Top Tip: DCC, Wiring & Electrical

So far I’ve talked about general wiring techniques and methods, but this issue I’d like to focus on DCC power bus wiring. The principles and best wiring practices discussed will be of use to DC modellers, too.

Creating your DCC power bus A frequent question on forums is ‘How do I go about it?’. It is just as frequently followed by half a dozen conflicting answers. Basically a ‘power bus’ is a wire that is substantial enough to deliver the full power of your DCC system all around the layout with negligible voltage drop. Because DCC uses a high-frequency wave form that creates induction, voltage drop will be MUCH more significant than with conventional DC or AC power unless you follow some basic rules. We only have room to cover the basic ‘dos and don’ts’ here, but for more information please visit where you’ll find lots of real-world wiring information, detail and diagrams. Look in the ‘Manuals and Advice’ section and search for ‘DCC Advice #9: DCC Power and Layout Wiring (Part 2)’ which will give you lots more information in ALL areas mentioned here. Alternatively, use this link: The Basics: Use substantial wire for the power bus; never less than 1mm, and 2mm and larger for bigger layouts. Use stranded wire. Use two separate wires rather than twin cable, and twist them together about 12 turns per metre to help negate any induction. Follow the main track where it’s widely separated. It’s OK to run the bus under the middle of busy track areas and reach each track with droppers of varying lengths, too. Join the controller to the power bus at, or close to, its mid-point. That way the ‘system to bus end’ will be shortest. It’s not an issue for smaller layouts, but with larger or ‘digitally busy’ layouts you should avoid making the bus a full loop. It is wise to break the power bus into a couple of separate sections for very busy or larger layouts to make it easier to isolate specific areas for troubleshooting. Separate areas can be isolated by a simple switch, or you can use purpose-built individual circuit protection for each area.