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Stranded or Solid?

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Stranded or Solid?
Posted by Trainzman2435 on Sunday, December 15, 2019 5:35 AM

So after reading all over the net i am wondering, what is your preferred DCC BUS wire, stranded or solid? I have decided to go with 14 AWG but i am not sure which to go with, stranded or solid? Any tips or help is appreciated.....Thanks!

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Posted by betamax on Sunday, December 15, 2019 6:22 AM

It does not really matter if the wire is solid or stranded.  It makes no difference electrically.

For your DCC Bus, stranded is the better choice, as it can withstand flexing during installation, routes easily, and is less likely to be damaged when stripping the insulation.

The gauge of the wire is also important. You did not mention which scale you are working in.  Short bus runs in H0 can use 14AWG, for longer runs 12AWG is recommended.

https://dccwiki.com/Wire_Sizes_and_Spacing

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Posted by gregc on Sunday, December 15, 2019 6:42 AM

suitcase connectors work better with solid wire.    They are for two different gauges.   18g bus and 22g feeders are appropriate.   

greg - Philadelphia & Reading / Reading

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Posted by SPSOT fan on Sunday, December 15, 2019 8:26 AM

Each option has it’s own advantages and disadvantages, but I generally prefer stranded wire, because if you bend a solid wire to much it has the possibility of snaping, and when there is only one solid wire, that means you’ve need to replace the wire. With stranded their a number of redundant wires which will hold up better. The disadvantage is stranded it a bit hard to solder but if you twist the wire and them tin it, it will be a lot easier to solder (you should probably tin irregardless).

Regards, Isaac

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Posted by rrinker on Sunday, December 15, 2019 12:40 PM

 Does not matter, but I always use stranded because when you get to the larger sizes like #14 and #12, it's a whole lot easier to pull around under the layout if it's stranded. I use solid for the feeders, so there is no chance of a stray strand at the rail.

 I don't use suitcase connectors, so that's a non-issue. What isn't soldered goes to terminal blocks and I put ring terminals on the ends of the wire for that. The trick to soldering bigger wire sizes like that is to use the approriate tool. The low wattage iron you use to install decoders or solder feeders to the rail will never heat it up enough, or it will, EVENTUALLY, after spreading the heat a foot to either side of where you are trying to solder. Soldering feeders to a heavy gauge bus is where you want that 150 watt or larger soldering gun.

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Posted by wvg_ca on Sunday, December 15, 2019 12:48 PM

I used 10 gauge solid for my layout , eight different runs with spade connectors onto the [lit] switches ..

For the feeders I used stranded wire from printer cables to go up, every three feet or so .. It was just what was handy at the time, none of it was bought for purpose,

Whatever works for you, within reason I suppose ..

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Posted by Trainzman2435 on Sunday, December 15, 2019 1:03 PM

Thanks to all of you guys for your input. I ended up going with 14 AWG for my N scale layout and i plan to use suite case connectors and terminal blocks....Thanks again!

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Posted by gregc on Sunday, December 15, 2019 2:38 PM

i think suitcase connectors for 14g solid wire match 18g.   would you use 18g for feeders?

greg - Philadelphia & Reading / Reading

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Posted by doctorwayne on Sunday, December 15, 2019 2:55 PM

I recall reading somewhere that DCC simplified wiring, as compared to DC. 

Here's what powers my layout, with approximately 260' of mainline which doesn't include staging, double track or industrial sidings (all track is soldered together)...

Admittedly, as the sole operator, I don't run more than one train at a time (no "blocks" to allow it), but I have run more than a dozen locos at one time, and usually run two or three locomotives on most trains, due to the many curves and relatively severe grades.

Because the layout is point-to-point (multiple points), it's not suited to multiple operators, nor is having additional operators desireable.

However, to answer the original question, if I were to convert to DCC, I'd still solder the track together, and use only two feeders, but perhaps with somewhat heavier wire. 

However, not being all that conversant in DCC (I recently built a Bowser steamer for a friend, though, and successfully installed DCC in it), I'm wondering why I haven't read of anyone doing it in this manner, as it would save a lot of work (and wire). 
If my DC equipment can push 12 volts through all that track with no voltage drops (none of those locos slowed appreciably as another was added), then I'd think that a decent DCC system could accomplish the same with its 15 volt output. 

Obviously the rail is a decent conductor and larger than the wire gauges mentioned, so I'd think that the additional digital info in the DCC output would not be impeded, either.

Has anyone tried running their DCC layout with soldered rail joints and no bus wire?

