12 Gauge is for the track bus. Remember, N-Trak strings multiple modules together, so you can have fairly long bus runs with multiple connectors. In order to maintain 1) reliable performance (i.e. less than 1 volt drop at the far end of a district) and 2) reliable short circuit protection, the heavier wire has been unofficially recommended for some time. The recent RP "officializes" the 12 guage recommendation, and includes a more robust (and more economical) connector. Here's the original proposal: http://home.comcast.net/~dstuard/powerpoles/NtrakPowerpole.htm Doug
House wiring is rated for maximum permissible heating effect. On longer runs you need more copper to keep volt drop reasonable. The lower the system voltage, the bigger the problem. Don't quote me on the numbers (I'm not familiar with US electricity ) but for example maybe you have a circuit supplying 110V into a 20ft run of 18 gauge wire with a 5A load at the end. Say this results in a 5 volt drop along the run. So the load gets 105V. Take the same wire, supply it with 14V and put a 5A load the other end. The load gets 9V.
Oops - I'm not even thinking about voltage drop for hundreds of feet. I'm not a club member or anything and that didn't even cross my mind. I'm still thinking 8-10' runs. 18AWG wire with a 5A load would result in a 6V drop over 100'. That would be significant. 12AWG wire would result in almost 2V - quite a difference. I infact used 18AWG solid wire for my layout bus because my bus amounts to only 10 feet! So I am in good shape.
Newbie here, Just so I don't get too confused (and pardon me for taking the discussion off track even further) aren't occupancy detector blocks and power districts the same thing? I mean, I thought the purpose of the occupancy detector was to signal your computer (through software) that a train was in a certain place moving at a certain speed in a certain direction... So the power districts, at least I always thought, were to allow uniform current over the layout and provide for a way of tracking and with enough sophistication having a signal system that actually worked. Am I off base?
JonP Welcome to Trainboard. Power districts and occupancy blocks are two seperate things. Occupancy you hit on the head. Power districts are two electrically seperated sections of the layout fed by a different Power boosters in a DCC system.
Maybe it's my way of looking at it. From your post I am taking that a power district can be "enhanced" to be an occupancy detector district as well, but one isn't necessarily the other. I am just in my infancy learning about DCC and computer control (not always the same thing) and from what I've learned having the computer be able to spot a loco in a certain power district/occupancy area is one bedrock to computer control. Once again, sorry for dragging this to an area it may not have been intended.
JonP: Welcome to Trainboard. A power district is part of your layout that is powered by an additional command system that is wired to the main command system. The power district supplies voltage to a different part of the layout. A loco can cross from one power district to another without losing power. Block occupancy detection allows one to follow a train as it enters and leaves blocks on a layout. You can have many blocks in a power district or you can have a power district that is not blocked at all. I created a second power district on the JJJ&E which controls my switching yard and turntable with it's holding tracks. There are many locomotives in this district. The double main line of the JJJ&E , a small four track yard and several sidings are controlled by the main command module. The power district's command module is wired to the main command station so in essence one handheld device can control all loco's in both power districts. The handheld device is wired to the main command station and not to the second power district. BTW, you don't need a computer for block occupancy detection. Lenz for example, makes block occupancy detectors that are wired to blocks and the main command station. I have feedback modules that relay the trains position to my main command station so I know which block hold certain trains on the layout. It may sound complicated but it isn't. Hope this helps you out. Stay cool and run steam....
Ok, Thanks, I am learning. I thought differently, but then again I am a neophite here. My long term plan is to create a basement layout that simulates real time passenger and frieght operations (multiple trains running at the same time controlled by predetermined routines on a computer) while I can take out special trains under a control system that will prohibit collisions (signal system.) Of course this is a pretty gargantuan task for a person, especially considering my lack of knowledge. But it all starts with learning. Retirement is looming for me in a year or two and now that I finally get a basement I can work on dream realization. I'm going to start small and experiment for a while. This is a great place to learn from pros. Thanks, John
John, that is exactly what I am doing. I am starting with a small layout to get kind of a sense of completion with this small one to keep up my interested and enjoyment. If I am still interested and having fun, I will then dive into my large layout in my garage. I have 36' X 10' to work with if I ever decide to go big out there.
Oh that's great Sheldon. My space, if I take advantage of it is around 27' X 13'. My wife just about had kittens when we were at our final layout meeting with the construction guy. I showed him a change in a room that essentially houses a sump pump in the corner of our 23X25 Recreation room (a finished room on the other side of the basement from my unfinished train room.) The change in the room configuration was to make it so that there was about 15" of wall between the basement outer wall and the door to the room. The Construction Foreman asks, "Why would you want to do that?" I say, "I'm planning to add a wall mounted extension line to a model railroad in the storage room. You know, to let it travel around the wall? I'd really rather not go through a door." The wife goes, "Are you nuts?" That plan is a few years off if ever. But it'll be a real possibility when I get ready. One thing I'm going to have to work out is how much of a grade a loco can stand because there is one doorway to go over... but that'll be a fun thing I'm sure. I hope you do some posting on your layout and your experiences with computer control and DCC. You are probably way ahead of me since I don't have much but a foundation right now. Thanks, John
