Correct wire length from track to power bus.

[Howardr]

Greetings,

 

I’m building a 16 foot long by x 6.25 foot wide HO layout using Bachmann EZ-Track, why EZ Track?  Because this is the way it all started years ago and I don’t want to lose my investment.  Any further extensions in the future will be normal sectional Atlas track/flex track.

 

In the meantime my question is regard to track power feeder wiring.  What length of 20 gauge wire can/should be used between the track and power bus?

 

The EZ track has a lower profile regarding the rail web and I’m trying to decide what gauge wire to use to solder to the track feeder wires and then attach them to the power bus.  Either 18 or 20 gauge wire?  Seems the 20 gauge wire fits in really nice but I’m wondering if it’s the right gauge to attach to the power bus…can it take the voltage of my NCE Power Cab DCC system which will be upgraded to 5 Amps after all is working.

 

How far can I run either the 18 or 20 gauge from the track to the power bus and width of the setup being 75” do you think I will need 2 power bus runs?

 

Because I now have somewhat poor eye sight at my age and the space on EZ track between the rail ties is really narrow, I’m going to just take a piece of wire about 1/16” long and solder it to the rail web then run the wire down under the layout.  First time I’m doing this.  Soldering skills, well???

 

Any help and suggestions would be appreciated. 

 

Thanks

[MisterBeasley]

My feeders from the bus to the track are about a foot long.  I run the bus along under the track below the layout, so that's long enough to reach easily without awkward stretching.  I use #24 or #26 wire for feeders.

[FlattenedQuarter]

I have 12AWG bus with 18AWG feeders up to 24" mostly because that's what I had on hand 

[peahrens]

I relied on The DCC guide suggestion of 20 - 22 AWG feeders.  They did not specify length but I recall elsewhere ranges up to 18" or more.  I used 22 AWG solid as I liked the way a 90-degree bend at the wire end let it lie nicely in the outside of the rail web.   

I tried a calculator online (there are many) and (for DC) it showed a 0.1v drop per foot for 20AWG at 5A.  Your overall goal is about <0.5v drop and if your main bus is reasonably sized and the feeders of moderate length you should be in great shape.  For 22AWG, 24AWG, 26AWG feeders the calculator says 0.16, 0.26, 0.41 volt drop per foot, respectively. 

Voltage Drop Calculator

You ask about the number of (power) main bus runs.  I suggest you define how many separate power districts you want, as each bus run from those sources must be within an AWG / length criterion.  The DCC guide recommends (for 5A) up to 25', 40', 63' bus runs for 16AWG, 14AWG, 12AWG respectively.  Try running bus routes mainly near the mainline (you can add branches, just pay attention to total distance from the source).  

If only one bus, and you had a big oval, your bus (roughly under the oval) would be less than 45' long.  If your NCE booster were in the middle, you could run out 22' in each direction.  That's just within the 25' length recommended for AWG 16 bus recommended by the DCC guide.  There are all kinds of ways you can run the bus(es).  Typically, you would not run a single fat bus down the middle of the length of the table and have 3' long feeders.  It could be done, with the right AWGs, but would be unusual.

So, you have options.  You can run your bus along the mainline, or split your bus at one end into, say, three parallel strips 25" apart down the length of the table, etc.  If you follow the feeder length criteria, the best bus arrangement should fall out from the track arrangement & number of circuit breaker "districts" you have.