Im changing my DC layout to DCC. I plan to run a 12 Ga power Bus. What Gauge do the feeders need to be? How long can they be? I've red posts and articles that say everything from 22 - 16 Ga
Gary
My club uses 24 gauge feeders to a 12 gauge bus. Each feeder is up to a foot long.
14, 16 and even 18 is overkill and harder to hide when soldered to the side of rail.
The two most referenced websites (wiring for DCC and DCCwiki) both suggest 22 awg as the smallest wire appropriate for feeders. Anything larger than 18 is overkill.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
You get many opinions because there is no one right answer. At the end of the day the real question is how much voltage drop will there be versus how much voltage drop are you willing to live with. Just as economists always reply, the answer begins with "It depends". There are many variables to be considered:
Because of these variables it is nearly impossible, and misleading, to make a blanket recommendation.
For somewhat of an answer:
Assuming N or HO gauge:
As an example, my 150' mainline HO layout works very well electrically and is constructed thusly:
These specifications parallel the recommendations given by Allan Gartner. With this arrangement the measured voltage drop is 0.8V on any given power district when maximum load of 5A is applied. In actual train operation this translates to a voltage drop so small it is inconsequential.
This post and those following deal with track wiring on my layout:
http://www.lkorailroad.com/laying-track-part-iv/
Alan
Freelancing the LK&O Railroad
Suppose you are using 12 ga copper for a track power bus. And suppose that you have a 12 foot run. Also suppose that you use 24 ga copper for a track feeder. And suppose that that feeder is 6 inches long. And suppose you are using Code 83 track and soldering a feeder to each rail joiner between alternating pieces of track.
Then.
resistance for the feeder is .0131 ohm
resistance for the bus is .0192 ohm
resistance (maximum) for the rail is .09 ohm
Then the feeder contributes 11% of the resistance, the bus 16% and the rail 73%. These numbers are for only one side of a two-rail system. The resistance will double when accounting for using the other (return) rail. But the ratios will stay the same.
I inserted the word maximum in the rail comment because the resistance will change depending on how far the locomotive is from the solder joint--if it's right at the joint, resistance will approach zero. If you assume that the non-soldered rail joints are as good as solder joints, then the .09 ohm number could reduce to approximately .045. But before you do that, read:
http://www.w8ji.com/track_resistance.htm
Anyway, the effect of using a small SHORT length of feeder wire is minimal. While the need for multiple well-soldered connections to the rails is definitely not.
Soldering EVERY rail joint will likely lead to track problems. Soldering alternate joints and using a feeder at that location is a good move. My recommendation is to solder all joints in curves (for mechanical reasons), none in straights, and attach a feeder to every piece of rail. Including frogs and switch points. But not guard rails.
Ed
(Note, also, that I derived my rail resistance for Code 83 from what appears in the article to be Code 100.)
Thanks to all.
Am I better off splitting the 12 Ga Bus to reach the yard area or use 16 or 18 wire off the bus to reach yard tracks about 2 1/2 ft away from the main line?
A club I use to belong to was wired DC with #24 telephone wire in early 1980's One large room and one small room, all one HO layout.
When we went to DCC, #14 buss and cut all the #24 wires about six to eight inches long. A NCE five amp Power Pro is used. No extra boosters.The DCC amp meter shows about 4.95 amps when the NCE booster trips.
The home made DCC amp meter usually shows about 3.5 amps the last I knew with maybe ten locos. Track voltage about 13.6 volts AC and checked at different points. The complete layout is code 100, handlaid with handlaid turnouts.
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.
gdelmoro Thanks to all. Am I better off splitting the 12 Ga Bus to reach the yard area or use 16 or 18 wire off the bus to reach yard tracks about 2 1/2 ft away from the main line?
For me, I'd stick with one size for bus wire and one for the feeder. So I'd just run the 12 over to the yard area. On my layout, there is a terminal strip for each feeder drop. So the drop is always pretty short.
The reason I'd stick with the 12 is just to minimize inventory. However, if yer in the mood to have a short run of 16, I doubt it's a big deal. That 2 1/2 feet sounds well within reasonable.
