Wiring a DCC layout

[rrinker]

 Don't bring in the argument about house wiring. It si NOT the same thing. Chek most AC appliances, they are often rated for 100-125 volts, so with 120V coming in and a loss of 10 volts on the wire they still work just fine.

 #14 wire has a resistance per foot somehwere around .0025 ohms. If the load is 85 feet from the source, that's 170 feet of wire. .476 ohms of resistance. At a full 5 amp load that would be a 2.38 volt drop - VERY noticeable as the trains ran from a closer area to the distant one. At a track voltage of 14V that would be a 17% drop. Even #12 over that distance would be a 1.36 volt drop - probably still too much. Much bigger really isn't all that practical - these are times when you use distributed boosters to the power runs are kept shorter.

 Now to a smaller layout, where you might have a 20 foot run, 40 feet of wire. #14 would drop only .5 volt. #12 would drop .36 volt. #12 is not needed here.

 If you happen to have spools of #12 laying around it never hurts to use bigger wire, but if you are going out to buy it new, #12 is about 50% more than #14. Copper wire is anything but cheap these days. My basis is as much economic as it is scientific - if #14 works without excessive voltage drop, why pay more for #12? Free wins all the time though, so if you have #12 or even #10 that you can get for free, by all means use the free wire instead of buying new.

                                --Randy

 

[Texas Zepher]

c&oj3a604

I'm in the process of building my next layout , I'm going Power it with a DCC unit.  I understand the power bus lines should be 12 awg wire.

The only things in my house that uses 12 awg wire are the 220V 5400 watt hot water tank and the electric dryer.  I think that is a bit over kill for toy trains.  I did one layout with 14 awg and then downsized to 16 and 18 gauge wire.   On the other hand I twist my bus wires which most people do not do.   It really depends on how long the bus runs are going to be.   The musuem where I volunteer uses 14 awg twisted but there each block is about 85-100 feet long.

 But I'm at loss for which wire size I should use to feed the  track off the power buss[sic buss] line.  I have a ample supply of 18 awg thermostat wire, would this size be acceptable to feed power to the tracks?  I intend to purchase a DCC system with 8 amp or more to run multiple trains.

Once again it depends on how many feeders there will be in a give block.   If there is one feeder every three feet or so it means a train will never be more than 18" from power.   Most of the time the current will be fed to the train from multiple points as the track is a conductor.  So any given feeder does not necessarily have to carry all the current for a loco or train.   I think 18 to 22 gauge wire is great for feeder.  I also try to use solid wire for the feeders just because I find it easier to connect to the track.  The thermostat wire will work great.

[mfm37]

I'm an N scaler.

As already posted, Size of the bus would depend on the distance the bus needs to run. I use it on my NTRAK modules because it's an RP and the bus runs can be very long when modules are joined into a layout. Too large on a home layout won't hurt but you could be accused of overkill. If that sort of thing worries you.

I also use 18ga Stat wire for feeders. It works but  20 or even 22 is easier to work with and hides better when soldered to the sides of code 80 N Scale Rail. Don't use larger than 20 ga on code 55 rail.

Martin Myers

 

[rrinker]

 18 is fine, although it might be a bit too large to solder to the rails. I'm in HO and use #20 thermostat/alarm wire as my feeders. Even a size or two smaller (bigger number - like 22 or 24) would be sufficient for N scale feeders if you install them every 3-6 feet and keep them short.

 How big is the overall layout, and how long will that bus run? #12 might be overkill - my HO layout is around the walls of a 9x15 room and I am using #14 for my bus with no noticeable voltage drops, nor should I even with 3-4 locos running int he same section, based on wire length and the resistence per foot tables for #14 wire.

                                   --Randy

 

[c&oj3a604]

I should have mentioned I'm a N Scaler.  Will that wire size still work?

Thank You

[ClinchValleySD40]

Assuming you are HO scale, the 18ga wire will work fine (it is what I used).   No sense buying anything else if you have it on hand.

How long are your buss runs?   12ga is very substantial, 14 might be okay also if the runs are not too long.

Larry

 

[c&oj3a604]

      I'm in the process of building my next layout , I'm going Power it with a DCC unit.  I understand the power bus lines should be 12 awg wire. But I'm at loss for which wire size I should use to feed the  track off the power buss line.  I have a ample supply of 18 awg thermostat wire, would this size be acceptable to feed power to the tracks?  I intend to purchase a DCC system with 8 amp or more to run multiple trains.

    I would appreciate any and all information that can be provided.