Hi all - this is likely a dumb question, but I’m still learning DCC. I have one HCD layout that is wired up and running with a NCE PowerCab. I will be adding a second HCD to form an “L” layout. My question is how to incorporate the new door? Should I rewire the existing door, add the new door and have one continuous bus wire? Or can I wire the new door and somehow have two separate bus wires powered by the same system? Would and NCE booster support that? Thanks for any and all advice!
No dumb questions, only dumb answers, and I hope this isn't one of those ;-). You don't need to rewire your existing door unless there are deficiencies you'd like to correct. Otherwise, it's mostly a question of volts and amps. Amps: If you aren't significantly adding to the circuit load, i.e. power draw, by having more trains running at the same time, i.e. you are adding trackage but not more locomotives, then you aren't increasing the amperage load on the PowerCab and so all good. If you are adding locomotives, then you'll need to keep an eye on not going over the amperage rating of the PowerCab. Volts: voltage drops when you lengthen a wire run, counterbalanced by increasing the size of the wire. If you have wiring heavy enough in your existing HCD that can be added to, you can continue from the existing layout and keep your single bus lead. if you don't, or aren't sure, it's easy to run an additional (relatively) heavy wire from the PowerCab.
There is another school of thought if you may someday expand your layout again, and that is to wire each HCD as it's own power district. You do not need a booster at this time, but you can use the existing booster and a pair of circuit breakers to electrically isolate the two HCD's. That way you have a bit of insurance that a de-rail on one HCD does not shutdown the other HCD. A pair of Digital Specialties PSX circuit breakers is not a lot of extra cost. But you get the Ability to learn more about making DCC work and also making sure a de-rail does not endup melting a locomotive truck.
