Bus wire

I just recently did mine, I ran the wires around the layout but, did not hook up the ends to the transformer. I have two loops of track, so I ran two hot wires for the loops and they share one common ground wire. Hope this helps you

In conventional mode, there's no electrical reason not to reconnect a loop to the transformer. However, if you've got a loop, why not split the bus at the transformer, run it in both directions with each end as far away from the transformer as possible. This would eliminate the small effect of resistance in the bus wire to a minimum throughout the layout. Electricity takes the shortest path that it can find.

For TMCC, Legacy, and DCS, I'm not sure if there are any problems with running a loop back to the transformer. There may be issues with reflection of the digital signals. Other bus systems that carry digital information use pull-up or pull-down resistors to terminate the bus and reduce the effects of reflection.

No, don't connect it to the transformer again. The loop is the red out and the black return. I have begun to create an isolated joint in even the simplest small ovals to prevent the track from looping back on itself.

No electrical reason, I just don't get any problems, so I do it this way.

It seems command control might not like a "loop" though some folks do it.

As stated, two straight shots of equal length are best for a number of reasons.

The only advantage of a loop is if you're using too light a wire it pretty much doubles it; not really the "right" way to handle things, but an effective workaround

All,

Not that I would do it, there is not a problem of running your Neutral (AC term) or ground (a misnomer with AC) out and then back to the same lug on your transformer as it is the "same potential". Likewise with your Hot (AC Term) lead. Now this is for Lionel TMCC/Legacy setups. I am not into DCS but they tend to talk a spider leg approach and not a single buss (as opposed to a bus which is a multi passenger vehicle) around the layout. 

Regarding running two Busses in opposite direction and terminating as I describe below, I am not sure of the merit.  Running electricity through the track has the limitations of resistance through the track connectors and other forms of resistance due to the track.  When you have resistance you have a voltage drop because of the inherent resistance of the track. Hence when you connect your power to the track near the transformer, your Locomotive runs fine at the point of power entrance and runs very slowly at the extreme distances from the power input point. Yes a buss wire also has resistance but it is infinitely small without a lecture on the formulae for calculation.  But needles to say the gauge of the wire has a great deal to do with resistance of the wire. For my buss wires, both Hot and Nuetral, I use 14 gauge stranded. If you want less voltage drop then you can use 12 gauge but the affect of doing so unless you have a huge layout is of limited return for the additional cost of the wire. 

Now as I said I don't think I would run it back to the same lug on the transformer. I ran my loop and then applied a crimped lug to the end and put a screw through the lug into wood just so it was not dangling.

Sorry for the verbose answer but I thought the extra verbiage was necessary based on some of the replies I read. 

According to the "Telecom Dictionary" of terms from "Higgins International" :

Bus - One or more conductors or optical fibers that serve as a common connection for a group of related devices.

And the NEC (National Electric Code) uses the term "bus" throughout their documentation.

There was (or is) a company named "Bussman" that manufactured fuses. But I've seen both "bus" and "buss" used in electrical discussions. It seems to me that either one may be used without causing any real confusion. Just sayin'!

Ok, I may relent on the spelling as the definition to Buss refers to kissing (huh).  But of course the first few definitions of "Bus" refers to the vehicle, maybe it is like "Grey" and "Gray". 

Ok, I may relent on the spelling as the definition to Buss refers to kissing (huh).  But of course the first few definitions of "Bus" refers to the vehicle, maybe it is like "Grey" and "Gray". 

The purpose of bus wire around the layout is to distribute power to the track. To rely on the track alone to provide a good connection is a gamble because, as Jim points out, there are unreliable track connectors, pins, and other structural reasons to doubt the integrity of the circuit. The bus wire and the drop wires connected to the track every few feet ensures that the power gets distributed more evenly to all sections of the layout.

To reconnect the bus wires to the transformer after going around in a loop only affects the path that the power takes to get to where it is needed (electricity takes the shortest path). It does this on its own and is not a real concern for the bus wire distribution technique.

I have positive and negative leads from my 1960s ZW transformer to continuous negative and positive bus wires. No problems and TMCC works fine. 

