Santa Fe all the way!I assume that a single, 12ga buss for my 80ft "circle" of track will be OK? Basically two 40ft lengths of track with the booster in the middle. Do you think the DCC signal will be ok?
I assume that a single, 12ga buss for my 80ft "circle" of track will be OK?
Basically two 40ft lengths of track with the booster in the middle. Do you think the DCC signal will be ok?
40 feet each way will be fine with 12ga bus. 14ga may be heavy enough but larger never hurts. Use stranded, it's easier to work with and readily available in the electrical section at home centers.
I assume that a single, 12ga buss for my 80ft "circle" of track will be OK?Im running 20ga feeders every 3ft. I will run no more than 4 sound equiped locos at a time. Im using a Prodigy Advance Sq. unit. Im putting the booster unit close the middle of the 80ft. Basically two 40ft lengths of track with the booster in the middle. Do you think the DCC signal will be ok?
chpthrls I'll have a mainline run of apprx. 180'.
If your mainline is an oval then your feeder distance is about 90 feet = Use one booster located at the center (half way point), and send power 45 feet each way. #14 stranded will be fine. (solid is hard to install)
If your layout is a one-way distance your feeder will be 180 feet = Use two boosters located centrally on each half so that each booster sends power 45 feet left and right. #14 will be fine.
Power districts do not increase the distance your feeders can go.
My layout, which was started in 1984, was wired with 12 gauge for a pre DCC system called Dynatrol. The layout had 4 main buss feeds, none of which exceeded 50 ft, and the system was set in a central location to insure lower lengths for the main buss. In 2000 I switched to NCE DCC, simply detached the Dynatrol, installed the NCE command station, with four boosters for four power districts and have never had a problem with feed or power in any way. the layout, by the way, is three decks, with the middle deck having two different boosters and the mainline is split (insulated) for protection. Of course the boosters are isolated from each other.
My power buss is e stranded 12 gauge, I used suitcase connectors, the track feeds are 18 gauge from the bus to the track, and the railroad runs great. I am no electrician, but had good advice when I set it up from other modelers who had walked the same path.
Bob
Allegheny2-6-6-6 mfm37 To carry 12 - 14 volts 180 feet with less than 5% drop, #0 wire will be needed. He'll need a torch to solder track feeders. LOL I can see the layout collapsing under the weight of the buss wires, but he won't have any voltage drop.
mfm37 To carry 12 - 14 volts 180 feet with less than 5% drop, #0 wire will be needed. He'll need a torch to solder track feeders.
To carry 12 - 14 volts 180 feet with less than 5% drop, #0 wire will be needed. He'll need a torch to solder track feeders.
LOL I can see the layout collapsing under the weight of the buss wires, but he won't have any voltage drop.
He could always go with #0000 and the bus wire could double as legs on the layout. It would be sturdy.
Engineer Jeff NS Nut Visit my layout at: http://www.thebinks.com/trains/
rrinker Now you see why I use STRANDED wire for the bus. #12 stranded is not hard to pull. I don;t understand the tendency towards solid - that IS hard to work with. It might be fine pulling up a nice straight wall when doing house wiring, but trying to thread it under model railroad benchwork is a true pain. If you get it for free as leftovers from a house job, the extra pain might be worth it to save the wire cost, but if you are buying new, buy stranded - it's much easier to handle. Bending solid wire back and forth is asking for a weak spot or a break. I use solid for my feeders, no loose strands around the track, and they simply go straight down through holes to underneath the layout - they aren't moved or pulled, so the stiffness of the wire becomes an asset. --Randy
Now you see why I use STRANDED wire for the bus. #12 stranded is not hard to pull. I don;t understand the tendency towards solid - that IS hard to work with. It might be fine pulling up a nice straight wall when doing house wiring, but trying to thread it under model railroad benchwork is a true pain. If you get it for free as leftovers from a house job, the extra pain might be worth it to save the wire cost, but if you are buying new, buy stranded - it's much easier to handle. Bending solid wire back and forth is asking for a weak spot or a break.
I use solid for my feeders, no loose strands around the track, and they simply go straight down through holes to underneath the layout - they aren't moved or pulled, so the stiffness of the wire becomes an asset.
--Randy
I use the same, stranded bus wire and solid feeders. I concur that solid feeders are much easier to solder and stranded bus wire is much easier to run.
