I believe I already know the answer but just bare with me and please tell me weather I am correct or incorrect. I am in the process of converting a large engine servicing are from my old layout which was DC to DCC. I have every rail drop disconnect and will be hooking them up to one a Miniatronics PDB-1 board 12 positive & negative terminals each. If by chance I cross one of the rail drops and hook the negative wire to the positive side of the buss it shouldn't effect anything correct being as is AC current correct? The decoder changes polarity to change direction but will this screw up anything with a decoder etc.
I want to do my best to hook everything up correctly but when your working alone it's a gint pain in the butt to keep coming out from under the bench work to switch the ohm meter to anther set of rails.
Thanks for the help.
Allegheny2-6-6-6If by chance I cross one of the rail drops and hook the negative wire to the positive side of the buss it shouldn't effect anything correct being as is AC current correct?
I believe that the answer is incorrect. Even though the bus power is AC, each side of every piece of track must go to the proper "polarity" or phase. If you get a set of wires crossed, as an engine moves across a pair of rail gaps from one section to the out of phase section you will get a short.
(Note that this assumes that you have the railroad broken up into individual double insulated blocks or sections. If you have no insulators, you'll have a short the minute you turn on the power.)
If starting the track connection wiring from scratch, it would have been best to use two different wire colors. I use red and green. And the red wire always goes to the rear track.
This is for rewiring an existing engine servicing terminal round house t/t, wreck track, coaling tower, track etc. the t/t is no problem I was just concerened what would happen if I switched one of the leads for a round house stall. I guess the best thing is just to wire it up and repalce the power supply or buss with the ohm meter and ring out ever circuit.
If you cross a set of track feeders it will be a dead short unless it is to an isolated track section. And even then, when a train tries to cross the gaps into the isolated section, it will short out if that section has the feeder wires crossed compared to the adjoining section.
For track with no gaps, it's easy, just get a 9V battery and a buzzer from Radio Shack and wire it across the main power bus (with the booster disconnected!). If you connect a set of feeders backwards, the buzzer will sound.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
And unless you can turn your layout upside-down to do the wiring, might I suggest red and WHITE as the wire colors rather then red and BLACK, since in less well-lit areas, red and black look similar. Black and white would work as well - just avoid two darker colors or two lighter colors. Contrast is the name of the game. I used red and white because I found spools of #22 two-conductor wire in red and white at Home Depot which I used as feeders (it was two loosely twisted conductors, so easy to cut a length and then split them apart, they weren;t attached like zip cord. I think it was sold as alarm wire), and they had #12 stranded in spools of many colors, red and white being two o fthose - so it was easy to match up.