Is 12 GA to big for a main bus wire? I just switched to DCC and purchased Digitrax Extra Chief 8amp system and I wanted to get the wires installed before the system arrived. Thanks for your help.
Depends on how long your bus will be. Minimizing voltage drop under load is the key to sizing a bus. Too large won't hurt. Too small will result in large drops in voltage. If in doubt, err on the large size wire.
Martin Myers
Thank you, the layout is 22x16, ill just stick with the 12GA
I calculated that this will result in a voltage drop of 0.864V at the farthest point (11+8 = 19, say 20 feet) assuming you have the booster situated at the center of the long side of the 22x16 when running at full 8 Amp. If you run normally 16 engines (pulling load not just idling), or if your layout shape results in a longer run than my guess of 20' then you might need 12 gauge.
As an example I have a 21x6' layout with 15' max run and I am happy with an 18 gauge bus at my typical of 2-3 engines running at a time. I pass the quarter test in each corner and haven't noticed any slow spots.
#12 is pretty expensive! Use the money for something else!!
Meant to say that 12 gauge wire will be a drop of 0.6V when all 16 engines are pulling current at the farthest spot. Check this: www.wiringfordcc.com/trakwire.htm
NP01 I calculated that this will result in a voltage drop of 0.864V at the farthest point (11+8 = 19, say 20 feet) assuming you have the booster situated at the center of the long side of the 22x16 when running at full 8 Amp. If you run normally 16 engines (pulling load not just idling), or if your layout shape results in a longer run than my guess of 20' then you might need 12 gauge. As an example I have a 21x6' layout with 15' max run and I am happy with an 18 gauge bus at my typical of 2-3 engines running at a time. I pass the quarter test in each corner and haven't noticed any slow spots. #12 is pretty expensive! Use the money for something else!!
Ive already got a bunch of 12ga, thats why I was hoping to be able to use it and not buy something else, Thanks for the info, im new to this DCC stuff.
If you already have it then use the 12 ga.
Bear "It's all about having fun."
Use your 12 gauge. That layout is large enough for at minimum 14 ga.