Wayne

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Posted by richhotrain on Sunday, December 15, 2019 3:44 PM

Wayne, are you saying that you run 260' of mainline track, all soldered, off a 12 volt DC power pack with one pair of feeders and no voltage drop? 

Rich

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Posted by ATLANTIC CENTRAL on Sunday, December 15, 2019 4:02 PM

richhotrain

Wayne, are you saying that you run 260' of mainline track, all soldered, off a 12 volt DC power pack with one pair of feeders and no voltage drop? 

Rich

 

I only run one reeder to each block, sometimes 60-70 feet of track, I have never had voltage drop issues in DC.

Like Wayne I solder all my rail joints within each block.

Wayne's example is only 3-4 times my longest blocks....

I do run a #12 wire throttle buss around the room from the wireless throttle base stations, then local relay panels assign blocks to throttles via 18 gauge drops.

Sheldon

    

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Posted by rrinker on Sunday, December 15, 2019 4:11 PM

 My old layout, an 8x12 donut double tracked - well, I TESTED it by just hooking one pair of feeders to the DCC system, and trains ran fine (and all joints weren't even soldered - none of the turnouts were soldered, just the joints between sections of flex track in between).

                            --Randy


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Posted by gregc on Sunday, December 15, 2019 4:25 PM

doctorwayne
Obviously the rail is a decent conductor and larger than the wire gauges mentioned,

this Rail Size page from DCC Wiki says code 83 is the equivalent of 26g wire which has a resistance of 42 Ohm/1000ft

if Wayne attached power to the middle of his 260 ft run, the longest distance from the feeder is 130' or  5.5 Ohms which would have a drop of 5V at 1A at that distance, only 0.5V for 100 ma of a more efficient motor, again at that distance.  (half if connected at both ends)

maybe an 18g bus (6.5 Ohm/1000ft) is overkill on most layouts

 

 

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Posted by ATLANTIC CENTRAL on Sunday, December 15, 2019 4:35 PM

gregc

 

 
doctorwayne
Obviously the rail is a decent conductor and larger than the wire gauges mentioned,

 

this Rail Size page from DCC Wiki says code 83 is the equivalent of 26g wire which has a resistance of 42 Ohm/1000ft

if Wayne attached power to the middle of his 260 ft run, the longest distance from the feeder is 130' or  5.5 Ohms which would have a drop of 5V at 1A at that distance, only 0.5V for 100 ma of a more efficient motor, again at that distance.  (half if connected at both ends)

maybe an 18g bus (6.5 Ohm/1000ft) is overkill on most layouts

 

 

 

And this points to another basic difference between DC and DCC.

Wayne is only powering one train at a time. 

I am only powering one train per active block.

Not a whole layout of different operators.......

My wireless throttles each have their own 4 amp regulated power supply that only has to respond to at most three or four modern loco motors in blocks 30 to 70 feet long.

Never any issues.

Sheldon

 

    

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Posted by richhotrain on Sunday, December 15, 2019 4:40 PM

ATLANTIC CENTRAL
 
richhotrain

Wayne, are you saying that you run 260' of mainline track, all soldered, off a 12 volt DC power pack with one pair of feeders and no voltage drop? 

Rich 

I only run one reeder to each block, sometimes 60-70 feet of track, I have never had voltage drop issues in DC.

Like Wayne I solder all my rail joints within each block.

Wayne's example is only 3-4 times my longest blocks....

I do run a #12 wire throttle buss around the room from the wireless throttle base stations, then local relay panels assign blocks to throttles via 18 gauge drops.

Sheldon 

At what length of soldered track does voltage drop begin to occur on a 12-volt DC powered layout?

Rich

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Posted by doctorwayne on Sunday, December 15, 2019 4:40 PM

richhotrain

Wayne, are you saying that you run 260' of mainline track, all soldered, off a 12 volt DC power pack with one pair of feeders and no voltage drop? 

Rich

 
That's correct, Rich, but do keep in mind that mine is not a block-type system, where more than one train can be operated independently from other ones also in motion.

This was easily accomplished with gaps in one rail, and a wire dropped to a simple on/off switch on the fascia - a foot or two of wire at most of those many locations. 

My layout was wired with the common rail system outlined in the Atlas book, but not using the Atlas current-controlling devices.  Simple to install and operate, and simple to trouble-shoot, too.

