentioned above, to double the current capacity of a wire (when heating controls, as is the usual case with wires #10 to #14).  This is because the surface area of the wire does not increase at the same rate as the cross-section area increases.  The heat dissipation is limited by the surface area.  This rule of 4x (#16>#12, for example) is not as close if the insulation thickness changes (such as #22 compared to #14, due to the difference in usual voltage classes, or if a high temperature wire is used).  The 4-step doubling factors are x 1.19; 1.41; 1.68; 2.00.  Or, in the commonly available wire sizes, 1.41; 2.00; and going down, 0.71 and 0.50 (thus if 10A for #16, then 7A for #18 and 5A for #20--with 60C insulation).  With 10A current limiting and high temperature wire UL has permitted #18 in affixed output wiring of certain Toy Transformers

F Maguire posted:

 

I realize I will have stepped on the toes of some who may believe that a waveform, whose envelope is a pure sine wave, is always also a pure sine wave.  Unfortunately, this is not true.  Sorry

--Frank

 

Great comment. There are many recent issues with increased heating due to switching supply loads and non sine wave forms in power distribution systems. This has become a major issue with large office buildings forcing some serious rethinking on wire size per current load.

F Maguire posted:

Another note:  It takes four wire numbers, not 3 as mentioned above, ...

AWG 11Ga (defined) -- 0.0907" dia
π × (0.0907 ÷ 2)² = 0.006461 in²

AWG 14Ga (defined) -- 0.0641" dia
π × (0.0641 ÷ 2)² = 0.003227 in²

2 × 0.003227 in² = 0.006454 in² ≈ 0.006461 in²

there is theoretical and then there is practical.
nobody makes 11 Ga wire, so of course 10 Ga is recommended.

cheers...gary

Here's something on heating from harmonic content in power systems...

http://www.eaton.com/ecm/idcpl...amp;dDocName=WP10-03

Harmonics would be at a higher frequency, and thus experience more impedance.  More impedance, more heating and energy dissipated.  I've never considered that for low frequency power transmission, interesting...

I listened to EZMIKE and bought the best 14 AWG stranded wire I could find after reading about wire testing. I bought my wire (which just arrived 10 minutes ago . . . .  YIPPEE, from Monoprice. On the New Munoz Lines, there will be no compromise. Freight or passenger, it will all get there on time. Right, Mike?

PLCProf posted:

gunrunnerjohn posted:

Harmonics would be at a higher frequency, and thus experience more impedance.  More impedance, more heating and energy dissipated.  I've never considered that for low frequency power transmission, interesting...

 

There are a zillion effects that occur when frequencies get high in relation to the dimensions of the conductor. Despite our best efforts to make an issue out of them, they are ALL negligible in toy train wiring!

Probably so, but interesting never the less. Again the JRG method, wire the AWG run,  run the current you think you need, measure the voltage drop and if it is satisfactory, drive a nail in it...

Thanks all for the tips.  Here's a photo of what I bought at Lowes's--finally found the reels.

Guess I should twist the red and black with vise and electric drill and get on with it. 

(I sent the 2 conductor 14 GA "speaker" wire back to Amazon as several people gave it a 1 or 2 star rating saying it was really 16 or 18 gauge and lousy wire.)

BTW, I'm using RealTrax and I like it.  Connections are very tight, the switches are very reliable and as a beginner modeler I find the non-derailing

turnout feature beneficial.

Guess I should twist the red and black with vise and electric drill and get on with it. 

Why?
I think the wire would be much easier to work with when it is not twisted.

Does DCS call for the wires to be twisted?

DGJONES posted:

I am totally out of my league here but I recently took a layout apart and took the 100 pounds of insulated stranded wire to to a scrap dealer and was surprised that insulated solid copper wire (like Romex) was worth  $1.00 per pound but stranded insulated copper wire only bought 50 cents a pound.  When I asked about the disparity, I was informed that there was less wire content in the stranded.  I did not know how to argue so I just took what they gave me and went back home.

