I am setting up a 9’ x 12’ shelf layout with a 10’ peninsula using a Digitrax Zephyr system. I have set it up to have five (5) power districts, with two remote Digitrax plug in sites for a UT4 & a UT1 walkaround throttle. This is a standard gauge, HO scale layout. I have a Digitrax PM42 and another DCC specific circuit breaker for extra protection as well. So that each district has its own circuit breaker.
My question is do I need to have DPDTCO (Double Pole Double Throw Center Off) switches to control each district or can I leave these out of the scheme. I do not plan to have more than one(me) or two operators at any one time. The layout is not that big nor is there continuous running available. I do not think I do but I would like to get some feedback about it.
Five power districts for that size layout seems to be overkill. We have a 20 x 40 foot HO scale club layout with only three power districts. The term power district implies a separate booster for each, not DPDT toggle switches. Our layout has toggle switches only because it was originally built for DC operation, but they do come in handy for sidings when someone wants to park a sound-equipped engine and not have it continuing to emit distracting idling sounds.
Yes, the term “Power District” does seem to get used incorrectly at times. I, too, generally think of it as a section of a layout with its own power booster. Some modellers, though, use it as a section which is isolated and may (or may not) have its own circuit breaker, but not necessarily provided with a booster.
In either case, though, there is no need for a toggle switch. If you’re using a straight circuit breaker, then you should have no problems as long as everything has the right polarity when it’s wired together. (If you’ve got the wrong polarity, of course, you’ll have nothing but problems.)
Another example of an isolated section is a reverse loop, or reverse track, where a train enters in one direction and can come back to the same track facing the other way. These do need special isolation, which may involve either a manual DPDT toggle or a DCC auto-reverser.
A section of your layout protected by a circuit breaker (or auto-reverser) will be limited by the power capacity of the breaker, not by the generally larger capacity of your whole DCC system. For example, my Lenz DCC system puts out 5 amps, but the reversing track, controlled by a Tony’s PS-REV, is limited to 2 amps.
I guess it sort of is overkill, but the layout is a pint to point with a yard at each end, a yard sort of in the middle and the peninsula is one LARGE industry ( a Cement plant with a dedicated concrete products facility) and lastly one multi track industrial park. So I have the layout divided into a power district (LESS any separate boosters) for each yard, and the two industrial areas. It has never been a DC layout. It is a new one still under construction. Also I am using Atlas code 83 flex track that has feeders for each and every piece of flex track.
Well, it may be overkill, but it’s good overkill, and at some point you will be happy you did it. You will have a problem where one section shorts out and shuts down, and by having all of these separate breaker-protected regions, it will be much easier to isolate and fix the problem.
Good luck, and keep us posted. I think pictures of the cement plant will be interesting.
Sorry, but I disagree with the idea that you need circuit breakers.
I’ve been running my 25’ x 50’ HO Digitrax Zephyr layout for 6 years now with no circuit breakers at all. We run with 3 operators every other week, and I have 2 freight yards, a passenger terminal and a staging yard.
The only “problem” with one block is that when someone throws a switch under a loco in a yard, it kills power throughout the layout. While this is a little annoying, it does let everyone know that someone screwed up (they can’t hide it when all the locos stop). So it’s kind of a trade off.
I have yet to have a wiring problem that needed to be chased down that a breaker would help with. I’ve had dead spots, but never a short that wasn’t immediately apparent what the problem was (IOW, a derailed car).
Do the wiring right, and you’ll never have problems.
At my club, we use a lot of breakers (36 at last count). But then we have 8 boosters running and 8 BDL168’s for block detection, too. It’s not easy putting a layout into a 6300 sq. ft. room.
That PM42 can break the layout into 4 ‘power districts’. The advantage is that if you derail or run a switch, only the ‘power district’ the derailment happened in is affected. Be aware that the Zephyr only has 2.5 amps of power. You may have to set each of the PM42 districts to something lower like 1.5 amps and ‘faster’ trip current so the PM42 power district trips before the Zephyr does.
An alternative is to wire 1156 automotive lamps is series with each ‘power district’; this will limit the current to 2.2 amps in each ‘power district’. The problem with this solution is that the lamps are ‘slow acting’, and the Zephyr may trip before they heat up and start limiting the current. All of this really is only needed when you have multiple operators running on the layout.
Everyone else seems to know what you are talking about. I must just be slow, because I don’t. What would you use the switches for? What would they “control”? Just on-and-off, if so why wouldn’t a simple DPST work?
Texas Zepher: I was thinking about using DPDTCO switches as that is what I had on hand. I as thinking of using them as simple on off switches. However, I am now thinking WHY bother?? I am only going to operate with a max of three operators and never a dispatcher, all the turnouts are manual and everyone can see and hear everyone (there are no view blocks) so why bother with separate on/off. The only real use that I can now see is to control my on/in layout programming track which is also the track in the engine house. that way I can drive a locomotive in program it and drive it out.
To all the other responders: The more I think about it the less sense it makes and the more difficult the wiring is. So you all have convinced me to get rid of the switches (the electrical ones anyway!!). And just rely on the circuit breakers.
As for the keg, while there is not a real one on the layout, only a microbrewry, there are plenty of cold ones in the frig’ just around the corner. Anytime you are in my neck of the woods stop in!! [#welcome]
I used DPDTCO switches on mine. I have 10 breaker protected power districts in a 12’ x 12’ layout with a staging/storage area underneath. Again, while it too may be overkill, it will be very easy to add additional boosters later, if needed (I already have 3 [^] ). You’ll be happy you broke your layout up into power power districts. The swicthes are your call. The upside is that it allows you to quickly disconnect an area, if needed. The downside is the cost of the switch, the control panel space and the additional wire.