Running the dozen-or-so locomotives at one time was/is a game I play when my grandkids simply wanted to "see the trains run".  I'd put one on the track and they'd walk around the layout following it.  While they were thus engaged, I'd place another loco on the track, and continue adding locos, much to their surprise, in the same manner.
When it came time to wrap-up the session, I'd simply grab one off the track as it passed, until we were down to just one in motion.  At that point, I'd let the oldest or most-interested one run it to where I wanted it parked.
 
Two of them (3 & 6 years old) are still interested in the trains, but the others have pretty-well moved on.

Like my kids, all of my grandkids are respectful of the models - I let them touch certain things at certain ages, and let them run the trains, too, but they're well aware of the fragile nature of most items, and are very considerate of those limitations.

Wayne
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Posted by richhotrain on Sunday, December 15, 2019 4:42 PM

doctorwayne
 
richhotrain

Wayne, are you saying that you run 260' of mainline track, all soldered, off a 12 volt DC power pack with one pair of feeders and no voltage drop? 

Rich 

That's correct, Rich, but do keep in mind that mine is not a block-type system, where more than one train can be operated independently from other ones also in motion.

At what length of soldered track does voltage drop begin to occur on a 12-volt DC powered layout?

 

Rich

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Posted by ATLANTIC CENTRAL on Sunday, December 15, 2019 5:07 PM

richhotrain

 

 
doctorwayne
 
richhotrain

Wayne, are you saying that you run 260' of mainline track, all soldered, off a 12 volt DC power pack with one pair of feeders and no voltage drop? 

Rich 

That's correct, Rich, but do keep in mind that mine is not a block-type system, where more than one train can be operated independently from other ones also in motion.

 

 

At what length of soldered track does voltage drop begin to occur on a 12-volt DC powered layout?

 

 

Rich

 

As Greg pointed out, voltage drop is a function of distance and current, so with modern low current equipment, the rail is an effective conductor for a pretty long distance.

If I was building a DCC layout, I would use more power districts, lower current circuit breakers and not worry about all this feeder buss.

Sheldon

    

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Posted by richhotrain on Sunday, December 15, 2019 5:13 PM

ATLANTIC CENTRAL
  

As Greg pointed out, voltage drop is a function of distance and current, so with modern low current equipment, the rail is an effective conductor for a pretty long distance.

If I was building a DCC layout, I would use more power districts, lower current circuit breakers and not worry about all this feeder buss.

That is my solution to the voltage drop issue, more power districts and shorter sub-bus wires. But, I operate in DCC and my understanding is that DCC, as well as AC, is more sensitive to voltage drop than DC.

Rich

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Posted by RR_Mel on Sunday, December 15, 2019 5:47 PM

I might as well jump in and muddy up the topic.
 
I have 121’ of Atlas Code 83 NS Flex Track in a twice-around.  I use Walthers 948-841 NS rail joiners.  The 948-841 joiners fit extremely tight, none soldered.
 
I have two long blocks of 13’ (paralleled) the rest average 8’.  I feed each block with #20 solid twisted pair (Bell Wire) from my control panel.  All 15 blocks are homeruns to a DPDT center off toggle on my control panel. 
 
My norm is a pair of very heavy E7s (34 oz each) at wheel slip draw 600ma or 1.2 Amps for the pair or a single heavy Cab Forward that draws about 580ma at wheel slip.
 
The max voltage drop I’ve measured is .6 volts using my Fluke 179 meter.  I haven’t measured the actual length of each pair of #20 wires but I would estimate the longest at 20’.  I do not use separate feeders for each section of Atlas track nor do I power the frogs separately.
 
Even running more than one train there will only be one train in a block at a time thus well under the max rating of #20 AWG wire.
 
I operate Dual Mode on my layout, DC or DCC.  I’ve never had a power problem on my layout in over 30 years.
 
This is my layout with the helix extended, the dashed tracks are hidden.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by RR_Mel on Sunday, December 15, 2019 6:04 PM

Problem on the site caused a dual posting.

 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by BigDaddy on Sunday, December 15, 2019 6:38 PM

gregc
i think suitcase connectors for 14g solid wire match 18g.   would you use 18g for feeders?

They come in a variety of sizes.  The 3M 905 accomodates 18-22ga for the tap and 18-14 ga for the run

Henry

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Posted by gregc on Sunday, December 15, 2019 6:45 PM

richhotrain
But, I operate in DCC and my understanding is that DCC, as well as AC, is more sensitive to voltage drop than DC.

