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As I'm new to the DCC world, and will be installing a decoder in my 1st locomotive soon, I wanted to start off right by using good practice wiring schemes from the beginning.  My research has lead me to the following information for wire color, there are ten colors used in DCC, and they are as follows with their general use:

  1. red -power in
  2. black -power out
  3. orange -motor +
  4. gray -motor -
  5. blue -acc common
  6. white -front light/function
  7. yellow -rear light/function
  8. green -other light/function
  9. purple -other light/function
  10. brown -speaker(s)

Is this correct?  And now for what colors to use for things like smoke units, electrocouplers, cab lights, marker lights, ditch lights, and so on.  My thoughts were maybe to do the following:

  • white -front marker lights & headlights & cab light
  • yellow -rear marker lights & backup light
  • green -couplers
  • purple -smoke unit


  • white -headlights & front coupler
  • yellow -backup light & rear coupler
  • green -cab light & marker lights
  • purple -smoke unit

Or get fancy and find some striped wire for things like couplers (green wire with a white stripe for front and yellow strip for rear) and marker lights (white wire with a green stripe for front and yellow wire with a green stripe for rear).  What do other do?

Note, this doesn't mean wiring them to the same output on the decoder, just using the same wire color.  My brother asked that when I showed this to him, "Wouldn't that mean your coupler would fire when you turn the headlight on?"

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I would recommend not using the light function colors (white and yellow) for other stuff.   You have enough other outputs I think to isolate those.   

While most if not all DCC decoders can be programmed to use any funciton output for lights, it is probably easier to stick to white and yellow.    then use the respective other function outputs for the other things you want which are also default programmed to function keys on your decoder.    

Power in and power out to both motor and rail are confusing concepts to me.    My rule of thumb is the red wire comes to the decoder from the engineer side of the loco and the black from the fireman side.   then the orange wire from the decoder goes to the engineer side of the motor and grey wire to the other.    this has always resulted in the default forward direction being the correct for the front.    Of course you only need to change the value of CV 29 by one if you wire it backwards to change what is front and back.

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