7j43kresistance for the feeder is .0131 ohm resistance for the bus is .0192 ohm resistance (maximum) for the rail is .09 ohm
If your gonna get all mathy
...then you need to account for the parallel path that is created by the fact that your locomotive is between two feeders - current comes from the rail in both directions (assuming you don't have gaps between all the feeders). So the resistance for your rail and feeder are each cut in half.
I did.
I discounted the non-soldered railjoiners as unreliable. In that case, they are electrically not-there. So you've got only two pieces of flex track supplied from the middle.
At least, that's what I thought I did. Corrections always appreciated.
Sounds to me that the best solution is to just run the 12 Ga bus under the yard areas. I (being very new to DCC) thought you might not be able to have the bus wire configured like a snake and that it had to go directly under the main lines.
Should I separate the yards with circuit breakers?
Here is a shot of the DC control panel. You can see 2 yards. One is by the care ferry the other is in the middle of the far loop. The layout is 10 x 14https://www.dropbox.com/s/4d1s0up4me28ojy/File%20Nov%2013%2C%207%2027%2022%20AM.jpeg?dl=0
LION uses 12 or 14 ga for the bus of him. (Whatever is in the scrap box!)
LION uses 18 ga for the drops because him has lots of that. Solid is much better than stranded, loose strands can be a female dog. Solid wire really does disappear against the rail, even on the visibal side of the rail, and LION has no porblems putting the drops inside of the guage if that makes installing easier. Thinner wires are more difficult to manage if you have neuropathy or big furry paws.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
gdelmoro Here is a shot of the DC control panel. You can see 2 yards. One is by the care ferry the other is in the middle of the far loop. The layout is 10 x 14https://www.dropbox.com/s/4d1s0up4me28ojy/File%20Nov%2013%2C%207%2027%2022%20AM.jpeg?dl=0
Looking at the picture of the control panel, I'll note that you don't HAVE to rewire the layout IF IF IF you are satisfied with the wiring as it works now. You just have to feed DCC into one of the old throttle inputs, disconnect the other throttle, and throw all the toggles to one direction. That's what I've got here, now. AND. Because of those toggle switches, it makes later troubleshooting potentially easier.
On the other hand, you may be unsatisfied with your present wiring. Which then suggests a re-do for the DCC conversion.
May I ask: Which is it?
Oh, yeah. What are the overall dimensions of the layout? Length by width.
Except that the entire layout is wired with Phone wire
Layout is about 10 x 14'
LION has rewired the layout of him at least 3 times, and I am looking to make some changes on the mower distribution circuits.
Switches, Signals, relays etc are ok on phone wire.
LIONS have lots wires... This panel is only half wired. : ) ROAR
BroadwayLion LION has rewired the layout of him at least 3 times, and I am looking to make some changes on the mower distribution circuits.
gdelmoro Except that the entire layout is wired with Phone wire Layout is about 10 x 14'
Well, then. I guess now's a good time to correct that! On the plus side, it sounds like you already have some of your feeder wires installed . And you certainly won't have to buy any more feeder wire .
You're right about the bus wire configuration: It doesn't really HAVE to be under the individual tracks; it just has to be laid out efficiently to "tag" all the feeder drops.
I don't know about the circuit breaker idea, but it would certainly be a convenience to put in a couple of toggle switches to separate out the two yard bus sections from the main--this for troubleshooting purposes. Or maybe just some terminal strips, whatever it takes to isolate potential future problems. Actually, maybe I'd panel mount three toggle switches, and run a bus for each yard and one for the main from those three switches.
Hi! For HO, feeders of 22 gauge (solid wire) are relatively easy to work with and do the job quite well. There are portions of my layout where I used 20 gauge - probably because I just picked up the wrong spool. But, 20 works great too.
Of course a major factor is the length. I cut all my feeders beforehand to 16 inches, and made sure the buss wires would be within that distance to where the feeders were soldered to the track. And where the 16 inch turned out to be excessively long, well I just cut them back.
On the subject, make sure you have feeders on every siding and turnout leg, as well as every 4-6 feet or so on the mains. DCC is more demanding, and doing the "extra" feeders up front will make your operation a lot smoother for the duration.
Said another way....... I've been on this forum for 14 years, and have yet to see someone have a problem with "too many feeders".
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
Wow. This got off track. Those moving icons come with the last apple update. Phone and iPad