What is a bus wire?

A bus-wire is a single cable that carries power around a layout with numerous wires splicing off it along the way (known as dropper wires) to supply various components or sections of track with the power.

There are two main reasons why you would want to use a bus-wire on your layout. Firstly, for use as a simple common wire carrying DC power to components such as street lighting, building lighting and anything else that could share a common circuit. Using a bus-wire in this way will not only save you on wiring and switches by not having separate circuits for each component but also, it will help to keep your wiring tidy.

The second reason that you would want to use a bus-wire is to deliver power to your tracks in the most effective way. When you connect your controller to the track in just a single location, you are relying on the metal rails to carry power to the furthest corners of the layout, and on larger layouts, that can lead to something called voltage drop. This is because the rails (although clearly do conduct electricity) are not very good at it, especially when you factor in rail joiners, points and corrosion along the way, so by the time the power has reached the far end of the layout, it has somewhat lost its "Oomph" (technical term!) slowing trains down and increasing the likelihood of a stall. This problem is even worse if you are operating a DCC layout because the AC current is relied upon to convey digital messages from the controller to the decoder in your locomotive and any distortion in the signal can hinder your engine's ability to work properly.

Bus-wires offer a solution to this problem. By running a bus-wire from your controller around the whole layout and installing multiple dropper-wires along the way (connecting the track to the bus-wire) the power has a much more conductive and less interrupted route to take and arrives at the far end of the layout with minimal voltage-drop and in the case of DCC operation, an undistorted command for your locomotive.

There are various ways to install bus-wires to a layout and many factors to take into account, so now that you have discovered what bus-wires are and the advantages that they can bring, it is important to take advice on how to install one that is correct for your needs.