That sounds suspicious for a couple of reasons. First, less copper should equal less weight, which should cover any price difference, and second, a 50% price difference should mean a similar reduction in the amount of copper, which should be easy to see the difference with the naked eye. Are you sure they weren't talking about multi-conductor wire (like telephone wire), which would have a much higher ratio of insulation material to copper for the same weight?

Bill in FtL

CW BURFLE asked:

Why twist automotive wires?

DCS wants feed points (Lock-ons) fed in a star pattern from the transformer. That means paris of wire to each lock-on. When twisted together it takes half the time to string wire laying on your back and crawling around under the train table. Also there is a electrical benefit.

Twisted pair wires act to cancel out any spurious signals from the track or induced along the travel path. They are less susceptible to spurious  interference signals.

I also find it much neater and much easier to trace wires under the layout. I have used this technique for years when I would rewire vintage motorcycles by providing every circuit with its own return path in a twisted pair, augmenting the frame ground path. 

LDBennett

Some replies... sorry to be a bit late getting back, it's been a hard week.

@Overland Flyer-- Gary, thanks for the area data.  I don't know about #11, but curiously #9 is used in a lot of control systems which run some distance outside.  Usually buried, in a variety of cabled configurations, or singly in conduit... I never learned exactly why #9, but just followed what I had observed.  Actually, you can get anything you want, almost, if you buy enough of it.  I needed a #9 but with a low-cap insulation, which was a special order... I've forgotten if the minimum was 7000 feet or 11,000, but I needed 17,000 feet.

@PLCProf-- Basically, harmonics are dealt with mathematically by decomposing the unusual wave form into its Fourier series, he being a French math expert.  It is a series of sine and cosine waves, and it has been proven that any waveform can be so represented.  Actually doing that is another matter, and having been required to do some of the simpler cases in the days before computers and canned programs, I can say there is little point in learning how these days.  But square waves generally as a practical matter have their corners rounded by the odd harmonics-- 3rd, 5th, 7th and so on, of increasing frequencies and decreasing amplitude.  So the 3rd is most important, and the total added loss is pegged at being enough to cancel the advantage of reduced neutral size in multi-phase circuits feeding fluorescent lights.  Typically such things are determined by using two watt-meters, at each end of the circuit conductors, which measure energy and thus heat.  Thus, I suppose, form factors as an expression of the added heating effect.  This, despite the effect on all (including model train) motors being one of voltage reduction, which is quite serious. 

So, in my example case, I measured voltage drop, at the time, and inferred a form factor around 1/3 added, from that.  Much later, I found on the internet an example of a pulse width modified device which produced a reduced effective voltage, using a process similar to the Z4000.  Possibly this was a dimmer design; it was about 1992 with a form factor stated to be about 1.35 (35 percent).  This was similar to my voltage drop problem.  A first problem with such a system is that the fundamental of the output is not 60 cycles, but n x 60, n being the number of square-edged comb teeth in a cycle.  This is thus the common 400-cycle system problem on steroids.

! wanted to add a bit about the DCS signal and twisted wiring, and how the form factor problem was dealt with in the passing years, but it is again late.  Later.  --Frank

F Maguire posted:

Some replies... sorry to be a bit late getting back, it's been a hard week.

@Overland Flyer-- Gary, thanks for the area data.  I don't know about #11, but curiously #9 is used in a lot of control systems which run some distance outside.  Usually buried, in a variety of cabled configurations, or singly in conduit... I never learned exactly why #9, but just followed what I had observed.  Actually, you can get anything you want, almost, if you buy enough of it.  I needed a #9 but with a low-cap insulation, which was a special order... I've forgotten if the minimum was 7000 feet or 11,000, but I needed 17,000 feet. ...

you're right, i should have said "not readily available" in odd (literally) sizes.  it would make sense that if the quantity was large enough as in your example, a small change in gauge could translate into a large $$ savings even considering the cost of a special run.

The only real difference in 14 AWG wire is the insulation type or being solid or stranded. 14 AWG is just that! If somebody is selling wire less then the diameter for 14 AWG wire they should be reported to the NEC or National Electric Code.

I have never heard of nominal wire or what ever. Speaker wire labeling is just another way to get more money out of the buyer.

Lee Fritz

Well, much of the "speaker wire" sold on eBay is really copper coated aluminum wire, and will not be as good as real 100% copper wire.