Thank you guy`s, i appreciate all the answers, will try both ways and see which one works best,merry christmas to you all

I think we got into buss from Bussman fuses, that was the abbreviation back in the day... now Cooper-Bussman I think.

Star wiring or home run wiring or spider wiring (I like that descriptive word) seems best all around with DCS.  One never knows what the future holds, one day you may want to feature DCS.  So, because of that reason alone I "spider " wire all layouts.  Of course each fed block is insulated from one another.

Another thing about star wiring that can be helpful, I have a toggle on every star feed for three reasons.

1.- For short detection on a larger layout one can shut down the entire pike then bring up each star run one at  time so as to find the culprit.

2.- Most folks have at least a few conventional engines so the ability to shut down a district anywhere is an option.

3.- Storing an command engine on a dead track will not cause run a way time usage.

When using a modest loop or two a simple two wire connection is fine.  Even on a small 2 wire feed loop, if you connect one wire at the twelve o'clock position and the other wire at the 6 o'clock position, conventional train speed will remain somewhat consistent.

Del City has decent wire pricing and they carry it in 12 colors.        Multi colored wires help in busy panels:

oh, one more question, what is the best gauge wire to use for the bus and feeders

My thoughts on bus/Buss (who's got the buses) is 14 gauge stranded on the hot side and 12 gauge stranded on the neutral. The reason for the difference is the concept of a common neutral. Your switches, accessories, etc all have their own hot so there is not the same power through your hots but using the common neutral all the neutral power is returning using that same wire. Note: for my accessories, switches, etc I use 18, 20 or what ever is handy in that realm of gauge. Some I have seen on this forum go as low as 16 gauge

As far as feeders of your hot, I again use what is available around the basement and what connectors (again some on the forum swear by soldering connection), I have available. The last few feeders I ran, I used 14 gauge because I had it and I have a big supply of Blue connectors. What others use is usually in the 16 to 18 gauge range. I have also seen member use 20 or 22 gauge but that is as high as it gets and is tipping the edge. 

My thoughts on bus/Buss (who's got the buses) is 14 gauge stranded on the hot side and 12 gauge stranded on the neutral. The reason for the difference is the concept of a common neutral. Your switches, accessories, etc all have their own hot so there is not the same power through your hots but using the common neutral all the neutral power is returning using that same wire. Note: for my accessories, switches, etc I use 18, 20 or what ever is handy in that realm of gauge. Some I have seen on this forum go as low as 16 gauge

As far as feeders of your hot, I again use what is available around the basement and what connectors (again some on the forum swear by soldering connection), I have available. The last few feeders I ran, I used 14 gauge because I had it and I have a big supply of Blue connectors. What others use is usually in the 16 to 18 gauge range. I have also seen member use 20 or 22 gauge but that is as high as it gets and is tipping the edge. 

    I run some pre+ post war which use more amps., and I like just a tad of overkill. So I always use 12g. 14g is ok for most though.

   On rare occasion, there can be issues with way to big a wire size. You will likely never experience it though. A larger gauge is usually safer should something catastrophic occur. Red hot, melted insualtion, etc. is less likely if the wire size can handle the max. amps a direct short might drag across it.

     E.g. if you use 12g everywhere on 5a max output transormer, that wire can handle a direct short for a much longer period than 14 or 16g, and will have only a negligible loss in delivery from being oversize. There is also a very slight danger in that should the transformer "blow up" (just doest relly every happen) you could get 12g delivering full household ac amps on a sturdy 12g line where a lighter one would not deliver big amps  without burning to failure (just an example... which scene would you feel more confident facing? I like system wire overkill because that's generally the weaker link imo..  Fusing becomes more imperative with more closely matched wire too.

We mostly don't go overkill as it can be a cost issue.

