What wire gauge or size is best suitable for track power feeding?
alloboard What wire gauge or size is best suitable for track power feeding?
Depending on how big the layout is, and how complicated it is it could be any thing from 18 ga to 12 ga.
The rule of thumb is 14ga for bus wires, and 22-18 ga for track feeders. Some say 22 is adequate, be that as it may, the LION uses 18 ga. LION runs 8 to 12 trains at once.
If it is a small layout than 18 ga is good enough for everything.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Since LION just confused you, AWG-22 or AWG-20 will be good for track feeders for your situation and layout.
AWG-12 or AWG-14 would be used for the Power Bus that the feeders connect to.
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.
15 amp 110 volt house wiring is only awg14. For what possible reason would you need awg12 for a 5 amp 14 volt bus under your layout?
Dave
Lackawanna Route of the Phoebe Snow
Phoebe Vet 15 amp 110 volt house wiring is only awg14. For what possible reason would you need awg12 for a 5 amp 14 volt bus under your layout?
That seems to be what is recommended for DCC. LION does not use DCC, but his power supply does put out 15 amps. LION plans to run up to 12 trains at one time, half with dual power cars. I really have not seen my ammeter reach 3 Amps, but then so far I have only run 5 trains at one time. Other train sets are waiting for modification.
Others have argued the point with me, but the LION still maintains that you loose your lower speeds with inadequate wire. The LION does have 1000' of track.
That's a good question. Two factors come into play, both relating to the resistivity of the wire. One is generated heat (which is minimal with the right gauge), the other is voltage "drop" over the length of the wire. For example, a loss of voltage to the load of 6 volts is hardly noticeable at 120 volts but is catastrophic at 12 volts. (50% vs 5%).
This table might be helpful.
The mind is like a parachute. It works better when it's open. www.stremy.net
Why would you use #12 wire? Two words: Voltage Drop
Yes, house wiring uses #14 for 15 amp circuits. But the nominal power at the box is 120V, and it's sort of who cares if there is a 5 or even 10 volt drop, most things run on 105-125V - check the plate on various electrical appliances.
Now, if you only start with 14 volts and drop a volt - that's actually enough to notice, say you had 2 sections of the layout with gaps in the rails, one side was powered at 14 volts, the other at 13 - you'd see that. You want to really keep to a half volt or less drop, so if you take a look at the wiring resistence per foot, and say you have a 50-60 foot run, that's 100-120 feet of wire (need a complete circuit) and even say there is just one double-headed train drawing 1.5 amps. #14 would just make it with a .455 volt drop. #16 though, would be .724 volt drop. If you allow more power, say the section feeds an area where more than one train runs, and 3 amps are drawn. #14 is now dropping .91 volt, #16 would be 1.45 volts - defintiel a noticeable drop in speed as the trains reach the far end of that feed.
If you bus lines are in the 20 foot range or smaller, it won't matter too much. #16 would be fine even.
As for feeders for HO, I use #20 because they have nice spools in red and white at Home Depot, it's 2 conductor but loosly twisted so easy to take apart. This matches my red and white bus wires.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Then I must be using super conducting wire. I have a 60 foot bus of awg 16 stranded wire. The wire is much longer than even that because it is twisted. With 10 locos, 3 with sound, and 12 lighted cars on it, the voltage is 14.0 at the place where the command station connects, and 13.7 volts at the far end of the bus.
Phoebe Vet Then I must be using super conducting wire. I have a 60 foot bus of awg 16 stranded wire. The wire is much longer than even that because it is twisted. With 10 locos, 3 with sound, and 12 lighted cars on it, the voltage is 14.0 at the place where the command station connects, and 13.7 volts at the far end of the bus.
As noted before the gauge used is a function of resistance and not current carrying capacity.
While your trains will run using 16 gauge wire at 60 feet you lose a couple of things doing so.
The biggest one is short circuit protection. Because of the resistance in the wire, when using thinner wire there are times when a short will not be detected. The reason is that the extra resistance in the thinner wire drops enough to prevent a true short at the source. When this happens the command station continues to pump out current and the potential for fried componts results. I've seen wheel sets melt and decoders lose programming. Others have reported damaged decoders.
A good test is to put a quarter at the farthest point from the power source. The breaker should trip immediately. If it doesn't you effectively have no short circuit protection.
At the club we had a couple sections up to 50 feet away from a booster with 16 guage wire and had lots of troubles. we re-located the boosters to the half way point of those sections and the problems cleared.
Springfield PA
By the way when you measure voltage drop in a circuit you place the load at the farthest point. Having the loco's closer to the source and measuring at the farthest point is not an accurate reading.
It trips immediately, even at the far end of the bus.
Well your numbers don't add up with what you're reading.
A 60 foot bus is 120 linear feet.(out and back) With 10 loco's and lighted cars you should have seen at least triple the voltage drop you noted earlier. Here's a voltage drop calculator.
http://www.stealth316.com/2-wire-resistance.htm
I guess your voltage drop calculator and my multimeter didn't go to the same school.
Even the triple the drop that you predicted would still be less than a volt.
As I have related here in the past, I was persuaded to add an off-layout staging 'yard' of sorts four years ago on my previous layout. I didn't want a lot of bother, except I had to create a 5' bridge to run from the layout to the staging. I fed the entire yard from a pair of feeders that were soldered to the spur track at the end of which was this bridge I mention. So, through 3' of 22 gauge single filament copper wire feeding the spur, the power had to run further to the joiners, across them and the 5' bridge, and then power six turnouts and about 30 linear feet of parking track. Sometimes a short was detected, but not always, by the DB150 base station. However, the power was sufficient that I never had the slightest problem getting the engines to respond to commands and to run up to the layout if I wanted them to.
What I take from this is that the tables provided by the industry are highly conservative, and at least one site makes a point of this. Yes, there will be significant voltage reductions with sub-standard transmission material over distance, and yes you run a risk at some point further along of not being able to save decoders during a hard short because the signal-to-noise ratio is so bad out there that the detection circuitry just won't detect the fault. However, unless you are running serious loads, say 5-8 amps through 22 gauge feeders, even for extended distances, you are unlikely to experience a problem. By extended, it would be in the range of 20'. You could feed a mine spur with two 20' leads of 22 gauge copper wire, but don't expect your short management circuitry to work reliably. The decoders and motors themselves, though, will work just fine. Did it often.
Just FYI. The tables provided by the industry don't lean either way. They are actual readings and math that doesn't change.
All we want to do is give the OP the answer before he/she begins installation. While some have had luck running lower gauge wire, others including myself several times, have seen equipment damage and program loss with decoders.
Either way my recommendation to the OP is to use the largest sized feeders he can afford. The cost for the amount of wire we're talking isn't that much (less than the cost of a good piece of rolling stock in most cases), and will put you on the safe side at a minimum.
Somethign to consider, if that 60 foot bus is tapped every few feed for feeders to teh rails above, you ALSO have the rail as a parallel condcuter to teh bus wire, increasing the effective wire size and reducing the resistence. Until some rail joiners start to fail - there will be power because you ran a bus and used plenty of feeders but the track will no longer be in parallel. However it's unlikely that ALL rail joiners will fail, which means you'll end up with a bus of part #16 + and sections of #16 alone. The end result is you will see less drop than #16 alone. The bad way for this to be done would be if you used a cetralize circuit breaker or block detector, and then ran #16 60+ feet out to the isolated section of track for that breaker or detector, then you would get the voltage drop under load per the tables.