My understanding of speaker wiring is that an 8-ohm speaker, say, is actually wound as 7-ohms.  Then the wiring from the amplifier to speaker out and back would be sized to make up the missing 1-ohm.  This of course depends on how far the speakers are from the amplifier.

In this case, the internal resistance of the amplifier, as a signal source, would be 8-ohms in each channel, and you would connect "8=ohm" speakers.  But what is at work here is that the maximum power output from a source occurs when the resistance of the external circuit is exactly the same as the source resistance.  This is a proven mathematical relationship.  So you choose a wire size that gives a half-ohm each way.  In a resistive circuit, this would also maximize the current, and it is the current through the speaker coil which drives the sound output.  Bigger speaker wire is not necessarily bigger sound.

Doubtless there is some inductive impedance effect as well.  As long as this is relatively rather smaller than the resistive effect, the result will be a phase shift but little effect on output.  (The ears deal well with phase shift, even if different at the two speakers.)

This maximum power output relationship can be used to investigate situations where external thermal breakers are used to protect circuits use on layouts.  To shorten a lot of explanation, just consider most such devices were developed to protect wire large enough that the voltage drop at the end of such circuits would not exceed 5%.  With smaller or less conductive wire, there is risk of not drawing enough current to have breakers open with sufficient speed.  Another risk with speaker wire is that its insulation may not alway be rated for 60-degree Centigrade operation, another assumption with these breakers.

--Frank

At one time I was TOLD by an electrical engineer, also my superior, that solid wire delivered more power than stranded over distance and my school was wrong. I never asked if that was voltage or amperage, measured cross section equal, or written rating, I just followed orders then unfortunately.

 On the other side of the coin, stranded wire normally gives a larger contact surface at connections by flattening out. To stand the coin on edge, more pressure yeilds a better connection , it's a direct relation, more pressure = less resistance, and a fat wire can withstand more pressure.

Being a fan of overkill and lacking my own lab, for power I just go big, and sleep well...or better anyhow. Fat wire just doesn't glow red with heat as easy, plain and simple.

Lionel's use of solid wire in sets? I figure it was for ease of use with the lock on sprung clip connectors (50 years of trains and I can never remember the real name for those clips, lol, even an hour after reading pennytrains post with reference to it I only remember it begins with an F and sounds German to me.......and that's progress, lol.)

I have read that in use on sound systems, that stranded was prefered to maintain the frequencies more accurately and too large a wire can cause a big loss in delivering highs. There are audiophile guidelines based on type, length, wattage, and frequencies. Check the strand count on audiophile wire, it's usually a huge count. I NEED 12 gauge on my sound equipment, but it's overkill on the layout..

All things considered, on a command system, I'd use slightly oversized stranded for signal retention unless the mfg. specified otherwise.

This is a very interesting thread; Time domain reflectometers, Litz wire, harmonics...  Wait, is this model trains or radio school? lol   Heck, I've been using twisted pairs to feed my layouts for 20+ year but never considered it for anything except convenience.  

I am going to throw my experience in here.  First, a few rules of thumb:
  Every main line loop as at least 2 power feeds (most have 3 or more).
  I never rely on a switch or crossing to carry track power.
  All feed pairs are twisted for convenience.

I use a decent quality 14 gauge wire (something with a decent number of strands) from all power sources (transformers, power bricks, etc) to what I term distribution (a TIU or terminal block).

From distribution, I use the same sort of decent 16 gauge wire to feed the tracks.  Remember the rule of thumb is 2 feeds minimum for each mainline loop.  Why only 16 gauge?  Well, another rule of thumb I learned years ago is 2 - 16 gauge wires can carry the equivalent of what 1 - 14 gauge wire can.  2 - 14's can carry what a 12 gauge wire can and so on.  So by using at least 2 16 gauge feeders, I spread the distribution without having to use the size of a 14 gauge wire.  Plus it's cheaper.  I also feed power every 8' of track or so.  With this in mind, even a 4x8 would have 3 feeds.

