# How to discover a short in DCC?



## gdancer (Feb 19, 2008)

Don't laugh please! Or, go ahead and laugh, I can take it! I have screwed up my wiring on my 450' layout that has no blocks in it. I know that I will have to segregate sections of the layout to test for shorts. What sort of tool for testing for shorts can I use? In HO, I had a small tool that when I crossed one rail to the other through a bulb the bulb would glow weakly if there was a short, or brightly if there was no short. When I worked on my layout last summer--it's at a summer home in Colorado-- I discovered the short by burning out the power decoder in one of my locomotives. I now know at least to take my locomotives off track before testing for shorts! Duh! But what can I use to test? I normally operate at around 20 volts DCC. Can I use a regular 20 volt AC or DC bulb in the same way I could use a 12 volt DC bulb in HO? Do you know of an easy-to-find tool? Help, please. And go ahead and laugh.....


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## Greg Elmassian (Jan 3, 2008)

ok, so what I do is I have about 8 power districts, all separated with insulated joiners....so first I just unplug each section so I know which district has the short. 

Then to find the short do the same thing with a 24 volt bulb across the rails starting at the feed point, the light will get dimmer once you get past the short. 

Greg


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## toddalin (Jan 4, 2008)

Posted By gdancer on 22 Apr 2013 12:39 PM 
I have screwed up my wiring on my 450' layout that has no blocks in it. I know that I will have to segregate sections of the layout to test for shorts. 



Did it ever work or was this the initial shake-down? If it never worked, did you accidently include a reverse loop? Do you have multiple feeder wires where one set could be reversed?


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## gdancer (Feb 19, 2008)

Thanks, Greg. You've given me the answer. A 24 volt bulb will work fine. I know I'll have to disconnect sections and test for the short that way. I take it that the bulb does not have to be some sort of special bulb, just DC. toddalin: I've operated for about 6 or 7 years and don't have any reverse loops. H/e, I did put in a large expansion but operated on it also for a short (no pun intended!) period of time. Then, while trying to change some wiring on the day before we left my pike for the fall-winter-spring I fried a decoder and quit then until I go back this May. Thanks to both of you. Dick


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## chuck n (Jan 2, 2008)

What engine did you have on the track when the short happened? Some engines have trucks that on the engine or tender that can get turned around causing a short. The pilot trucks on the Bachmann 4-6-0s are particularly prone to this problem, or so I have heard. I had a problem once that I traced to the tender of my Bachmann 2-8-0 one of the tender trucks got turned around. This wasn't Bachmann's fault. I had replaced the trucks on the tender and they could easily get turned around.

Are you sure that it is in the track and not the rolling stock?


Chuck

I will be the first to say, that I don't know anything about DCC. But if the short was in the track, wouldn't the circuit breaker on the power supply pop. For the engine to blow, it seems to me that the short has to be in the engine.


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## toddalin (Jan 4, 2008)

Posted By gdancer on 22 Apr 2013 09:10 PM 
toddalin: I've operated for about 6 or 7 years and don't have any reverse loops. H/e, I did put in a large expansion but operated on it also for a short (no pun intended!) period of time. *Then, while trying to change some wiring on the day before we left* my pike for the fall-winter-spring I fried a decoder and quit then until I go back this May. Thanks to both of you. Dick 

Then this would be the first place to look.


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