Large Scale Central

Wire sizing

I’m getting ready to tear into my various Bachmann steam engines to install RailPro, Phoenix P8 sound boards and batteries. May also add a Phoenix uncoupler or two. I’ve noticed that the newer electronics seem to use much smaller gauge wires in general. Which sizes should I plan to use for various things. I know on my older engines, I’m going to have to mess with the wheel power so I can switch between track and battery. What gauge should that be? Any input is appreciated.

I have been quite surprised at the thin wires that Bachmann uses inside their locos. Maybe 18-20 gauge - this is inside a Spectrum 4-4-0:

The sound systems seem to use even smaller stuff - not really surprising given there isn’t any power involved.

I generally use 18 gauge for everything except battery and motors where I use 14 gauge if I can. RailPro doesn’t accept wires bigger than 16 gauge, so I trim off some of the strands before tinning the ends and they fit with minimal capacity loss.

If you can get silicone insulated wire (sold for test leads, etc.) you will find it is much more flexible and easier to cram into small spaces when closing up the loco.