Multiple Boosters - Central vs Remote : LUSENET : Wiring for DCC : One Thread

Currently wiring a club sized walk around railroad for DCC. The mailine is approx 800 feet in length. Reading Alan's recommendations, he suggests centrally locating boosters. This could put a booster almost 80 ft from the section of railroad it powers.... is this a problem ? Railroad is currently wired with #12 bus wire, what is the practical distance for a booster controlling a section of railroad without worrying about voltage drop ?



-- Bob Perrin (, May 28, 2000


Noticable effects of voltage drop is somewhat subjective, and dependant on amperes drawn by locomotive(s) and other track loads like passenger car lighting. But voltage drop can be calculated. For a given acceptable voltage drop with a given ampere load, the maximum feeder length of a 2 wire out-and-back pair is:

Feederft(max) = 1,000*(Vdrop)/(LoadAmps*(2wires)*(ohms/1000ft))

For HO scale a 1 volt drop is barely noticable, and load amps will most likely be less than 3 amps. With this criteria, the above formula tells us: (2 wires) AWG ohms/1000ft max feeder ft 18 6.38 26 14 2.53 66 12 1.59 105 10 0.999 166 Note that unwanted voltage drop will also occur between the low voltage transformer source and the DCC booster. So it does little good to locate just the booster closer to the track section if the transformer feeding it is still back at a central location. To avoid this problem you must also place the transformer out there close to the booster. That means running the 115 Vac out there too. Be sure to follow wiring practices as acceptable to local electrical safety codes. DonV

-- Don Vollrath (, May 30, 2000.

Sorry about that...The message system doesn't like spaced tables.

Wire data (solid copper)= 18awg,6.38; 14awg,2.53; 12awg,1.59; 10awg,0.999 ohms/1,000ft.

Acceptable 2-wire feeder distance, 1 volt drop at 3 amps = 18awg,26 ft; 14awg,66ft; 12awg,105ft; 10awg,166ft.


-- Don Vollrath (, May 30, 2000.

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