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Lets talk about wiring

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  • Member since
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  • From: Reading, PA
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Posted by rrinker on Monday, February 05, 2018 3:08 PM

One LED, one resistor. Use the specs of the LEDs you are using.

A computer power suppyl works, but many don;t regulate wellw ithotu a decent load on them. A handful of LEDs will not put much of a load on it.

How many LEDs before you smoke a power supply? Well, you did the calculations - you just don't know you have answer. If you put resistors on each LED to limit the current to 5ma, then 10 LEDs will be 50ma, and so forth. Each LED/resistor combo gets wired in parallel with all the others. So you jsut add the currents. Don;t load the power supply to more than 75% of its rated output. So for a 1 amp wall wart, 750ma. That's 150 LEDs if they are all configured for 5ma.

                             --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 mbinsewi on Monday, February 05, 2018 3:17 PM

SpaceMouse
I hear the red spotted muchrooms grow in that part of the country.

Wow man!!! far out!

Mike.

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  • From: Vancouver Island, BC
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Posted by selector on Monday, February 05, 2018 4:55 PM

SpaceMouse

 

 
DigitalGriffin
feeders every 3 feet or so

 

Some people suggest feeders on every piece of track. They say that one should not trust joiners for electrical connections. I suppose I could trust a joiner up to the point of failure...I do have a multi-meter. What about turnouts, do you wire every one?

 

Chip, sorry to resurrect this part of the conversation, but I would recommend only soldering every second set of joiners, and using the soldering process to affix a feeder to the same joiners.  That way, you get positive electrical transmission from that soldered joiner pair outward in both directions for the distance until you encounter the next set of joiners.

In graphic form:

======X=======0========X========0====

You solder only the X's and leave the opens to slide and to let your track system adjust to changing temps and humidity as needed.  If you use DAP Alex Plus with silicon for the adhesive, it will be rubbery and let your tracks squirm just enough to prevent the wows and kinks. (Please only use the stuff that dries 'clear'.  I was not the least bit happy with whatever the 'white' stuff is, but the 'clear variety held well and didn't show up as much.  Note that it is white in the tube, but will dry slightly clear/yellow).

But the point really is to only have to solder every second length of flex, not every length, and that applies to feeding each with robust power as well.

-Crandell

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Posted by betamax on Monday, February 05, 2018 4:58 PM

SpaceMouse

Let's talk about wiring. I figure I'm going to have a lot of questions. So let's start with the little I know about it. Feel free to correct me here.

1) If you are drawing a lot of amps you have to have heavier guage wire. Power tools such as worm-drive saws (draw 13-15 amps depending on manufacturer) need at least 12 guage wire to run 100 feet on a power cord or they suffer from voltage drop and can burn up. They use twisted wire.

2) The same principle applies to house wiring. If you are on a 20 amp breaker you need 10 guage wire. On a 15 amp breaker you use 12 guage wire. Both of these are solid core wire.

3) Data--phones and computer--is trasmitted over some pretty great distances using thin 24 guage solid core wire. For some reason, they twist it. That it is except LocoNet wiring which is a flat ribbon.

4) The smaller the wire, the easier it is to solder to the track and make it look good.

5) Soldering thin wire directly to a solid 12 guage bus isn't as easy as it should be.

 

I want to understand the why of things so I can make decisions about my layout. For instance I have a sufficient length of 12 guage romex residential wire, and a lot of Cat 5--like half a box (250 ft or so 8 strand twisted pairs). I also have some short pieces of 16 or 18 guage solid core wire in red and green--probably enough to do the feeders. 

First 2 questions:

1) What is the advantages or disadvantages of solid wires vs twisted wires?

2) Why are wires transmitting data twisted? I know they suggest twisting bus wires on DCC layouts, but from what I seen in reality on YouTube, the twisting is half-assed (and mostly, I think) to say they did it. 

 

1. I think you mean solid versus stranded.

https://dccwiki.com/Wire_Types

2. Data cables use twisted pairs, and all the wires are twisted carefully together.  There is a lot of engineering in there.  The main purpose is to cut down the impedance, as well as add some protection from interference. Poorly made data cables come with a performance hit built in.

For direct current/analog, impedance isn't an issue.  For DCC, inductance is the problem, and twisting reduces the impedance in the process. For DCC twisting is not required, but the wires should be kept close.

https://dccwiki.com/Wire_Sizes_and_Spacing#To_Twist.2C_or_Not_to_Twist

An extension cord is twisted by design, and uses stranded wire for flexibilty. Keeping the wires close reduces the impedance (Z) of the cord by cutting inductance. (Twisting is not needed to accomplish that.)

