For the bus wire on my OO gauge DCC layout I've used 1.5mm "twin-and-earth" wire as recommended in several places. This is easily obtainable from the likes of B&Q and Wickes, who sell it in several pre-cut lengths. You just strip the grey outer covering off - easy pulled apart by hand once you've used a sharp knife to cut the first few inches - and then you have separate blue and brown solid copper wires for your bus, plus an equivalent length of unsheathed copper earth which you don't need for DCC. I've then threaded these wires through the centre of the baseboard crossmembers, about 3-4 inches apart but parallel. About an inch of covering is stripped off at intervals so that droppers can be soldered on. This means any droppers only have to go to the centre of the baseboard so are always short and hence can be connected with thinner wire.
1.5mm is fine for any reasonably-sized layout (mine is 28ft by 8ft): only if you have a really big layout, eg O gauge or a very long run, would you go to the next size such as 2.5mm.
I folllowed the recommendations in Lionel Strang's book "DCC Made Easy" which is easily available on Amazon or Ebay. He uses 22-gauge wire (1.6mm) for his 30x20 layout for the bus, with 22-guage (0.6mm) for the droppers, which is what I use. The droppers can be either solid or multistrand - 0.6mm solid copper wire is easily obtainable in the UK amd is my preferred type.
1.5mm is fine for any reasonably-sized layout (mine is 28ft by 8ft): only if you have a really big layout, eg O gauge or a very long run, would you go to the next size such as 2.5mm.
I folllowed the recommendations in Lionel Strang's book "DCC Made Easy" which is easily available on Amazon or Ebay. He uses 22-gauge wire (1.6mm) for his 30x20 layout for the bus, with 22-guage (0.6mm) for the droppers, which is what I use. The droppers can be either solid or multistrand - 0.6mm solid copper wire is easily obtainable in the UK amd is my preferred type.