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
The other item I always like to point out in these typs of discussions is that even if there is some voltage drop over the length of a bus run, the impact may not necessarily be noticable for two reasons. First, most of us do not run our trains at full throttle so if (for example) at one end of the bus the decoder can deliver a full 12V to the motor and at the other it can only deliver 11, that may be perfectly fine. Remember that the rectified voltage that the decoder pulls off the buss is not the same as what is delivered to the motor. It is proportionally less based upon the throttle setting. Second, folks often talk about a full 5A load to calculate the voltage drop. That works if the full 5A load is at the other end of the bus from the booster. In the real world, the load is likely spread across the buss, if you are running multiple trains. Thus the voltage drop at the far end will not be as great as what is calculated. I've mu'd 7 modern sound locomotives and not been able to pull anywhere close to 5A.
Vail and Southwestern RRTexas Zepherchpthrls my question is whether 14AWG is large enough gauge to use as the main buss from the booster? Think about it, 14 gauge wire is plenty enough to deliver 12 amps at 100VAC in a normal house circuit. I think it will be large enough to deliver 5 amps at 17.5VDCC. This is irrelevant. The reason for limitation in a household circuit is heat. This issue for a DCC bus is voltage drop. A 100 foot run of 14 gauge wire has a resistance of a little over .25 Ohm. So, 180 feet out and back is pushing an Ohm. If one was to actually draw 5A at the end of that run, there would be a 5V drop at the destination, just due to the wire. Starting at 14V, that's pretty significant, probably enough that things are not going to work right. What generally saves us, and causes people to correctly say that it will usually work, is that we very rarely, if ever draw the maximum current at the end of the line. More likely to have a couple locos out there, drawing a total of 1/4A, with a voltage drop of 1/4V, which will work fine. So, the facts are that #14 will almost certainly work fine, but #12 is the more robust solution for the "worst case" scenario. Take your pick. (Actually, for a run that long #12 might not really be enough, an additional booster might be required, really.)In a household circuit, you also have the voltage drop. If you draw 15A through a 14 gauge circuit, a long way from the panel, you might find a drop of 15V. And whatever you have on the end might not work right. But your house won't burn down because of it, which is the only concern of the Electrical Code. It's based on safety, no performance. In DCC, we run into performnance issues before safety.
Texas Zepherchpthrls my question is whether 14AWG is large enough gauge to use as the main buss from the booster? Think about it, 14 gauge wire is plenty enough to deliver 12 amps at 100VAC in a normal house circuit. I think it will be large enough to deliver 5 amps at 17.5VDCC.
chpthrls my question is whether 14AWG is large enough gauge to use as the main buss from the booster?
This is irrelevant. The reason for limitation in a household circuit is heat. This issue for a DCC bus is voltage drop. A 100 foot run of 14 gauge wire has a resistance of a little over .25 Ohm. So, 180 feet out and back is pushing an Ohm. If one was to actually draw 5A at the end of that run, there would be a 5V drop at the destination, just due to the wire. Starting at 14V, that's pretty significant, probably enough that things are not going to work right. What generally saves us, and causes people to correctly say that it will usually work, is that we very rarely, if ever draw the maximum current at the end of the line. More likely to have a couple locos out there, drawing a total of 1/4A, with a voltage drop of 1/4V, which will work fine. So, the facts are that #14 will almost certainly work fine, but #12 is the more robust solution for the "worst case" scenario. Take your pick. (Actually, for a run that long #12 might not really be enough, an additional booster might be required, really.)
In a household circuit, you also have the voltage drop. If you draw 15A through a 14 gauge circuit, a long way from the panel, you might find a drop of 15V. And whatever you have on the end might not work right. But your house won't burn down because of it, which is the only concern of the Electrical Code. It's based on safety, no performance. In DCC, we run into performnance issues before safety.
Some people just have to spout off to show how much they know than everyone else.
Personally, I really hate 12 gauge wire just because it is so big and hard to work with.
Thanks for all the replies. I think I'll stay with the 12AWG for the buss. In way of clarification, I'm installing the CVP "Easy DCC" system along with their Zoneshare unit. It divides the layout into four circuit protected zones with one with an auto-reverse for the wye on my layout. I'm modeling in HO and as a single operator (I have no friends), only will be running two to three trains at once. The 12 gauge wire may be "overkill", but better safe than sorry. Thanks again for the information guys. Gerry S.
Jeff But it's a dry heat!
DO not mix up the fact that #14 is good for a 15 amp AC house circuit with the use as DCC track wiring at 14 volts. It doesn't translate. Look at the specs of AC household appliances. Usuaully the range is 100-130 volts. So a couple of volts drop from the 120VAC input is no big deal - it's a small percentage and still within the rating of the device being connected. 180' run of #12 at 120VAC with a 10 amp load plugged in at the end is still a bit over 113 volts get to the device.
