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Which wire gauge do I use?

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Which wire gauge do I use?
Posted by train_frk-0079 on Saturday, January 31, 2009 5:13 PM

While I was starting to lay the track to my yard, I ran into a problem.  What gauge of wire do I use?  I know from my previous DC layout that electrical power gets lower the farther it travels.  If I go about 12ft., what gauge of wire do I use for the bus?  What gauge for the feeder wires?  Anybody experienced in wiring, or knows what they are doing, sound off.

Peace

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Posted by retsignalmtr on Saturday, January 31, 2009 6:15 PM

it depends on the length of the run. a 12' run could use 16awg or 18awg wire for the buss with a 20awg to 24awg feeders to the rail from the buss. my buss run on my n scale layout will be 70' long using 14awg stranded wire with 20awg for the feeders. i used 14awg because i got it for free and had it on hand when i began building my layout.

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Posted by dstarr on Tuesday, February 3, 2009 11:51 AM

 #16 AWG (the size wire used in lamp cords) is enough for buses on all but the largest layouts.  Lots of people use #14 AWG house wire 'cause its readily available and mechanically rugged.  Electrically its bigger than necessary, but that doesn't hurt anything.  I don't use #12 AWG house wire because it is too stiff to bend easily with long nose pliers. Feeder wires (short feeders that is) can be thinner.  #22 or #24 AWG or even smaller works. 

  You can find a "copper wire table" on the Internet.  Such a table will give you the diameter in inches and the resistance in ohms per foot, or ohms per 1000 feet.  

As a rule of thumb, the wire is thick enough if the voltage drop is less than one volt. Voltage drop V = IR where I is current (in HO use 1 amp for planning purposes) and R is the resistance of the wire going out AND coming back.  Or, for HO, just keep resistance down below one ohm.  

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Posted by Texas Zepher on Tuesday, February 3, 2009 1:48 PM

train_frk-0079
What gauge of wire do I use?

What size do you have laying around?

I know from my previous DC layout that electrical power gets lower the farther it travels.  If I go about 12ft., what gauge of wire do I use for the bus?

In my opinion 12 feet is not long enough for a bus.  Just run two wires down the center of the yard (crosswise to the track) connecting one to each left rail and the other to each right rail.  The "bus" then becomes the width of the yard.  In general the size of a wire needed in bus has more to do with the number of locomotives and/or power consumption demanded on the track being wired.  Very few people have 30 feet and longer wires where the voltage drop becomes a factor - and then once again only if a lot of current is needed at that far end.  If this is a coach yard that will contain bunches of lighted passenger cars that have incandesent lamps in them the gauge might need to be quite big.  If this is a freight yard and there will only be one locomotive at a time working it, the gauge can be small.  

What gauge for the feeder wires?

I like small solid wire (like 22 gauge) because it is easier to solder to the rails.

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Posted by geomodelrailroader on Thursday, October 4, 2018 12:25 AM

go with 16, 18, 20, or 22 Do not use 12. 12 gauge wire is stiff and it has a nickle core plus you risk overload if you use this. Use solid for the feeders and stranded for the bus. 

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Posted by rrinker on Thursday, October 4, 2018 6:56 AM

 How can larger wire cause an overload? The only strain larger than necessary wire puts on anything is on your wallet. And both rolls of #12 I have are all copper strands, there is no nickle core.

                           --Randy

 


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Posted by betamax on Thursday, October 4, 2018 4:51 PM

geomodelrailroader

go with 16, 18, 20, or 22 Do not use 12. 12 gauge wire is stiff and it has a nickle core plus you risk overload if you use this. Use solid for the feeders and stranded for the bus. 

 

I doubt 12AWG has a nickel core.  Nickel is expensive, so it would not be used with wire.  Plus it increases resistance in the process. Not a desireable outcome for electrical conductors.

Some wires are copper clad aluminum or steel, but they have specialised applications and often are not found at the local hardware store.

I fail to see how heavy wire would cause an overload.  My CT test set's power supplies have no trouble driving large currents through much heavier wires. 

 

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Posted by BigDaddy on Thursday, October 4, 2018 4:54 PM

It's been 9 years since the OP asked this question.  I hope he's got it figured out by now.

Henry

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Posted by MisterBeasley on Friday, October 5, 2018 10:08 AM

I used 18 gauge bus wire.  It was a big, room filling layout with bus runs of 25 feet.  I typically ran 4 sound engines at a time, with lighted passenger cars and cabeese.  I had a few DCC controlled turnouts, too.

I never had track power issues.

Sure, 12 gauge bus wire is nice, but for anything less than a club sized layout it's overkill.

