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Best Wire Sizes for LEDs and Repowering Jobs

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  • Member since
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Posted by cedarwoodron on Wednesday, January 23, 2013 4:14 PM
Now that I am comfortable working with LEDs in engines and structures, doing the work in a more "elegant way" that doesn't cause spacing problems (under diesel hoods) or present issues with appearance (wires visible in structure lighting) is now a major concern, so looking for the right wire size is important. My quick solution for the ribbon cable wires is to paint them with a red or black sharpie marker. One of my co-workers told me he has a bunch of ribbon cable he can give me in varying wire sizes, so I guess I beat the need to buy online- for a while! Cedarwoodron
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Posted by mlehman on Tuesday, January 22, 2013 10:32 PM

rrinker

 For then connecting the building back to the control panel or power supply - I wouldn;t want to run strings of magnet wire all over under my layout, it's far too fragile for that. This is where the printer cables come in, or if you need longer, get some telephone wire. Multi conductor and color coded.

             --Randy

Yep, I use something heavier and able to hold up to some minor abuse to run from the structure to the power connection. I usually use a puddle of CA to tack the termination of the magnet wire or other light wire in place where it's soldered to the power lead to act as a strain relief.

In some cases, I go from magnet wire to there, then use a short section of insulated stranded decoder wire for the trip through the scenery, then solder the power leads to that. If I'm using 22 gauge, it's sometimes a little stiff and this lets the structure settle down on the surface without pushback from the springy power lead.

The question was asked about why people use heavier than 32 gauge wire and what the capacity is of various wire sizes so it's sufficient for LEDs. And there are reasons to check that on very long runs of the smaller wire sizes or if a truly large number of LEDs was installed in a single structure. In general, however light the wire gauge you use with LEDs, it will be sufficiently heavy for use inside a structure with several dozen LEDs.

Ideally, you have the exact size you need and don't waste excess material by using larger than necessary gauges of wire. However, a lot of folks just want to know what'll work based on what they have on hand, as the OP found once he checked for that old computer. Voila! problem solved. And the smaller wire gauges with flexy insulation ordered through hobby vendors tend to be a bit on the pricey side unless one does some digging for a good price. Sometimes that roll of 22 gauge RS wire works just fine, even though it's overkill in terms of its capacity.

But it's true that it's worth seeking out the right wire for a good price if you're going to do a lot of wiring. Standardization is a good thing when you're doing something over and over like when installing LEDs.

Mike Lehman

Urbana, IL

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Posted by Soo Line fan on Tuesday, January 22, 2013 9:20 PM

Wiring is sized to prevent excessive voltage drop. Home wiring is typically between 3-5% allowable drop.

We keep automotive to much tighter specs. High current will be 1-2% voltage drop and ECM and low current circuits will be as low as 0.2 to 0.5% voltage drop per wire.

Here is a good online calculator: http://www.calculator.net/voltage-drop-calculator.html

Jim

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Posted by rrinker on Tuesday, January 22, 2013 8:07 PM

Yes, just google wire resistence, you cna get the values for all sizes of wire, in ohms per foot. Remember s circuit has 2 wires, otu and back, so if the LED is 10 feet away fromt he power supply, it's 20 feet of wire.

 And then use the current being drawn - a typical LED with the proper resistor is only 10-20ma, .010 amp-.020 amp.  Using something like 24-26 phone wire, you cna run a long way and not have any noticeable drop in the voltage with such a low current flowing through it.

                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by pirate on Tuesday, January 22, 2013 7:22 PM

When wiring decoders and speakers, Soundtraxx says to use 28 AWG wire.  I'm curious if there are any EE's (electrical engineers) out there who can provide the proper wire requirements in relation to amperage, resistance, etc? Obviously, not just for LED's.

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Posted by rrinker on Tuesday, January 22, 2013 5:03 PM

 Well, there's two things - wiring multiple LEDs within the structure - really small wire like magnet wire may indeed be good there. Ir just string two pieces of thicker wire like rails nad solder the LEDs to that.

 For then connecting the building back to the control panel or power supply - I wouldn;t want to run strings of magnet wire all over under my layout, it's far too fragile for that. This is where the printer cables come in, or if you need longer, get some telephone wire. Multi conductor and color coded.