A 1/2 volt drop in one section of track might be the same percentage loss, but a half volt drop is enough to cause a visible speed difference in an HO loco. 360' of #12(180 out and back - mus thave a complete circuit) is goign to be closer to 1 volt (0.7) (with a 1 amp load), definitely noticeable.#14 same conditions would be a 1.1 volt drop.
Quite frankly, for a 180 foot one way run you will need a second booster. Voltage drop which leads to diminished signal is the reason for using larger wire.
Using a 5 amp load, 120 volts in your house will drop 3.89% at 180 feet leaving 115 volts to light your lamps.
That same 5 amp load at 12 volts on a model railroad will drop 38.9% at 180 feet leaving just over 7 volts to run a train.
We tested wire size and voltage drop for NTRAK several years ago. We found that 12 ga wire would carry the DCC signal 100 feet before the signal would begin to fail. We settled on 80 feet one way as a maximum length for one way DCC - IF 12 ga wire was in use.
Martin Myers
You can use house wire which is sold in smaller quantities.
The issue as I understand it is signal loss and shorting detection. Both of these are dependent on how long the wire from the booster is and how big the wire is. If your 180" is a straight line and you put the booster in the middle then you have 2 runs 90 feet long. If your 180' is an oval and you put your booster in the middle you have 4 runs 45 feet long. And so forth. AWG 12 is better than 14, but 14 works okay for shorter runs.
Check this site http://www.wiringfordcc.com/ for more info.
Enjoy
Paul
I made the mistake of using #12 where #14 would have worked fine. I guess a little overkill won't hurt. Unless your building a very large railroad and even at that I can't imagine a great amount of voltage drop occurring as larger pikes require power boosters. All that aside save yourself some money and buy one roll of black wire and ask someone in the department for colored electricians tape. Electricians don't but different colored rolls of wire it's just not cost effective so the wrap the ends with different colored tape signifying which leg is witch. Just put a wrap of colored tape every couple of feet so if you need to make a connection from one of your power drops you'll know which wire to hook it to. Another little thing you should do to keep things uniform is pick two colors for your power buss I choose red & white which happen to coincide with the colors on my power drops. red always closest to you is the way I wire everything. It will pay off down the road when you have a short some place.
by doing so you just saved half the money you were going to spend on wire.
One thing you need to remember #14 AWG is not the same as #14 house wire. House wire is solid wire where #14AWg can be either solid or stranded wire. I choose stranded wire as it's a lot easier to work with then solid core wire. I think if you compare prices you won't find a great saving in using house wire definitely not worth the hassle.
See the recent thread on DCC "ringing".
Hi Gerry,
Is your run 180 feet out and 180 feet back or a loop with a total length of 180 feet?
How many locomotives will you be running at one time in one zone? Will they have sound? All of these factors make a difference.
14 ga. wire has a specific resistance of 2.525 ohms per 1000 feet or about .5 ohms for 200 feet
12 ga. wire has a specific resistance of 1.588 ohms per 1000 feet or about .32 ohms for 200 feet
These vary somewhat with temperature but not enough to worry about for our purposes. Ohm's law states E=I*R or voltage drop equals current flow multiplied by resistance. For example a one ampere locomotive will drop half a volt on a 14ga. bus or 1/3 of a volt on a 12ga. bus 200 feet long.
Double the current draw (the number of identical locomotives) and the voltage drop is also doubled. You need to find the total maximum bus length (out plus in), the number of locos and the average current draw. Then you decide on how much voltage drop you cam live with. I suggest under 1 volt.
A good "quick and dirty test" is to run a temporary bus to a section of track and drop a quarter across the track. If the circuit breaker trips or the series tail light bulb lights to full brightness the bus is large enough.
Sorry for the non answer but we need more detailed information. Besides "teach a man to fish ..."
Karl
The mind is like a parachute. It works better when it's open. www.stremy.net
14 gauge is good enough. Do you need the full spool? You can buy it by the foot. I used 14 awg stranded on my N layout because I had it left over from my job. My club is also using it on our permanent and modular HO layouts.
I have a question concerning buss wire gauge. I am in the process of converting from DC block control to DCC. I priced bulk wire at the local big box store today, and there is a $15.00 difference between 12AWG stranded and 14AWG (500' spools). Soooo, my question is whether 14AWG is large enough gauge to use as the main buss from the booster? I'll have a mainline run of apprx. 180'. I'll spend the $30.00 if necessary, but a penny earned is a penny saved. Thanks Gerry S.