Of all the commercial breakers I see on the market, they ONLY break one leg of the input when there is an overload.
Personal experience has told me this is not enough when you have:
1) The possibility of misfed wires with other power sources (ie: Switch machine power)
2) More than one booster and you don't properly isolate districts.
You can get a backfeed on the leg that is not cut off. This can send a lot of voltage or amperage through your booster. Your booster would take it till it burned up. Very few boosters look for backfeed current.
The only reasonable way to protect against this problem with large layouts is
1) Wire a 1157 bulb to the leg that is not on the breaker to limit amps.
OR
2) Buy something like a PSX-AR which has breakers on both legs...but cost a small fortune.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
If you are Electrically challenged, you need to LEARN so you don't make those mistakes. It is also called ATTENTION TO DETAIL.
If you think that you can just throw layout wiring together and it will all work OK, you are sadly mistaken.
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.
gandydancer19 If you are Electrically challenged, you need to LEARN so you don't make those mistakes. It is also called ATTENTION TO DETAIL. If you think that you can just throw layout wiring together and it will all work OK, you are sadly mistaken.
I'm far from electrically challenged. I'm an engineer who used to work on satellites. It can happen to anybody with enough wires.
Digitrax PM42 breaks both output wires.
It's called QUALITY CONTROL !
If you don't practice it - then you will find all sorts of new junk pieces once the black smoke has been let out!
It seems that we never have the time to do it right - but always find the time to fix it again and again!
Having learned the hard way!
BOB H - Clarion, PA
But I thought DCC only required two wires - how could anybody mess that up?
"It seems that we never have the time to do it right - but always find the time to fix it again and again!"
Bob, I was an electrical construction project manager for years - I use to repeat that phrase over and over.
Seems this DCC thing is not really "just two wires" after all, is it?
Sheldon
ATLANTIC CENTRAL But I thought DCC only required two wires - how could anybody mess that up? "It seems that we never have the time to do it right - but always find the time to fix it again and again!" Bob, I was an electrical construction project manager for years - I use to repeat that phrase over and over. Seems this DCC thing is not really "just two wires" after all, is it? Sheldon
Depends on the layout size. a very small layout like mine CAN run DCC with "just two wires connected", and it did for awhile. I added two sets of feeders on teh opposite side of the layout just cuz better feeding to the far side.
-G .
Just my thoughts, ideas, opinions and experiences. Others may vary.
HO and N Scale.
After long and careful thought, they have convinced me. I have come to the conclusion that they are right. The aliens did it.
Don.
Being a simple man I am. Have you looked at the DCC specialties OG there is also an OG-AR. Tony's has the OG for $25. Sometimes we tend to over complicate simple things like 2 wires.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Martin beat me to it, the PM-42 does break both wires. Sometimes there is an advantage to those 'old fashioned' mechanical contacts. Mine works great and doesn;t seem to have problems with my sound locos, both of which are Loksound. Oh and an old Soundtraxx LC. The lC has no keep-alive, and the Loksounds have always programmed just fine with no special boosters or anything. I stay away fromt he brand that requires a booster unless you do POM. I don;t care how good the sound quality is, the program issue is a design flaw plain and simply, and others have already solved it.
Unless your layout is so large and supports runnign more locos than you can power with a single booster, you really CAN get away with "two wires" You still need feeders, track is no better a conductor of DCC power than it is of DC. A 100 foot strtch of DC track with just two wires at one end isn;t going to work very well either. Breakers - NOT required. A layout will work just fine without them - but when someone makes a bonehead move and shorts the track, the entire layout will stop if no extra breakers are used.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
ATLANTIC CENTRAL Seems this DCC thing is not really "just two wires" after all, is it? Sheldon
Currently, mine is. So maybe it is, really.
I'm trying to model 1956, not live in it.
Two wires are all that is required for DCC. Success depends on how inadequate the DC wiring is that's connected to the two wires.
mfm37 Two wires are all that is required for DCC. Success depends on how inadequate the DC wiring is that's connected to the two wires.
I wish I could make some sense of this reply, but I just don't get it.
Sheldon,
I really do respect your experience and skills, but you just kind of stuck your foot in your mouth. All the excess wires came from a layout that was being converted from DC->DCC.