AC signals are affected by inductance and capacitance.   I would think any affect is very small because their values are both small and DCC is at relatively low freq (<10kHz). 

the other benefit of DCC is that while voltage drop does affect the voltage reaching a decoder, the decoder may not be applying full voltage to the motor and can maintain a constant motor voltage when using BEMF.

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Posted by gregc on Sunday, December 15, 2019 6:51 PM

BigDaddy
gregc
i think suitcase connectors for 14g solid wire match 18g.   would you use 18g for feeders?

They come in a variety of sizes.  The 3M 905 accomodates 18-22ga for the tap and 18-14 ga for the run

my understanding is that for the 905, it accomodates 14g stranded or 18g solid (run).

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Posted by rrinker on Sunday, December 15, 2019 7:04 PM

You have to double those voltage drop calculations - if the feeder is in the middle, and the loco is 130 feet away from the feeder, that's 260 feet of 'wire'

                                --Randy

 


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Posted by gregc on Sunday, December 15, 2019 7:10 PM

right.  thanks

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Posted by Attuvian on Sunday, December 15, 2019 7:29 PM

betamax

It does not really matter if the wire is solid or stranded.  It makes no difference electrically.

 
I suspect I am about to be schooled on the subject, but my recollection of my old Navy electronics training says that there IS an electrical difference, at least between wiring of the same gauge.  I was told that current does not pass through the entire mass of a wire, but on its surface.  On that basis, 14 gaage stranded, having a far greater total surface area per unit length than solid, has a greater efficiency (less resistance?) to pass current.  Now, for our applications, those effects may well take a back seat to other ones like flexibility, especially on smaller layouts with shorter busses.  Guess I'm mostly nit-picking here, with a hat tip to Betamax for his post.
 
But now that I think of it, much of the stuff I heard in the Navy on virtually every other subject was highly suspect.  That spirit sometimes made its way into technical, classroom subjects to embarass both the simple and the unsuspecting!
 
Wink
 
John
 
 
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Posted by betamax on Monday, December 16, 2019 1:14 AM

doctorwayne

I recall reading somewhere that DCC simplified wiring, as compared to DC. 

 

However, not being all that conversant in DCC (I recently built a Bowser steamer for a friend, though, and successfully installed DCC in it), I'm wondering why I haven't read of anyone doing it in this manner, as it would save a lot of work (and wire). 
If my DC equipment can push 12 volts through all that track with no voltage drops (none of those locos slowed appreciably as another was added), then I'd think that a decent DCC system could accomplish the same with its 15 volt output. 

Obviously the rail is a decent conductor and larger than the wire gauges mentioned, so I'd think that the additional digital info in the DCC output would not be impeded, either.

The simple answer is that DC is not the same as DCC.

With DC, as your locomotive slows you crank up the voltage a little more.  

With DCC, the decoder controls the speed, as the voltage decreases it will slow down as the motor is controlled using PWM, where time, not amplitude, determines the speed.

The more complex answer is that DCC, being a square wave, is rich in harmonics. Harmonics do no work, but they do cause problems. Hence the need for more robust wiring.

 

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Posted by betamax on Monday, December 16, 2019 1:32 AM

Attuvian

 

 
betamax

It does not really matter if the wire is solid or stranded.  It makes no difference electrically.

 

 

 
I suspect I am about to be schooled on the subject, but my recollection of my old Navy electronics training says that there IS an electrical difference, at least between wiring of the same gauge.  I was told that current does not pass through the entire mass of a wire, but on its surface.  On that basis, 14 gaage stranded, having a far greater total surface area per unit length than solid, has a greater efficiency (less resistance?) to pass current.  Now, for our applications, those effects may well take a back seat to other ones like flexibility, especially on smaller layouts with shorter busses.  Guess I'm mostly nit-picking here, with a hat tip to Betamax for his post.
 

 
Thanks.
 
At audio frequencies, the skin effect is minimal. Especially considering the currents involved.
 
At high currents, it is all about the surface area.  Even at 60Hz.
 
 
 
 
 
 
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Posted by doctorwayne on Monday, December 16, 2019 7:39 AM

betamax
...With DC, as your locomotive slows you crank up the voltage a little more....

Perhaps on a grade with a heavy train, but for the episodes with the dozen locos, the throttle was set to a medium-slow speed, and not adjusted at all.

betamax
With DCC, the decoder controls the speed, as the voltage decreases it will slow down as the motor is controlled using PWM, where time, not amplitude, determines the speed.

My DC walk-around throttle also puts out PWM current - perhaps that explains the situation, although none of my locos have decoders.

Wayne

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