I just wired up a control panel for phase 1 of my new layout. Everything is working fine but as expected I am now thinking of better ways of doing it. I already posted in the layout design forum on powering and wiring non-DCC turnout controls and indicators which got a lively discussion going. Now a question for the DCC side…
All of the references that I’ve found on the web say to break both power legs to separate track sections (using dpdt switches or other means) - programming tracks, different districts, or just to be able to power down a siding to turn off lights in passenger cars. I remember doing this on my old non-DCC layout which was powered using two independent throttles to run two trains. But thinking about it, why this is necessary for DCC which uses a single power source? If one leg is broken then no power, and no DCC signal, will flow through the track to anything that is parked on it. So why the need to break both legs?
Its called common rail wiring. One rail is powered all the time and the broken section is controlled by switches. The only reason to break both rails is in a reversing section or turn table and wye configuration and separate power districts. Sidings and yard tracks can be separated using a single insulated rail. Power districts must be isolated on both legs because of the current tripping circuit protection. If one rail is common then there will be no distinct power district to protect and possibly the whole layout will trip instead of just the one district.
Pete
Power districts can have two different power sources. Gap both rails.
A programming track on the layout has two different power sources. Gap both rails.
A reversing track effectively has two different power sources. Gap both rails.
A track that is just going to be used to turn power off for lights etc can have one rail gap.
For all other situations, check the manuals that come with the equipment you are using or adding to the layout. Things like block detection boards, circuit breakers, etc.