Some relays had as many as 24 wires coming off them. All of this old wiring was to maintain correct polarity when crossing from one throttle power district to another. A lot of if was for block occupancy sensor wires. There was also wire arrays for yard turnouts. (Each running off 25VDC) With DCC we could remove the old occupancy detection as the breaker also provided occupancy feedback.
Over half the wires were removed in the conversion I would estimate. More are going to be cut soon.
cmrproducts It's called QUALITY CONTROL ! If you don't practice it - then you will find all sorts of new junk pieces once the black smoke has been let out! It seems that we never have the time to do it right - but always find the time to fix it again and again!
Well the problem being is its a very OLD DC layout. And over the years its been patched and patched again with no consistancy on wiring colors or types. (I guess you make due with what help, funds and equipment are available.) It was ingenious, but over the years it just became a maintenance nightmare.
BTW: I love CMR's buildings!
mfm37 Digitrax PM42 breaks both output wires.
Thanks for the tip Martin
DigitalGriffin ATLANTIC CENTRAL: But I thought DCC only required two wires - how could anybody mess that up? "It seems that we never have the time to do it right - but always find the time to fix it again and again!" Bob, I was an electrical construction project manager for years - I use to repeat that phrase over and over. Seems this DCC thing is not really "just two wires" after all, is it? Sheldon Sheldon, I really do respect your experience and skills, but you just kind of stuck your foot in your mouth. All the excess wires came from a layout that was being converted from DC->DCC. Some relays had as many as 24 wires coming off them. All of this old wiring was to maintain correct polarity when crossing from one throttle power district to another. A lot of if was for block occupancy sensor wires. There was also wire arrays for yard turnouts. (Each running off 25VDC) With DCC we could remove the old occupancy detection as the breaker also provided occupancy feedback. Over half the wires were removed in the conversion I would estimate. More are going to be cut soon.
ATLANTIC CENTRAL: But I thought DCC only required two wires - how could anybody mess that up? "It seems that we never have the time to do it right - but always find the time to fix it again and again!" Bob, I was an electrical construction project manager for years - I use to repeat that phrase over and over. Seems this DCC thing is not really "just two wires" after all, is it? Sheldon
Don, respectfully, my orginal post was just a little fun, since every time I talk about DC on this forum someone ALLWAYS tells me how DCC is just two wires.
Second, also repectfully, I understand you may be dealing with a club, or some other situation where many hands and/or lack of planning/docmentation may have been the order of the day, but as a retired electrical design draftsman and electrician, who 30 years ago installed some of the first computer based machinery control systems, and designed complex relay machinery controls before that, there is in my mind little excuse for poor wiring practice or poor documention.
Third, also respectfully, faced with a poorly documented DC system of the nature you discribe, for me the conversion to DCC would have required complete reworking - not "patching in". Last year I installed my walk around advanced cab control system using Aristo wireless throttles on a friends exsisting DC layout that had rotary cab selectors and teathered cabs. We gutted it all except for the drops from the track and started over.
Fourth, also respectfully, this type of thing is exactly why I choose not to be involved in formal clubs and choose not to accept help from others on my home layout.
But my sarcasm still stands because, having been involved in the wiring of several large DCC layouts, I know for a fact anything more than a 4x8 needs more than the famously advertised "two wires", especally if you have 40 sound equiped locos like a few of my friends.
And then, even with DCC, a whole new infrastructure for signaling.
This was a test, Randy passed. He obviously just blew off my comment as the little fun that it was.
Those responding to me either didn't get it, or now know how I, and other DC operators, feel every time we talk about DC and get those famous posts "if you switch to DCC you will only need two wires".
And, as a technical note - I fuse both legs on my DC system.
But what do I know, my trains don't have little brains (and they don't talk back either).
I gotta say, if I was in that club and no one really has much of a clue what the existing wiring was for, I would have pushed for simply running all new bus lines for the DCC system and not trying to patch into the undocumented old DC stuff myself. Trying to reconcile a system built up over years by people who are no longer members (and in an older club may not even be alive anymore) with a modern control system is just asking for trouble.
Our club modular layout recently converted to DCC. The existing DC wiring was mostly just isolating sidings to park trains on, the rest was a simple 2 cab system, nothing sophisticated. Nevertheless, in converting old modules to DCC, all existing wiring was first cut off, then a DCC bus wire was made with PowerPole connectors on each end, and new feeder drops were added on. And it all worked, first time out, mainly because shortcuts were NOT taken.
DigitalGriffin BTW: I love CMR's buildings!