When I build a layout I test it in 2 ways.  First I run a conventional engine around to check how well it maintains speed.  Then I add a set of passenger cars with incandescent lights and repeat the test.  If the speed is good, you know you have the feed placement and number of feeds correct.
The second test is a DCS signal test.

Last year I built a new holiday display using my madness.  My DCS signal was no less than 10 all the way around and my old 671rr pulling a load of MTH passenger cars ran as consistent as something can without speed control. 

This is how I do it.  It works.  But there would be nothing wrong with using larger wire around an entire layout.  I wouldn't use solid wire for 2 reasons: it's a bear to work with compared to flexible stranded wire and I am not sure how TMCC/Legacy or DCS would work with it (considering the discussions regarding higher frequency).

One last thing I will say is if I were lucky enough to be able to build a large layout, I would consider using 12 gauge wire for long distribution runs (~50').  Not for any other reason than 12 gauge wire has less loss than 14 gauge for the longer runs.

I hope my $.02 helps and doesn't confuse the conversation.

Tony

DGJONES posted:

I am totally out of my league here but I recently took a layout apart and took the 100 pounds of insulated stranded wire to to a scrap dealer and was surprised that insulated solid copper wire (like Romex) was worth  $1.00 per pound but stranded insulated copper wire only bought 50 cents a pound.  When I asked about the disparity, I was informed that there was less wire content in the stranded.  I did not know how to argue so I just took what they gave me and went back home.

From Wiki...

"The AWG tables are for a single, solid, round conductor. The AWG of a stranded wire is determined by the cross-sectional area of the equivalent solid conductor. Because there are also small gaps between the strands, a stranded wire will always have a slightly larger overall diameter than a solid wire with the same AWG."

But then of course, the amp/distance rating depends also on the material. Copper, copper clad aluminum, etc. And AWG tables only deal with wire cross section, not material...although there may be tables for different wire materials. I think there are tables for aluminum wire, but copper clad I haven't seen. Also there is copper clad aluminum in different percentages like 10% cu and 15% cu over aluminum.

"Be specific and you'll be terrific..."

I'm guessing the tables for copper clad aluminum would basically be the aluminum tables.  There is very little copper in one of those wires.

DGJONES posted:

I am totally out of my league here but I recently took a layout apart and took the 100 pounds of insulated stranded wire to to a scrap dealer and was surprised that insulated solid copper wire (like Romex) was worth  $1.00 per pound but stranded insulated copper wire only bought 50 cents a pound.  When I asked about the disparity, I was informed that there was less wire content in the stranded.  I did not know how to argue so I just took what they gave me and went back home.

I have sold scrap copper and wire for several years.  The price you get is dependent on the company you are selling to and what their market wants.   I have seen them pay $1.00 per pound for used, mangled, absolutely worthless circuit boards because they were getting $7.00/lb on a contract from China. 

We have only two yards left locally and both owned by a very large metals corp with about 50 sites in the U.S.   If you take them 16 gauge or lower stranded wire that has the insulation removed you will get the highest price.  If you take them solid 99% copper bars or high end 99% solid copper computer heat sinks you will get 1/2 of the price of the 16 gauge stranded wire price.   You can polish the 99% copper, cut it in half for them or what ever to show them it is solid and pure, but it doesn't affect the price they will pay.  It primarily has to do with what their current demands and contracts are.  On smaller gauge wire and wire with insulation still on it, the price drops very dramatically.  Computer cables are almost not worth driving to the salvage yard to sell.  Their price doubles on insulated power cords 18 gauge and heavier if you want to spend the time and effort to cut the ends off of it.

As for the layout, I used 14 gauge solid wire around most of the layout distance.  I tapped into the track with a 16 gauge stranded pigtail and soldered to the bottom of the tracks.  It just happened to be what I had the most variety of in colors and with the solid wire I could pull it tight and mechanically anchor it at each end like a guitar string.  That kept it from sagging down. 

The interesting phenom in the whole transformer/speaker wire size discussion is looking at the smallest link in the whole connection.  The wire size inside the big stereo amp and the driver transistors is actually a very small gauge.  I've never looked inside the modern transformers and bricks, but I wonder what size wire is used in the power distribution getting out to the outside user interface terminals.