Solid wire isn't meant to be abused by repeated bending.  Stranded wire can handle that better, depending on the number of wires and their gauge.

As to house wiring, you might have a 15 amp breaker but the limit is 12A or 1440VA.  (For watts to be valid in AC, you need to know the power factor.)

Digitrax does not recommend using Ethernet cables for Loconet purposes.

 

  • Member since
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Posted by SpaceMouse on Monday, February 05, 2018 4:59 PM

selector
======X=======0========X========0====

Love this.

selector
I would recommend only soldering every second set of joiners, and using the soldering process to affix a feeder to the same joiners. 

Makes sense o me.

Chip

"Rock Ridge and Rock Ridge Lumber are names that really stand for something" --Randal "Rock" Ridge, Mayor and Founder

"Mining is the very foundation of a free America." --Stanley "Stone" Ridge

"Give me Apathy, or give me something else."--Carlton Ridge, aka "The Cat"

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  • From: Texas, USA
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Posted by PennsyNut on Monday, February 05, 2018 5:22 PM

You have now hit upon the way I tried to tell a club I belonged to, but they insisted on wiring each 3' section. Also, they insisted on soldering the feeder to the side of the rail. I laid some (and they didn't know this) with the feeder wire soldered to the bottom of the rail. This was done prior to actual installation. i.e. do this soldering at the table/workbench. Then, as I put the track in place, carefully marked where to drill the hole and placed the track down and that wire was hardly noticable at all. Hidden by ballast. So if you were to solder the feeder to a rail joiner, could be done the same way. And soldering a rail joiner at the "X" to make a totally solid connection. And excellent way to lay track. Leaving that expansion joint every 6' is also good/great. Needless to say, I don't belong to that club anymore. One other thing they did I didn't agree with, was the use of those plastic connectors/suitcase connectors?. I soldered/PERIOD. But I only laid a siding and they got angry with me because I didn't follow their "standards". I know some don't like soldering, but talk to any electrician worth his salt and he'll agree about soldering.

A SPF,Nuts about Pennsy,what else is there?
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Posted by Atchee on Monday, February 05, 2018 9:08 PM

Comments about breakers and house wiring really don't add any pertinant info to a discussion about layout wiring.  The Natural Electrical Code tables used for such impose limitations because of things not normally present under a layout and the type of insulation on the wire

For example,  #14 NM-B (Romex) is limited to a 15 AMP breaker in most applications, but is rated at 25 AMPs in the code book.  Those same wires not in a cable, but in free air (under layout wiring) are rated at 35 AMPs.

The meat of the thing is that a #12 buss wire on a 12 volt supply will supply about 11.2 volts at 5 AMPs at 50 feet, about a 6% drop, or 11.77 volts at 25 feet, a 3+% drop.  At a 2.5 AMP load, the drops are about 3% and 1.5% respectively.  Also keep in mind that if you use rail joiners (I don't) and feed each or every other piece of rail, the voltage drop will be even less as the rail will act as a parallel conductor. 

A #24 wire will give roughly these same results in 2 feet, a bit of a caution in trying to use too much small wire in hooking up loads, like a foot long piece from rail to feeder.

Communications cables are twisted to BASICALLY eliminate two things.  Crosstalk between pairs and 60Hz noise.  Quite a science involved to reject all this stuff and is why different pairs are twisted more or less times per meter than others.

 

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Posted by rrinker on Monday, February 05, 2018 9:42 PM

What Selector said is exactly what I did. I soldered two pieces of flex together, then connected it to another 2 pieces soldered together, but did not solder that joint between the two. However, I did have feeder wires to the joiners between the two sections as well - other than where I needed an insulated joiner, EVERY joiner on my layout had power feeds. Overkill? perhaps, but I never had stalling issues and I never cleaned my track. I barely dented a spool of the #20 wire I used for the feeders - even with a 12x15 or so around the room layout, there aren;t as many track joints as you might think, at least when using flex track. 

                        --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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  • From: North Dakota
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Posted by BroadwayLion on Friday, February 09, 2018 10:33 AM

LION did NOT read the whole thread, but there are some considerations that you want to take into account...

 

HO scale amps are different from 110 volt amps.

