Recommended Wire Sizes by Scale

To read more about the recommended practices for DCC wiring go here: http://www.wiringfordcc.com/track.htm 

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                                         Main DCC track bus wire size recommendations:                           

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You need to have track feeders from the track down to your main track bus wire every three feet on every piece of track for the most reliable DCC operation. Solder together sectional track if possible. Note: Rail joiners are NOT good electrical connections. They provide track alignment only! 

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http://www.dccwiki.com/Wire_Sizes_and_Spacing

Recommended Wire Gauges by Scale

Note: Recommended Wire Gauges Shown in the Table Are For Copper Wire Only, at 60 Hertz, AC, Sine wave. Keep that in mind when making comparisons. This chart is based on a 5A maximum current on the bus. For a 10A booster, move to the next larger gauge (smaller number). Runs up to 100 feet are possible with 12AWG wire, and 50 feet with 14AWG. This is for one leg, in theory, it is possible to have a 100-foot run (14AWG) with the booster in the middle (50 feet on each side). Don't skimp on wiring, plan for future power needs.

Wire Size Guidelines
Wire sizes are American Wire Gauge (AWG)
	BUS LENGTH FENDERS			FEEDERS
	1-20 FT	21-40FT	40+ FT	Up to 5 FT	Up to 10 FT
SCALE
G (1:20.3 / 1:29)Gauge 1 or I (1:32)O (1:32)S (1:64)	12	10	8	16	14
HO (1:87.1)	14	12 - 14		18-22	18-20
TT (1:120)	14			20
N (1:160)Z (1:220	16	14	12	18-22	18-20
N-Trak	12			18-22	18-20
N-Trak is based on the N-Trak Wiring RP for DCC http://ntrak.org/ntrak_powerpole_rp.htm

Metric Equivalents to American Wire Gauge -

AWG	Diameter (Inches)			Nearest Metric Size in square millimeters is
7	0.1443			10
8	0.1285			--
10	0.1019			6.0
12	0.0808			4.0
14	0.0641			2.5
16	0.0508			1.5
17	0.0453			1.0
18	0.0403			1.0
19	0.0359			0.75
20	0.032			0.5