I was wiring up the replacement motor to my 4-8-4 last night when a question popped into my head as usual. I am wondering what is the smallest gauge wire I can use to rewire the new NWSL motor on my RF&P 4-8-4? I have to run one red wire to the frame of course and a black wire to the insulated screw for the tender pick up. The existing wires were both yellow. I kind of would like to use the same size wire though if possible. Any suggestions?
The size of the wire you need for a specific installation is a function of the wire diameter, the length of the wire, and the current that the installation will draw. In the case of our model motors, particularly the high-efficiency modern can motors, you can use wires as small as 30-gauge for the 2-3" runs you will need. I would recommend, however, a minimum of 28-gauge. NWSL has a good selection of insulated stranded wire. There are those who will tell you that you need something like #18 or 20-gauge wire in this situation, but that’s serious overkill, IMHO.
As far as the color,the “standard” colors would be red for the engine frame, and black for the wire to the tender connection.
Have fun!
You want stranded wire, it’s more flexible and less likely to break. The smallest gauge you can find will work well. It’s only going to run a few inches and the resistance of only a few inches of any gauge of wire is so close to zero as makes no matter. Using the same gauge for both runs appeals to our sense of neatness, but it doesn’t matter. Two short runs of different gauges will work fine. Try to find some small terminal lugs and solder them to the ends of the wires, rather than just wrapping the wire under a screw head.
Number 30 stranded. DCC suppliers sell this in the NMRA recommended colors. Some suppliers even sell the tiny shrink in the standard colors.
You probably missed the DCC/electrical forum.
Rich