DigitalGriffin
Just for the record - CMR's building are not related to me or my business!
We are a multi-product company - with only a small part being connected with trains!
Sheldon,Obviously, your original comment was sarcasm, and you admit that it was "just a little fun". IOW, we're not to take it seriously. But then you said that your "sarcasm still stands" and detail why that is so. Huh? How are we to decipher that? Sounds like it wasn't "just a little fun" after all, and that it's now a debatable point. Either it's a joke, or it's not. You don't get to poke a stick at a position, retreat behind a wall saying it was just a joke, then continue to poke.
If it's for a laugh, well, consider me amused. and we'll move on to other things.If it's a serious debate point, then let me remind you that my layout is 25' x 50':
And that contolling my layout is just this:
Under my layout is just two wires: one red, one black, and both 14AWG (which you can see in both photos). I have no circuit breakers, no block detection, no signals, no PC connection.
So do you still know for a fact anything more than a 4x8 needs more than the famously advertised "two wires"?
As for sound locos, yes, if one has 40 of them all on the layout at the same time, then you'll need to do something. Either isolate them with toggles or add more power or more circuits. But then that also goes for DC. If one wants 40 engines on a DC layout to all be accessible, then one must also isolate with toggles or do some fancy wiring.
But what do I know, I've only been running DCC for 11 years and DC for 9 before that.
Paul A. Cutler III
Paul, Define "two wires" however you like, but as far as I'm concerned, every one of your drops is "two wires" and the bus is "two more". 10 drops, one bus = 22 wires. And a hundred feet of wire is a hundred feet of wire, no matter how its connected.
"Two wires" is just that - two wires like the feeder from my transformer to my loop of EZ track under my Christmas Tree.
So by my definition two would work fine for a 4x8, as it gets bigger some more wires are needed.
If your power requirements are within the range of one unit, than fine, with enough drops you might power miles of track.
Fact remains most guys with 25x50 have or have plans for more than 4-5 amps of locos - then the fun begins - and you know it. It may not be what you need or want, but most 25x50 layouts are going to need powers districts and ciricuit breakers.
The other point follows, which was also made by many others in this thread - BECAUSE it is more than two wires, good wiring practice and documentation is necessary for a good result and effective trouble shooting of problems. If it was really two wires how could there be any problems?
I had already been doing this 20 years back when you started.
ATLANTIC CENTRAL And then, even with DCC, a whole new infrastructure for signaling. This was a test, Randy passed. He obviously just blew off my comment as the little fun that it was. Those responding to me either didn't get it, or now know how I, and other DC operators, feel every time we talk about DC and get those famous posts "if you switch to DCC you will only need two wires". Sheldon
I'm sorry, I think I missed something. I replied that my layout does have just two wires, and now I failed a test?
Out of curiosity, how exactly does a hidden test from an unknown individual on an online forum help in problem resolution?
Scarpia ATLANTIC CENTRAL: And then, even with DCC, a whole new infrastructure for signaling. This was a test, Randy passed. He obviously just blew off my comment as the little fun that it was. Those responding to me either didn't get it, or now know how I, and other DC operators, feel every time we talk about DC and get those famous posts "if you switch to DCC you will only need two wires". Sheldon I'm sorry, I think I missed something. I replied that my layout does have just two wires, and now I failed a test? Out of curiosity, how exactly does a hidden test from an unknown individual on an online forum help in problem resolution?
ATLANTIC CENTRAL: And then, even with DCC, a whole new infrastructure for signaling. This was a test, Randy passed. He obviously just blew off my comment as the little fun that it was. Those responding to me either didn't get it, or now know how I, and other DC operators, feel every time we talk about DC and get those famous posts "if you switch to DCC you will only need two wires". Sheldon
There was no problem to "resolve". The OP was just ranting. Myself and others suggested that good wiring practices would have avoided his frustration in the first place. And he got his answer about which circuit breakers break both wires.
And I offered my technical opinion in that with my DC wiring I fuse both legs.
Point still remains - since many times it IS more than TWO wires, good wiring practices are needed to avoid problems - rather than blaming products for problems caused by poor installation practices.
As per Bob C and myself, "never enough time to do it right, always enough time to do it again, and again".
If your two wires are neat and orderly, you passed the test.
But what do I know, my trains don't have little brains, just motors and lights.