Our place has 40 amp breakers out on the utility pole, but that is at 4600 volts. We have dozens of 400 amp fuses (breakers) inside our building at 110 volts. On the layout Amps are measured at perhaps 12 volts.

So if you have so many lamps on your layout and they draw say 3 amps at 12 volts (a reasonible number and fused as such) the transformer will draw a small fraction of an amp on the 110 volt side.

 

Ergo you do not size your 110 volt fuses for what your layout is drawing on the 12 volt side, but rather how much amps are the transformers drawing on 110 volt side of the layout.

Layout of LION draws perhaps 25 amps on the HO side of the layout, but only 2 or 3 amps on the 110 side of the system.

 

WHEN installing bus wires under the layout, I use either 12 or 14 ga wire, not because my power supply puts out 15 amps, but because electricity tries to travel on the outside of the wire not on the inside. 12 ga wire has more outside than a 22 ga wire, and thus it can carry the required power for longer distances with less resistance losses in the wire.

Some people tell me I am full of LION POO, but it is the SLOWER speeds that you loose with the smaller wires. This is because you must increase the voltage to move the power through a small wire than you would require with a larger wire.

Look at the power pole outside of our buildings, they are pushing power at 4600 volts through relativly small wires, once they pass the transformers (ostside of the building) the same power requires much heavyer wires, mutiple wires in fact for each leg of the transformer.

I do not need the big bus wire for 15 amps at 12 volts, but the trains sure know the difference. But again smaller drop wires from the tracks to the buys are fine, they travel only a short distance and introduce little resistance to the circuit.

 

Now as for the wires themselves...

LION uses regular 12 or 14 ga solid building wires for the buses of him. but for all other service him uses 22 ga wires.

You can have SOLID WIRE, self explanatory, they are difficult to install because they are not very bendy.

You can have STRANDED wire, which is many small solid wires twisted together into a single but very flexible conductor. Easy to install, but a PITA if a single strand of wire reaches out from your connection to the track to poke itself at the passing train or cause a short with an adjoining wire. (LION has had both problems.)

 

Then there is TWISTED WIRE or twisted pairs...

This is a twisted pear...

It is used in computer networks. Cat 5e wire has more twists per inch than cat 5 wire. Cat 6 wire has even more twists per inch, but of the four pears in each wire, each pair has a different number of twists, AND there is a plastic separator inside of the cable so that the four pair twist among themselves at a very specific rate, maybe one full twist per yard of cable.

Very important to computer network designers, but rather moot on your HO scale railroad. Cat 5e wire is available solid or stranded, use the solid throughout your computer network, but use the stranded when you make patch cables. On you layout stick with the soplid.

 

IT IS FAR CHEAPER TO BUY CAT 5 WIRE and tear it apart than it is to buy a like amout of 22 ga solid wire. LION KNOWS, him has priced it all out, 'cause LIONS ARE CHEAP!

LION has 14 miles of track, him has lots of track detectors, relays, signals, switch motors etc etc and so him has many conductoirs between Power central and the railroad. HIM bought 25 pair CAT-3 cable for this (50 conductors) to bring signals etc to the layout.

Here is cable interface of LION only half wired--these are the cables from power control out to the layout, since this picture was taken the rest of the interlocking plant has been connected to these terminals.

: )

LIONS *like* complicated.

 

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by SpaceMouse on Sunday, February 11, 2018 1:48 PM

Thanks for the info, Lion. 

BroadwayLion
This is a twisted pear...

LOL

BroadwayLion
IT IS FAR CHEAPER TO BUY CAT 5 WIRE and tear it apart than it is to buy a like amout of 22 ga solid wire. LION KNOWS, him has priced it all out, 'cause LIONS ARE CHEAP!

Mice are pretty cheap, too. But you left something out. It's even cheaper if you have half a 500 ft roll left over from when you wired home networks. 

Chip

"Rock Ridge and Rock Ridge Lumber are names that really stand for something" --Randal "Rock" Ridge, Mayor and Founder

"Mining is the very foundation of a free America." --Stanley "Stone" Ridge

"Give me Apathy, or give me something else."--Carlton Ridge, aka "The Cat"

  • Member since
    February, 2002
  • From: Reading, PA
  • 23,620 posts
Posted by rrinker on Sunday, February 11, 2018 6:10 PM

 And someone wonders why I 'cluttered' the garage with the most of a box I snagged from work that was going to be thrown out (it's only Cat 3 so no good to wire the house - but on the layout...).

                                   --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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