test wiring on new layout?

RYoude Jul 18, 2015

  1. RYoude

    RYoude New Member

    I have completed the wiring for DCC on my new HO layout. I have 12 gauge bus and 18 gauge feeders soldered to the tracks. Now I wonder if I can test that there are no shorts before I go onto the next step which will be to ballast. Any suggestions? I am electrically impaired so please be specific. I live far from the nearest train shop so I can't pop in to discuss.
  2. Colonel

    Colonel Staff Member TrainBoard Supporter

    most definitely I would not attempt any ballasting until you have operated the layout and removed any bugs in track work or wiring, you could place a ohm meter across the bus and you should read infinity ohms but i would recommend connecting the layout and running a locomotive over the whole layout
    Last edited: Jul 19, 2015
  3. jdetray

    jdetray TrainBoard Member

    No! If you place the probes of an ohm meter on the two wires of the bus and read ZERO ohms, that indicates a short. If you read infinite ohms, then you do not have a short.

    Again, ZERO ohms indicates a short!

    Other than that, Paul's advice is solid. You should thoroughly test your trackwork and wiring before you do any ballasting. Once trains are running reliably without derailments or electrical problems, then proceed with scenery and ballasting.

    - Jeff
  4. Colonel

    Colonel Staff Member TrainBoard Supporter

    lol im so sorry I'm a fully licensed electrician and signal Engineer lol how could i get that wrong, of course a zero reading would mean a short circuit

    I edited my original post, thanks Jeff
  5. jdetray

    jdetray TrainBoard Member

    I was pretty sure it was just a slip of the typing fingers!
    Colonel likes this.
  6. PaulBeinert

    PaulBeinert TrainBoard Supporter

    Ignoring the fact that I now need to pull out my meter and validate what readings I get ...

    Your turnouts could cause shorts when thrown so test with all combinations of thrown not thrown for any sidings.
    Do you have any reversing loops? They cause additional complexity for testing.
  7. MarkInLA

    MarkInLA Permanently dispatched

    Not sure if this pertains : I believe when people say 'shorts' they mean an 'open' or shortage (lack of) of current. A lack of current as, say, a section of track where a loco stalls for no apparent reason, but later found to have been a bad/loose rail joiner, is an 'open'. A 'short' (short circuit) is current being routed too soon, taking a different path, causing a polarity clash or overload/circuit breaker (if exists) opening to prevent melting or fire. Something like that, anyway. If OP wants to check for voltage loss in a section of track ('continuity check') he can solder a wire to the side (cathode) of a car brake lamp bulb, then touch its tip (anode) to one rail and the wire to another rail, same side of track or opposite rail. If bulb doesn't light, it's an 'open' ( most likely loose rail joiner or power-routing switch (turnout) points not contacting stock rail). But maybe you folks above are on a much more technical discussion than this.. Anyway, just for the halibut, am I right ?... Mark
  8. Gats

    Gats Staff Member TrainBoard Supporter

    The downside of your method, Mark, is if there is a short circuit already. There will be no voltage to operate a lamp. Otherwise, it is a sound method of checking if everything is ok wiring-wise.
  9. RT_Coker

    RT_Coker TrainBoard Supporter

    If you use two 12 volt car bulbs in series you will have a tester that is designed to handle up to 24 volts. The one I have for HO draws about 1 to 1.5 amperes so it finds power problems that a voltmeter will miss.
  10. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

    I would indeed test at this point, using the means already suggested. Best to find out now, then move ahead.
  11. ynono

    ynono TrainBoard Member

    Last edited: Jul 25, 2015

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