I think the "DCC is only two wires" is being taken a little too literal when you start arguing that claim by counting each feeder wire as a separate wire. Electrically speaking (I'm an electrical engineer myself) the bus wire and feeders are one, not a bus + Xamount of feeders for a total of Y wires. I don't consider wiring to be "additional" until the circuit is broken or interrupted by a fuse or breaker, because this electrically isolates one section of the wiring from another, regardless if its the same leg or not. Even at that point, I'd still consider it "two wires" if all you're doing is breaking the bus wires into isolated districts. So a bus with 1 feeder, or a bus with 50 feeders, or a bus with 50 feeders and 3 zones is still one wire.
Anyhow of course with boosters and planned power zones there will always be more than just "two wires", the benefit is you don't need the monster amount of cables required to setup more than one cab per power district that is required with rotary knob cab selections with DC ... quit being so literal.
Wow, Sheldon, I'm surprised you're not counting the individual strands of wire inside the jacket of each wire. After all, each one is a different wire, is it not? They just happed to be twisted together,A wire is a conductor that is a path for the current to travel. I have just two paths for current on my layout. Since path = conductor = wire, then that means I have two wires for my layout. Do I have multiple taps on that wire? Yes, I do. Does that somehow multiply the number of wires under the layout? No, just like multi-strand wire, it does not. Especially compared with a typical multi-block DC analog where one has many, many isolated wires under the layout; far more than a basic DCC layout. Care to start counting up exactly how many wires you have under your layout?Oh, and I have a 6-cond. LocoNet cable running under my layout. Does that count as 6 wires, or one?
Sorry, but the idea that large layouts "need" more power & breakers is nonsense. I think I've proven that. Who does need more power are those who want a lot of sound or those that want to run a lot of non-sound engines at the same time, which is not the same thing at all. You could have a bedroom-sized layout with a large engine facility or a full-basement layout with just a branchline going through it. Size doesn't matter here, it's number of engines.
BTW, 4 or 5 amps of engines is still in the realm of one booster (DCC boosters can be purchased in versions up to 8 amps). That's still only one pair of wires (using my definition, not yours).
And I don't have any wiring problems at all on my layout. It's just so simple...red wire, black wire. Black to black, red to red. Don't cross them, and you're fine. I have never had to troubleshoot my wiring other than a bad solder joint or a loose tap connector. Documentation? Ha! Look under the layout...there's two wires. What's to document?You were wiring up DCC layouts for 20 years before I started? That's a pretty good trick considering it's only been around that long. (and yes, that's a joke)
But what do I know, my layout doesn't have 50 pounds of copper hanging off it.
Even taken literally - well there are a lot more factors than just size. I built a temporary 4x8 simple oval with EZ-Track to test run locos on DC and DCC. Even with 4 sets of feeders it was horrible, with obvious slowdowns. Then I built my previous 8x12 layout with Atlas flex track and turnouts. I provided for plenty of feeders, but as soon as the caulk was dry on the last piece of track to complete the loop, I hooked exactly two wires to my Zephyr and happily ran trains around the whole thing with no slowdowns, stalling, or hesistation. Not even a blinking headlight. Exactly 2 wires, one to each rail - all those other feeders were just hanging in space at the time.
Literally 2 wires doesn't work much better on DC than it does on DCC once the layout starts getting bigger. With DC you might compensate a bit buy turning up the throttle as the train slows down, so while it may APPEAR to be workign fine without extra feeders and a power bus, in reality there's a volt or two drop in the rails. DCC you can;t really compensate the same way - the peak voltage never changes other than through losses so you can;t just crank the speed up faster, if the former 15V waveform is now 13V. I suspect over long runs witth insufficient feeders, the Aristo system with PWM control would behave in a similar fashion to DCC. The peak is set by the output of the power supply, ifit drops off due to voltage drop in long wire runs, there;s only so much you cna do by opening the throttle and extending the pulse duration.