             --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by cedarwoodron on Tuesday, January 22, 2013 2:35 PM
Thanks guys for your assistance. After I wrote the OP, I remembered I had an old PC tower in th garage attic. I took it down and found three ribbon cables ( gray type ) I was able to "harvest". Two of them appear to be smaller than 26 awg and one seems smaller than 30 awg. The on-off mini push button wiring yielded what looks like 26 awg in five colors, so I think I made a good scavenger's start, about five+ locomotive rewiring jobs' worth of material for free. Frugal is good these days! The gray ribbon cable I can touch with a permanent marker of red or black to "color code" what I cut off. Cedarwoodron
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Posted by BroadwayLion on Tuesday, January 22, 2013 2:26 PM

LION uses copper clad steel wire for his bus wires. Here they are in the station that I am building.

You find this material in a welder's shop and is cheaper than dirt. It is a little difficult to work with because it is so springy, but as you can see here, I made a basket weave between the station pillars, and it stayed in place perfectly.

If you buy this stuff, you MUST CONTROL THE SPOOL and the END OF THE WIRE. If you let go of either one it will spring right off of the spool. The welding machine that it is intended for will feed the wire automatically. I measure off a piece, and holding on to the spool and the spool end of the wire when I cut it. I then lock it into one of the holes in the spool side.

ROAR

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Here there be cats.                                LIONS with CAMERAS

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Posted by tstage on Tuesday, January 22, 2013 1:14 PM

30-32 AWG hookup wire is usually quite sufficient - unless you have an incredibly tight situation.  Just make sure you get stranded wire (vs. solid) so the wire is flexible and won't fatigue (break) when you move it around.

Tom

https://tstage9.wixsite.com/nyc-modeling

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Posted by richg1998 on Tuesday, January 22, 2013 1:02 PM

There is no Best size, only what works Best for you.

I have used #44 magnet wire for LED's. It is possible to knick the wire when using a razor blade or Xacto knife and bending the wire can cause the wire to fracture as you install it. A blob of hot solder will help remove the insulation.

I have used wire wrap wire but it requires a special stripper which I have as I did a lot of wire wrap work years ago.

For decoder installs and motor wiring, #30 wire, I use a wire stripper that does #22 to #30. Another stripper that does #10 to #22. No lap dances.

Some old times like to use their teeth if they still have any or their finger nails. Ego comes into this. lol

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by DigitalGriffin on Tuesday, January 22, 2013 11:39 AM

I really don't understand the 32 gauge and larger crowd for ordinary LEDs.  Yes it will work, but magnet/motor wire has the following advantages:

1.  Highly flexible

2. ~2.5cents/foot

3.  Easy to conceal

Highly flexible wire in larger gauges is usually stranded.  It works, but there's increased risk for breakage in tight corners, or if you yank on the insulation.

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by cacole on Tuesday, January 22, 2013 10:37 AM

TCS also sells 32-gauge decoder wire in multiple colors, 10 feet to a package..

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Posted by gandydancer19 on Tuesday, January 22, 2013 10:05 AM

NWSL carries small flexible wire in small packages.  I have several in various sizes.

However, the best that I have found to date is DCC Decoder wire.  Digitrax sells it and it has all of the colors you will need.  I think it is about AWG 30 in gauge and very flexible.  I got one of their rolls and I don't think I will run out any time soon.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

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Posted by BroadwayLion on Tuesday, January 22, 2013 9:51 AM

LION  seconds the printer cables. I've cut up dozens of them. The older ones have 25 conductors, very nice for many many jobs. The newer ones have 25 pairs of conductors, very fine wire, excellent for signals, the LION also uses them between the cars on his train sets. LION'S subway trains run as 6 car sets, and use these fine wires between the cars to allow for 48 wheel power pickup. It works just fine in that application.

Put a notice in your church bulletin that you are looking for old printer cables, and you will find them piling up on your doorstep.

ROAR

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Here there be cats.                                LIONS with CAMERAS

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Posted by JoeinPA on Tuesday, January 22, 2013 9:48 AM

In those cases where a fine gauge solid wire that isn't very flexible can be used "wire wrap" wire can be used. It has a tough insulation and can be obtained in several colors.

