wire gauges

[Vizzin72]

I have a 4 x 8 DCC layout composed of EZ track.  I am getting ready to get rid of the terminal re-railers and solder feeders from each piece (or maybe every 3rd or fourth piece) of track. 

my question is as follows:

can i use 22 gauge for the feeders and 16 gauge for the bus? feeders will only be 9 inches long max each and bus wire will be approximately 30 feet long along the track in total.

the 12 gauge from the NMRA standard for the bus , or it might have even been 10, seems over kill IMO


thanks

[brokenrail]

The bigger the better.Too small of feeders under heavy load will causes resistance issues.Just like plumbing if you use a 1/2 inch pipe for flow when a 3/4 or 1 inch is required to supply a good source you will have higher pressure ,but lower volume. This restriction will cause a drop in volume on demand of max volume.In electrical terms brown out,or burnt melted wire when they are too small.Just seems the simplest way to describe how it works being you cannot see the electricity until it jumps out and bites you.
Johnny

[Len]

On a 4x8 I use 12ga solid wire for the bus and 20ga stranded wire for feeders. 22ga might work okay, but I find it gets warm under a heavy load. YMMV.

Len

[Vizzin72]

Thanks , well I definitely don't want any problems so I will use 12 and 20.  I just find it hard to believe that an amp or two could cause wire to heat up but I will take the advice that is why I asked ... The dollar amount between those recommended and what I wanted to use is very small. 

[jward]

I have successfully used 18 guage dual conductor wire on layouts far larger than 4x8, even with dcc the
re wasn't a problem. on a 4x8, you shouldn't have any feeder over about 6 feet long if your command station is properly located.

[Vizzin72]

Well ... I don't really have a good quality command station ... I have dynamis ... So I didn't want to gang the feeders together and then connect them to the unit because it has a small electrical connection in the back so I decided to go with buss wires.  Therefore each feed from the track to bus will only be about 9 inches.  The buss wire will be about 50 feet total to cover the perimeter of the layout and then I'm gonna have the station further away so it is out of the way and so that the receiver is placed in better sight

[brokenrail]

Dynamis has good quality in power to where a booster is not needed unless your going over a  scale mile and a half 2 track with sidings. I can run 3-4 large trains with sound. Only problem I have had is communication with the base .A few mirrors in the layout room fixed that.Bounces the signal.
Johnny

[Vizzin72]

I haven't had any problems with reception but I do get major interference with my tv and or my ceiling light ... The light had to be off or it will NOT work

[RAM]

So you have a night time railroad.

[James in FL]

I have a 4 x 8 DCC layout composed of EZ track.  I am getting ready to get rid of the terminal re-railers and solder feeders from each piece (or maybe every 3rd or fourth piece) of track. 

can i use 22 gauge for the feeders and 16 gauge for the bus? feeders will only be 9 inches long max each and bus wire will be approximately 30 feet long along the track in total.

The buss wire will be about 50 feet total to cover the perimeter of the layout

How many lokies you running at a time? How many with sound? More than 2?
There is absolutely no reason to have a 50' buss for a 4x8 layout. You are adding unnecessary cost, without adding benefit. And you're fighting yourself dealing with wire length resistance. ??
Not sure I understand the logic in that.
A six/seven foot strip right down the middle would suffice (long end to long end and centered). You could spider your feeders from this or tidy it up with a terminal block(s).
In this case, 12 buss and 20 feeders is way overkill, fine enough, running one or two sound lokies.
I too, like plenty of reserve when wiring. And yes, error toward bigger size. That is always good advice.
Just I have to do a CBA to justify.

Well ... I don't really have a good quality command station ... I have dynamis ... So I didn't want to gang the feeders together and then connect them to the unit

[Vizzin72]

I want to put my command station away from the layout on the other side of the room ... I have four or five engines on there two with sound but only one running at a time usually

[jward]

remember that with dcc it is not how many locomotives you are running at any given time, but how many that are on the layout that determine what your current draw is. decoders draw power whether or not they are running or sitting still. this is why I recommend having tracks where you can turn off power to those locomotives not in use.

in your situation, having the command station away from the layout complicates things a little bit. normally, when I wire a layout I use one wire size, 18 guage, for everything. but in your case you'd probably want the connection from the command station to the layout to be much heavier in order to minimize current loss due to wire resistance. once at the layout itself I personally would switch to 18.

why 18 guage you ask? 18 is small enough to solder to the side of code 83 or code 100 rail, yet large enough that current loss due to wire resistance will not be a problem on a smaller layout. if you plan your wiring you can run your heavy guage bus from a terminal block under the center of the layout, and run all of your feeders from this node. you can keep all feeders under about 6 feet in length on a 4x8 layout if you do this.

[Vizzin72]

j ward ... got you.  I have 4 engines right now and with the lights according to info I read they probably only draw about a quarter amp each.  my command station I believe can provide 3 amps.  I tried looking for a specification on 18 gauge and everything i've found says it can handle up to 6 amps.  to be conservative though (and to ensure the wires don't heat up) I bought 18 gauge and 12 gauge.  i'm running the buss with the 12 gauge and each feeder is 8 inches from rail to buss.  I personally think it is major over kill but the reason why I posted is I have no experience so i'm basically going with all of your recommendations (for the most part).  The NMRA i think recommended 10 gauge for buss wire and it was only a couple dollars more but my soldering iron cant easily solder that thick of wire so that is why I wanted to use 12.  As it is i have to clip off a couple of strands just to get the wire to be able to fit in to the connections on the back of the command station.  thanks for your input though and your right soldering 18 to the rails is pretty straight forward.  I was hoping to be able to use 22 gauge because that is REAL easy to solder to the rails.

[brokenrail]

Wire resistance? Should not have any! Connections yes ,if not soldered correctly or not at all. 0.2 ohms can be considered normal per connection. Resistance goes up with temp.So if your locos mechanism is not maintained it will pull more amps to operate and heat up.If not vented properly along with the high switching rate of say a Tsumani sound decoder you will pull more and take the chance of finding that bad connection somewhere if not solder correctly or not at all in the loco ,wiring connections or rail connectors.
I also had some issues with communication with Dynamis this was due to cracked solder joints in the circuit boards in the hand held and the receiver possibly due to the lack of lead in the solder they use now and or a little rough handling. Baked the boards in the oven stripped down completely of everything that would come off at the lowest oven setting for about 5 minutes on a cookie sheet with foil on it untill the smell of electronics that was heating up(If anybody has smelled fried smell of electronics) electronics .That is when they come out of the oven. This was a last ditch effort to fix it and it has worked flawlessly since. Found a article about somebody dong this with a pc motherboard that had success.
Johnny

[Vizzin72]

Y ah ... i mean my solder joints are real good I'm testing resistance from one part of rail to another part and I'm getting 1.8 ohms consistently.  If I test from rail to feeder wire I'm getting 1.8 ohms so I mean there is virtually no resistance measurable being added by the wire.