rrinker Even taken literally - well there are a lot more factors than just size. I built a temporary 4x8 simple oval with EZ-Track to test run locos on DC and DCC. Even with 4 sets of feeders it was horrible, with obvious slowdowns. Then I built my previous 8x12 layout with Atlas flex track and turnouts. I provided for plenty of feeders, but as soon as the caulk was dry on the last piece of track to complete the loop, I hooked exactly two wires to my Zephyr and happily ran trains around the whole thing with no slowdowns, stalling, or hesistation. Not even a blinking headlight. Exactly 2 wires, one to each rail - all those other feeders were just hanging in space at the time. Literally 2 wires doesn't work much better on DC than it does on DCC once the layout starts getting bigger. With DC you might compensate a bit buy turning up the throttle as the train slows down, so while it may APPEAR to be workign fine without extra feeders and a power bus, in reality there's a volt or two drop in the rails. DCC you can;t really compensate the same way - the peak voltage never changes other than through losses so you can;t just crank the speed up faster, if the former 15V waveform is now 13V. I suspect over long runs witth insufficient feeders, the Aristo system with PWM control would behave in a similar fashion to DCC. The peak is set by the output of the power supply, ifit drops off due to voltage drop in long wire runs, there;s only so much you cna do by opening the throttle and extending the pulse duration. --Randy
Only because you brought it up, I use only one drop per isolated track section (commonly called a block, but that is really a signaling term). Thos drops go directly to the cab selector relay pack for that section, usually only 4-5 feet away. Those cab selector relay packs are fed by the Throttle bus for each throttle, usually somewhere betwen 4-8 throttles. Each throttle bus is #12 wire and is dasy chained in th shortest possible path from the Aristo Receivers to all the cab selector relay packs, which are usually in groups on prewired panels.
Like this:
So power wiring distances are minimized and use large gauge wire until it gets right to the track.
But especially on the mainline, only one feeder is used because those wires must go through a detector (current sensing) and are also tied into a high freguency generator which must be located between the cab selection relay pack and the track.
All rail joints within a track section are soldered. Many track sections are as long as 20-30 feet of track, no voltage drop has ever been noticed.
Except for powering turnout frogs and X sections, all other wiring is 24vdc control level wiring done with CAT5 cable.
Each panel is documented and built off the layout then requiring only a minimum number of connections for final installation.
I know what I do is complex, but good wiring methods and good documentation make it work well.
The system shown in the photo, which I installed on a friends layout, has worked flawlessly for over a year now.
All neatly done and color coded and labeled - until you get to that speaker wire on the right
Reminds me of the club I used to belong to. We just had a 'plain' manual cab system, 6 position rotary switch for each block controllign 5 relays to switch the cab bus power to the block, 6th position was an off. There were I think about 2 dozen identical 5-relay panels spread about the layout, the main yard ws more or less divided in half, and had a dedicated throttle - it was a working hump with air jet retarders. The arrival yard could be switched to any of the 5 road cabs or the yard cab, same with the departure yard.
Track was 100% done and scenery about 50% when we Sawzalled it apart and hauled it away - landlord tried to pull a fast one and triple the rent come renewal time figuring no way would we move after all that work - think again.
Randy, actually most of those are labeled as well, it just does not show in the photo. A few of those are "jumpers" that don't leave the area of that panel, and may not have tags on the wires, but since they begin and end right there, and the terminals are all labeled, no problem. But all the wires leaving the panel areas are tagged and documented on the drawings. And there is a complete layout specific set of schematics that show not only the wiring, but track arrangement, gaps, feeders, etc.
Rent- that's one of the main problems with clubs. I belonged to a club once, when I was young. Learned a lot from some truely great modelers, but I'll never belong to another formal club with dues and a club layout. In my old age of 53 years I no longer care for doing anything by committee.
Thankfully they will never have a rent problem again - they are now located in a building they own outright. Very impressive layotu too, with the track build right from actual track diagrams.
The whole layotu by committee thing doesn;t appeal much to me either. And there are just oo many compromises in design - like building it low enough so the kids can see which means it's too lw for eay operation by adults - stuff liek that. I do help out with the RCT*HS modular layout - if you come out to the Timonium show in February we'll be there. But it's a very informal operation. For the October Timonium show I took along basically a Reading Crossline train - a T-1 and a bunch of WM and B&O cars and a caboose. Not sure what I'll take next time, but everyne gets a chance to rn pretty much whatever they want - as long as there's stuff moving to attract the attentioon of visitors. We don;t do the 'moat' thing to keep people an arm's length away, they can come right up to the layout and look.
Paul3, Thank you for the information and insight.
Ken G Price My N-Scale Layout
Digitrax Super Empire Builder Radio System. South Valley Texas Railroad. SVTRR
N-Scale out west. 1996-1998 or so! UP, SP, Missouri Pacific, C&NW.