I have a good sized layout, use TMCC for all of it. The yard is a separate block with both TMCC or conventional power. The TMCC power is provided by a Lionel Z and the Yard in conventional mode is powered by a post war ZW. Somewhere I have a short in the non-Yard area of the layout. Except for the Yard, the layout is a single power block, with lots of feeder wires to the tracks every 4 to 6 feet. The feeder wires were added over time as the need was identified, and as I built additions to the original setup. Add hoc additions have been made from the central power distribution board, or added to the existing "network". I made a major change several years ago replacing all my O-42 curved track with O-72 or larger and also replaced the swithches outside the Yard with O-72 K-Line switches. Coppeer prices at the time were in the stratosphere, so I reused wire, with splices where needed, when I made the changes to the feeder wire network track power. In other words, IT IS A MESS under there! The only good news is that the Switch Track power is still A-OK.
I need suggestions on how best to find that Short without just ripping out all that wire and starting over.
Turn up the power just enough to not trip the breaker(s) and use one of these tools to locate the heat source - finding your short.
Rob
If the resistance of your wiring and the short circuit are not high enough to keep from tripping the transformer's circuit breaker, you may have to use an alternative to the Z or ZW that allows you to go to lower voltages than these transformers' minimums, for example, a 1033 with the B terminal as common, instead of the usual A terminal, or a KW using C as common instead of U.
If you have a voltmeter with a low range, you may be able to home in on the short circuit by measuring along the track to find the location with the lowest voltage between the rails. The short circuit may be in the track itself or in the feeders close to that location.
Bob Nelson
If you can't find a hot spot then all you can do is the hard way. Disconnect one wire at a time till you find the short.
"IT's GOOD TO BE THE KING",by Mel Brooks
Charter Member- Tardis Train Crew (TTC) - Detroit3railers- Detroit Historical society Glancy Modular trains- Charter member BTTS
I have a few thoughts none that you will like to hear but! will assume your using O or O-27 track look to see if insulator missing in a section of track.
the other this is a good time to rewire and make it neat and as your rewiring see if a short pops up then fix it.
or you can remove a wire at a time as suggested until the problem shows up!
Thanks for the prompt and thoughtful replys. You folks are like having expert consultants "on call" with multiple lifetimes of experiances to draw on.
I ordered the suggested Black and Decker temp. gun last night, so when it arrives, I'll let you know how it works out.
I didn't mention in my first post that 99% of my track is K-Line Super-K or Super-Snap with plastic ties so I only had a handful of track to check rail insulation .
You don't necessarily need a heat gun to find the short. Turn up the power enough so the circuit breaker does not trip, and just run your hand along the rails. The short will show up as a hot spot you can feel.
Larry
TrainLarry...just run your hand along the rails. The short will show up as a hot spot you can feel. Larry
If you assume the short is along the rails, this would work.
Where do you buy your wire? Copper prices are up but I can buy a spool of 14 stranded for under $10 on sale. Try home depot for deals on wiring by the spool or foot.
I built my layout using 7amp breakers in series with all the power blocks and 3 amp breakers for accessory voltage and lighting. When I have a short the breaker for just that section pops making it easier to trouble shoot.
If everything is spliced back into a blob your going to have problems finding the short unless you can isolate a section of the layout at a time. When you redo the wiring here is what I reccomend:
Good luck. Have fun.
71835 how about coming back to tell us your progress.
I have not provided a progress report because I have not really made any. After the temprature gun arrived, I've only gotten down to the celler for about half an hour to try it out. It was not very productive because I would no sooner get under there on the creeper than the breaker would do it's thing, and I had to creep out from under to reset and lower the voltage. I am still looking for the voltage that will heat up the shorted wires for detection, but not trip the breaker. This is one of those times where it would be nice for a second person to help out, but none are at hand for the time being.
Also, other family matters have taken up a lot of time, so I have not had the chance to get back under the table.
When I have something to report, I'll let you all know. I really need to get this railroad back to play, er, ahhh, I mean work.
I'll repeat my comment from above:
71835,
The wiring to the layout may not be what is going to get hot. The actual point of the short may be on the layout itself, and that is what will get hot.
Make sure the circuit breaker in the ZW is not defective by disconnecting all wires to the transformer and turning up the power. Disconnect one wire at a time from your distribution network and apply power. This way you can isolate where the short is on the layout. Since there is a delay in tripping the breaker, turn the power all the way up to really heat up the shorted area. The shorted spot will stay warm even after the breaker trips, allowing you time to find it. Leave the transformer on, and let the circuit breaker cycle if necessary to keep the shorted spot hot.
First things first: you have removed every blessed engine and car from your system one at a time first, right?
Jon
Sometimes a lighted caboose or passenger car can deveop a short in the roller assembly. Dab on some liquid tap on to the soldered joint to solve this problem. As others have said, you may have an insulator missing from a sectionj of track. This actually did happen top me once.
Maybe he'll come back someday and tell us what he found.
I know it has been a long time, but here is an update on the short in my layout.
As time allowed, I have been tracing wire one at a time from main power distribution site to it's track connection, confirming continuity to the wire's end point on the layout.
To make a long story less long, I found the short under the layout where 2 wires crossed each other at a point where each had been spliced. the tape had dried out, fell off, and the hot and ground wires found each other. I always offset hot and ground splices in a joint so this can't happen, but when you get 2 wires involved, that method fails big time.
Lesson learned.
With family health issues this past year, trains had to take a back seat.
A heartfelt THANK YOU to all how have offered helpfull tips and suggestions.
train folk are good people!
Greg
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