It takes an iron man to play with a toy iron horse. 

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Posted by riogrande5761 on Friday, October 5, 2018 10:53 AM

Uh oh, someone is necroing 9 year old topics and people answering like it is still a current issue, no pun in tended.

SOP for this forum!  Look at dates before answering might be a good idea!

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by CGW121 on Friday, October 5, 2018 11:09 AM

Most forums that  have been a member of, it is considered bad form to dig up old posts. I think it should be here as well.

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Posted by riogrande5761 on Friday, October 5, 2018 11:12 AM

CGW121

Most forums that  have been a member of, it is considered bad form to dig up old posts. I think it should be here as well.

Or even against the rules in some case I've seen.  I can only assume topics get necroe'd here because someone does a search and finds a topic of interest and doesn't check to see if it is current or dredging up ancient history. 

In some cases people post or answer questions to members who are no longer living.  And then others come in like lemmings and follow suite.  Clown

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by MisterBeasley on Friday, October 5, 2018 12:24 PM

Model Railroading, though, is not a static hobby, and there are always new modelers just starting out.  The questions are no less valid now, although some of the answers may reflect newer thinking and newer materials.

9 years ago, no one was willing to admit that a small layout didn't really need a 12 gauge track bus, for example.  We were told to make "wet water" with water and dish soap and make a mess by spraying it around, rather than simply dribbling on a small amount of alcohol from a pipette.

Old threads can have their place.

It takes an iron man to play with a toy iron horse. 

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Posted by Rangerover1944 on Sunday, October 7, 2018 12:49 PM

sounds to me like "****** if you do and ******* if you don't"....imagine that, a newcomer using the search instead of post the question....yup, bet 10 dollars to donuts, someone would have advised him to do a search...

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Posted by geomodelrailroader on Monday, November 25, 2019 4:46 AM
it has to do with voltage if you have larger wire more volts will be flowing through it. 12 is only used for G Scale since it is outdoors and it runs off of a car battery or a transformer. 20 is the feeders for HO and S and O Scale and 16 is the feeders for N and Z. I have gauge 20 wire I will use this for my HO trains no use using it for N Scale I am stuck with my black wire which is 22. Here are the gauges and the link to them don't overload your layout. Z Scale Buss 16 max is 14 Feeders 24 to 22, N Scale Buss 16 max is 14 Feeders 24 to 22, HO Buss is 16 max is 12 Feeders are 20 or 24, O Buss is 14 max is 10 Feeders are are 16 or 22, S same deal, and G Scale Buss is 12 max is 10 you can go up to 14 Feeders are 14 to 20. https://ncedcc.zendesk.com/hc/en-us/articles/115003102886-Recommended-Wire-Gauges-by-Scale
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Posted by richhotrain on Monday, November 25, 2019 4:49 AM

BigDaddy

It's been 9 years since the OP asked this question.  I hope he's got it figured out by now. 

How about 10 years later?  Laugh

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Posted by rrinker on Monday, November 25, 2019 6:48 AM

 He finally got around to answering (incorrectly) the question I asked him a year ago.

                                    --Randy


Modeling the Reading Railroad in the 1950's

 

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Posted by rrinker on Monday, November 25, 2019 6:56 AM

geomodelrailroader
it has to do with voltage if you have larger wire more volts will be flowing through it. 12 is only used for G Scale since it is outdoors and it runs off of a car battery or a transformer. 20 is the feeders for HO and S and O Scale and 16 is the feeders for N and Z. I have gauge 20 wire I will use this for my HO trains no use using it for N Scale I am stuck with my black wire which is 22. Here are the gauges and the link to them don't overload your layout. Z Scale Buss 16 max is 14 Feeders 24 to 22, N Scale Buss 16 max is 14 Feeders 24 to 22, HO Buss is 16 max is 12 Feeders are 20 or 24, O Buss is 14 max is 10 Feeders are are 16 or 22, S same deal, and G Scale Buss is 12 max is 10 you can go up to 14 Feeders are 14 to 20. https://ncedcc.zendesk.com/hc/en-us/articles/115003102886-Recommended-Wire-Gauges-by-Scale
 

 I really think you need to go back and study up on basic electricity. A heavier wire has more CAPACITY, but it can't push more 'volts' all by itself. You have a voltage source, the power pack, or car battery, or what have you. It's 12 volts (ok, 13.8 for a car battery). If you run 50 feet of #22 wire and measure the voltage with a meter at the other end, it's going ot be the same 13.8 volts. If you repalce the #22 wire with 50 feet of #12 wire, you are claiming the voltage will be higher - no it won't, it can't, that violates the laws of physics. It will be the same 13.8 volts.