Joe

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Posted by DigitalGriffin on Tuesday, January 22, 2013 9:14 AM

Most LEDs use a very SMALL amount of current.

As the average LED only uses 20ma (.020 amps) you will experience < 0.55% voltage drop / foot @ 12 volts with a 40 gauge wire.

In otherwords, use motor/magnet wire for LEDs and you should be fine, even if you hook up 10 or so.

http://www.walthers.com/exec/productinfo/514-N5038

Doing it yourself is a lot cheaper then buying them premade:

http://www.walthers.com/exec/productinfo/745-1322

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by skagitrailbird on Tuesday, January 22, 2013 9:12 AM

Litchfield Station shows several packages of 30 g stranded wire on its web site.

Roger Johnson
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Posted by cacole on Tuesday, January 22, 2013 9:06 AM

Another source of very flexible, small gauge wire in multiple colors is an old PC serial printer cable.  Today's PCs usually use the USB, Firewire, or wireless connections for printers and other peripherals, instead of an RS232 serial port.  A local computer shop may have old cables they will be willing to give away.

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Posted by mlehman on Tuesday, January 22, 2013 9:01 AM

Jim,

Excellent tip. I tend to reserve the mouse wire for DCC installs, but I'm working out of my own small stock of deceased mice. I need to find a good source of used ones locally then I'll be good.In a university town like this, I just need to go look, I suspect.

When I use new wire for DCC installs, I order 30 or 32 gauge wire with extra-flexible insulation, like that on the mouse wiring or better. While wire gauge is a factor for DCC installs, just as important is how the insulation flexes, particularly for those crucial loco-to-tender connections where you want it to not affect how the tender follows the loco through curves, etc. I tend to use the fancy stuff for this, as the extra cost is well worth avoiding the aggravation that using stiff-insulation wire for those critical connections sometimes causes.

What was a big source for wiring structures in my recent The Night Scene project (http://cs.trains.com/mrr/f/88/t/213765.aspx) were the spare 8-pin plug pigtails that I've scarfed out of decoder installs. I went through a bunch of them. The multiple colors required me to sort out which 4 colors were "red" and which 4 were "black" but that's no big deal with something as mundane as structure lighting. But these are all used up now, so...

Certainly, 22 gauge is way overkill for lighting with LEDs. But that's the smallest stranded, insulated wire that RS carries in bulk rolls. For inside structure lighting, it works so long as you don't need to wire in tight spots or where you'd like to disguise it.

But you can use an alternative that RS carries in some case. They carry a 3-pack of solid wire in 22, 28 and 32 gauges (IIRC correctly, I've thrown the packaging with the info away) usually used for making windings for coils, etc. Each has the transparent coating of enamel (?, dang CRS, not sure it's that or shellac, or?) in a different color. I wouldn't trust that insulation for contact with a similar wire of the opposite polarity, but all you really need to do is to keep the parallel paths from crossing over each other in contact. Not too big a deal, especially when you're only dealing with ~3 volts.

I don't have a closeup of the wiring in my roundhouse, which was done this way, but I could take some if you'd like, This pic does show how unobtrusive it is, as I ran the leads down opposite sides of each of the roof support timbers.



Mike Lehman

Urbana, IL

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Posted by Soo Line fan on Tuesday, January 22, 2013 8:35 AM

PC mouse wire is the best because it is extremely flexible. My wife works in IT and got me some damaged mice. Various colors are contained in the jacket and the size is perfect.

As for a source, go to a computer show. Or call a PC store which does repairs. They usually have a lot of junk stuff lying around.

Ebay is another good source. Search for used PS2, serial or USB mice.

Jim

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Best Wire Sizes for LEDs and Repowering Jobs
Posted by cedarwoodron on Tuesday, January 22, 2013 8:07 AM
I have been using 22gauge stranded wire- that I picked up from Radio Shack- for most of my rebuilding and repowering efforts so far, but I keep running into close-fit situations where a smaller wire would be better. Can anyone give me a set of better and smaller choices for wiring- I keep removing old filament bulb lighting that has very small wires (usually 15+ years old and well- baked) that seems much better than the 22 gauge I now have. Input on this would be greatly appreciated! Cedarwoodron

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