While I was starting to lay the track to my yard, I ran into a problem. What gauge of wire do I use? I know from my previous DC layout that electrical power gets lower the farther it travels. If I go about 12ft., what gauge of wire do I use for the bus? What gauge for the feeder wires? Anybody experienced in wiring, or knows what they are doing, sound off.
it depends on the length of the run. a 12' run could use 16awg or 18awg wire for the buss with a 20awg to 24awg feeders to the rail from the buss. my buss run on my n scale layout will be 70' long using 14awg stranded wire with 20awg for the feeders. i used 14awg because i got it for free and had it on hand when i began building my layout.
#16 AWG (the size wire used in lamp cords) is enough for buses on all but the largest layouts. Lots of people use #14 AWG house wire 'cause its readily available and mechanically rugged. Electrically its bigger than necessary, but that doesn't hurt anything. I don't use #12 AWG house wire because it is too stiff to bend easily with long nose pliers. Feeder wires (short feeders that is) can be thinner. #22 or #24 AWG or even smaller works.
You can find a "copper wire table" on the Internet. Such a table will give you the diameter in inches and the resistance in ohms per foot, or ohms per 1000 feet.
As a rule of thumb, the wire is thick enough if the voltage drop is less than one volt. Voltage drop V = IR where I is current (in HO use 1 amp for planning purposes) and R is the resistance of the wire going out AND coming back. Or, for HO, just keep resistance down below one ohm.
train_frk-0079What gauge of wire do I use?
I know from my previous DC layout that electrical power gets lower the farther it travels. If I go about 12ft., what gauge of wire do I use for the bus?
What gauge for the feeder wires?
Model Railroader magazine