  Using a larger gauge on the return leg is really usually more of a dc thing for ensuring ground (it's along the lines of dc vs ac; "directional delivery" on dc, while ac flows both directions) however a gauge oversize on common could be useful with ac in the future because when you run something new/small, you can just run one new hot wire then grab the common from "anywhere". (till you have equaled the larger wire's amp rating on total " common returns" anyhow)

Buy various colors. Nothing is worse for trouble shooting or new additions later on, than a whole nest of the same color wires. It doesn't need to be a huge variety, just enough for different circuits to be recognized easier. 5 years from now you likely won't reacall which of the 5 red wires feeds the the shack or which feeds the block signals so now you get to test it all again before work can even start.

 Ideally I run black or brown on common (or black/brwn stripe) Red and white on hots, blue on lighting, stripes after controls/switches etc.; but usually what's on hand overides ideal, so buy variety now, lol.                 (note, one in a million you work on something from overseas, they often use different common color codes that we are used to so i.e., never trust color alone)

Going back to one leg being larger in size; in most three rail set ups the track itself is already twice as heavy on the common from 2 outside rails vs the lone center rail. It doesn't deliver as easily as wire, but you could take that into consideration in your delivery using say 12g for a short run right to track, then 14g hot and 16g common and still be heavy and balanced enough to handle any OCD impressions of it all.    

  It won't likely affect you, but related in theory: there are two types of tubular 0-27 track pins; solid-early/better and hollow- made later. The hollow rust internally weakening amps delivery over time. The commons rails have two pins so delivery is x2 even if weak. The hollow center pins however can get red hot if corroded inside. Simply switching the center pin to a solid version improves it's capabilty dramatically. Adding one solid pin out of the 2 commons is all that's really needed should those happen be very weak too.

(to test and old nasty pin for solid or hollow, try to crush it with pliers. Solid cant be crushed and can be cleaned up for reuse. But nasty looking hollows ones should be tossed. So i.e., there is no loss crushing a nasty hollow one

Buss wires on CL&W are 14ga with 16ga drops from the track, with one hot feed per block of track.  Tied both common rails together.

System handles loads of 10 amps at 24 volts without any problems from the pair of Z-4000 transformers.

Lighting and switch motor power is separate powered by a ROW transformer.

Wired like Barry suggested in his book, star-type pattern, the book is worth purchasing.

Kerrigan posted:

Buss wires on CL&W are 14ga with 16ga drops from the track, with one hot feed per block of track.  Tied both common rails together.

System handles loads of 10 amps at 24 volts without any problems from the pair of Z-4000 transformers.

Lighting and switch motor power is separate powered by a ROW transformer.

Wired like Barry suggested in his book, star-type pattern, the book is worth purchasing.

 

Who is Barry, and what is the name of his book? Thanks.

I don't know if Barry has a last name, but on this forum he certainly doesn't need one. It is essentially the last word on DCS.

John H posted:

I don't know if Barry has a last name, but on this forum he certainly doesn't need one. It is essentially the last word on DCS.

Thank ye kindly good sir!

I'm guessing it would be the "Broskowitz" shown at the bottom right of the picture you posted.

I neglected to mention that it is available in softcover and digital editions on the MTH site online store.

 I didn't think the O.P. was running modern units.

 Please note some suggestions for lighter wire are sometimes being made by folks running mostly modern trains.

Kerrigan I have to ask. You have ten amps availible, or you draw ten amps across one line?

 Modern can motor trains use way less amps. than a pre or postwar open frame motor type. A 90w transformer is barely enough for operating some bigger PW at all. I have had three engines that will pull 3-alps3.5a normally, peaking at 5.5a on a loaded start up(peak, not continuous). One 4-6-4 can't pull more than a few cars or it will stall on the 15v90w 1033. Give it 10-20 more watts and it flys well enough to jump.

   Do the math for two of these PW trains running on the same rails (block control) and tell me you want to even touch the smaller gauge wire after an hour.... while I get the burn cream and a band aid for your finger. I didn't always use 12g. I didn't like how hot my wiring got with 16-20g

   If I'm not mistaken, I think Tom T likely has the most long wire pull experience with wire length/ gauge/watt tables locked into memory, but the mininum size for length at x volts, x amps, info is an actual common standard, you'll find it all over if you seach for wiring tables. (note solid wire also needs a lesser gauge because of air gaps in stranded wire.)