And the other part of the current flow, the amps - you don't 'push' amps. You can use a 2 amp power supply to run a 1 amp load, you can use a 20 amp power supply to run a 1 amp load. The 20 amp load doesn't 'force' 20 amps into the 1 amp load. 

The wire size difference is the voltage DROP, or loss under a load. If you repeat the same experiment with the #22 and #12 wire, but this time also connect a 2 amp load at the far end, the #22 wire will show less than 13.8 volts because the wire is too thin to carry that much current that far. Even the number 12 wire will show less voltage, just not nearly as much of a drop as the #22.

 Boggles my mind how some of these ideas get started. The 'recommended' sizes for feeders has nothing really to do with the volts but everything to do with appearance. You N scale trains wouldn;t fry because you used #18 feeders, but a piece of #18 soldered to N scale rail would look hideous and be hard to disguise. If you want, I'll solder some #14 to a piece of HO flex track and make a video showing my locos don't catch fire because they magically get more volts than my DCC system puts out. 

                                    --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 MisterBeasley on Monday, November 25, 2019 2:41 PM

Rangerover1944

sounds to me like "****** if you do and ******* if you don't"....imagine that, a newcomer using the search instead of post the question....yup, bet 10 dollars to donuts, someone would have advised him to do a search...

 

Who ever did a search and found something on this forum is a miracle worker, for sure.

It takes an iron man to play with a toy iron horse. 

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Posted by rrinker on Monday, November 25, 2019 5:39 PM

 Easiest thing to do it use Google. Half the time, if something come sup here, and I google the question, I end up getting a link to an old forum thread on the same subject.

                                            --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 gmpullman on Monday, November 25, 2019 6:05 PM

rrinker
Easiest thing to do it use Google.

Yes.

And if you add "site:cs.trains.com" after your search word(s) your search results will be constrained to all the Kalmbach magazine sites.

Regards, Ed

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Posted by Slowmodem on Sunday, December 15, 2019 10:49 PM

I came to this thread because of a 12/12/19 Model Railroader newsletter.

http://link.mail.trainsmail.com/YesConnect/HtmlMessagePreview?YydmZ0LbyqvU5UjHEzhtA5LgN7g4FdLB0AELoaHWY6I=.enc&msgVersion=web

Greg Whitehead

Ironically, I live in the only county in Tennessee with no railroad tracks.

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Posted by BigDaddy on Monday, December 16, 2019 10:35 AM

Greg there are a couple reasons why people don't like old threads in this forum.

More often than you would think possible, it's someone's first post and he thinks he is telling someone how to do something 5, 10 or 15 years later after the question was asked. 

Second, many of the participants in the thread haven't been in the forum for years, i.e. anyone with a forum name of Anonymous

Third the links, especially picture links to Photobucket are dead.

Forth the resurrection of the thread attracts a bunch of people who have to say "me too" (in the old sense of the phrase Big Smile), or that missed that it is an old thread and the OP is waiting for their answer.

I don't think anyone objects to new information in an old thread, but the search function of the forum leaves much to be desired.

You can start a new thread for free.

 

 

Henry

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Posted by Overmod on Monday, December 16, 2019 12:37 PM

Perhaps the method we used in the Yahoo Group steam_tech is something everyone here could agree on as 'netiquette' going forward, and possible inclusion in the TOS and individual forum rules:

1) All threads to stick to designated topic, good or bad.  If it drifts more than peripherally into a different subject, we should start a new topic explicitly based on that different subject.  There are many instances here where a whole good line of discussion is buried inside a thread with a completely different subject or supposed topic.

2) If you pull up an old thread in a search, or because interested in a topic, make a note of its date and time of posting (or its URL in the browser line) and reference that explicitly in a new post on the same, or a suitably adjusted, topic.  

"I saw that in 2008, in this thread (insert or paste URL or reference), tender motors driving the tender trucks were considered an alternative to using a driveshaft between tender and locomotive.  Have there been improvements since then?  Who has experience or thoughts?"

That gives anyone interested in answering a direct link to what prompted the question, so if they're concerned about 'answering a question twice' they can go back and see what the OP of the new thread 'already knows' by reading that thread.  

3) There's no sin in posting the same information twice or more.  We can assume that every few years a new cohort of people will find this site and start wanting to learn.  Ignorance is not stupidity, and at least in my opinion it is about as easy to answer the question as to give them the analogue of RTFM.  (I learned the importance of this through hard experience, some of it here, some rather recently...)  

Of course it's also possible to answer by quoting the URL or even the general context or likely keywords of prior threads ... just as long as the OP doesn't then start responding to posts in them!

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