Electrical testing - May I share my "rookie" mistake?

Model Railroader Layouts and layout building
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Good Morning,

Hope you enjoy the following, which I can laugh at this morning - but sure wasn’t laughing about it yesterday…

Last evening, I was “fixin to” wire up two sets of industrial sidings on my 3 level,15x11 Ho DC layout. I use two Controlmaster 20s, and have about 28 blocks on the layout. I am not an electrician, but I know DC wiring pretty well…

Anyway, I intended for one of the groups of sidings to be a single block, but felt that it needed two sets of leads to assure there was no voltage drop from one siding to the other. I ran the first lead and tested to assure the direction of a loco on said siding was consistent with other powered tracks, and then left the loco on the siding and shut off the power. So far, so good…

Well, then I spliced in two more leads and threaded them thru the benchwork to the far side of the siding complex. Usually, I wire the black (common) wire to the far rail and red (hot) to the near rail. Instead of “just doing it”, I decided to check for the “right” rail by using a connectivity (spell?) tester. As most of you know, this is simply two long leads with a battery/bulb in the center.

Well, I connected one lead to the black wire and touched the far rail with the other. Well, as expected, the test bulb glowed brightly. And then, just for grins, I touched the inner rail - and guess what, the bulb glowed again (although not as bright). Well, Mr. Edison here figured that I somehow had shorted out the siding complex, and the hunt was on…

I looked for tools on the tracks, and traced the few connected wires, and even assured that the sidings were isolated from the main. Yes, everthing was as it should be, but the “short” was still there. I then recalled that once I stapled some wiring under the layout and the staple cut thru the wires and caused a short, but I have not used staples since that tim

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Howdy, Pardner,

After reading of your misadventure, I have but one thing to say:

Been there, done that. [(-D]

Don’t you wish all of your problems were that hard to solve? [:-^]

Chuck (modeling Central Japan in September, 1964 - analog DC, MZL system)

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Wait until you hook up a siwtch solenoid with the common on one end instead of the center. Every time you throw it it goes the same way. That one takes a couple of hours to figure out after you have changed the solenoid and rewired it the same way because you know you did it right. It has to be defective parts.

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Gosh, I’ve been there, done that too!!!

Seriously, the worst electrical problem I’ve had that eluded me for the longest time was the staple that secured two wires underneath the layout. Initally it did not short, but did so after time due to some other wiring project that pulled those wires allowing the staple to cut into both of them. That was a real job in figuring that out, even to the point of chasing me out of the train room for days at a time. Once I found it, ALL staples were removed and the standard “eye” connectors were put into place. Like they say, an ounce of prevention is worth a pound of cure!

ENJOY,

Mobilman44

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I saw that puchline a coming!

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This is not toy train oriented and not even a “Rookie” mistake… but I’ll share it anyway…

I was helping my son-in-law install a GFCI outlet in their kitchen (old house). Unfortunately, I got there after he had removed the original outlet and could only see 4 wires sticking out of the wall box and no way of knowing which one was which, all were black and coming in separate holes in the old metal box. I got my old, trusty Simpson VOM and put it on AC Volts to look for power on any wire, just in case the wrong fuse had been pulled. Found none, so I felt safe to switch to Ohms to try to see which wire was “ground” from the power box. THREE of the four seemed to be ground. I figured some item was probably plugged into an outlet downstream. Went to the lamp on what I thought was the next outlet in the chain.

The VOM needle is now in the shape of a questionmark (“?”) and all the smoke got let out of the coil in the meter! I had left the meter in Ohms and the outlet was not on the same circuit as the one we were working on and 120 Volt power surged right through that poor ol’ meter… POW!

I bought that meter with the entirety of my very first paycheck… all $18.75 of it in 1963. (I miss my meter!)

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Having worked with electronics hobbyists and rebuilt my old 4x8 a zillion times, wiring the layout is no problem for me. My last layout, two 4x8 set up as an L, was going to be completely wired and running in about two hours. With everything wired exactly as planned, I left fo dinner. Upon returning, it was time to grab my least favorite loco and check everything. NOTHING WORKED! I searched here, there, everywhere! After tracing each lead from the control panel to the rails and back again, I finally found the problem. One of our two cats had decided to hop onto the layout and play with anything it could, knocking a small screwdriver off the edge of the layout and into the back of the panel, shorting out by a fraction of an inch the terminals of one of the power packs. Solution? After reseting the circuit breaker, a small piece of electrical tape over the terminals so no more accidents can happen, and no more leaving the brass handled screwdriver laying around! The yard turnouts failed the following week. Guess waht? Cats found the unprotected wiring hanging from the underside of the layout and pulled the common lead out. Solution? Solder the connection, and staple the single wires tight to the underside of the table. Extra solution, close the door even when I was in the room keeping the cats out at all times. I learned my electrical basics from (ok, it’s not a Kalmbach book) the Atlas wiring book as published back in the late 1960’s. There were no cat related warnings in the book. :frowning:

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My favorite boo-boo - and I’ve done it more than once - is putting a locomotive or car on which I have just installed Kadee couplers on to the layout for testing. Of course, there is absolutely no track power, and any selected power source shows a short circuit. Search for hours, can’t find anything wrong. Desperately remove the Kadee couplers in an effort to find the short, but it’s still there. Reinstall the couplers, take the locomotive/car over to the front spur to check the coupler height against the Kadee coupler height gauge one more time. And then - the blinding obvious hits me - that metal coupler height gauge is happily short circuiting any power I apply to the track.

Because I’ve done it more than once, making sure the coupler height gauge is off the layout is now one of the first steps in my short circuit trouble-shooting.

wishing I would get struck by the blinding obvious much earlier in my efforts…

Fred W

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I got into an argument with another forum member about electrical troubleshooting, something I do for a living. This [D)] could not fathom that the many blocks a DC layout has is an advantage when troubleshooting a short circuit.

The blocks make it real simple to break up a layout into many small pieces instead of looking “somewhere” for a short.

The DCC guys would do well if they included some toggles to breakup their layouts as well.

The toggles would not even have to be run back to a control panel, they could be placed under the layout in strategic areas.

Some may say shorts will never occur unless an engine derails but the rest of us know better. It can and does happen.

Jim

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The cat story got a chuckle out of me as I have had the same problem with our cat. I have never seen an animal that has such a fetish with electrical wiring. I have had to splice every speaker wire on the home theater (twice), the playstation, the kids v-smile game (twice), a waterfall light in the bedroom, my computer mouse cable and even the clothes iron cord which he chewed in two as the wife was ironing!! He never did that again! (picture the movie christmas vacation when the cat chewed the tree light cord) Ya’ll say “get rid of the cat…” my wife says “NO”.

cheers…

John

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That cat will eventually get rid of itself… hopefully it won’t take your house with it.

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Our dog chewed Mom’s sweing machine pedal cable. It was connected to a switched outlet that went on with the light at the stairs. I was on my way to my trains(gee this story goes back a lonnnggggg way)and when I hit the light switch, the power came on and the sewing machine raced at full speed! I was just old enough to know how to fix it.

Oddly, the cats don’t bother with power cords or speaker wires. The light weight wires used under my last layout were just dangling too much. My new layout(s) have to be cat, kid and wife proof.(see other threads)