Just a side note here: (And this is drawn from my experience with the groups I've interacted with over my entire life, so YMMV)
A short is nothing but a (very) low resistence connection between poles. A near 0 ohm resistance is often referred to as a 'hard short'. Since the wires we use are typically very small (thus higher resistence) and the track we use is typically not the best conductor, it is entirely possibly that a mistake in wiring or tracklaying (or nail, or paperclip, etc) could result in a low resistance connection (1-5 ohms).
When dialing up the throttle on a DC power pack, depending on the power pack, you usually get a gradient of voltage ranging from 0 at OFF and 12,13 or 14V at FULL.
So a low throttle setting, say 3 volts, and a 'short' with an equivilent resistence of 3 ohms would draw 1 amp. Depending on the power pack, that may or may not be detected as a short.
The problems really start when the short's resistence drops below 1 ohm.
3v/1ohm = 3Amps
3v/0.5ohms = 6Amps
3V/0.25ohms = 12Amps
etc.
It's those low resistance values that cause the detectable shorts, but the low (but not super low) 'shorts' that cause confusing overload conditions.
Just some theory that helps me from time to time when finding electrical faults.
Cheers!
Dave Loman
My site: The Rusty Spike
"It's a penny for your thoughts, but you have to put your 2 cents in.... hey, someone's making a penny!"
One more thing to think about,which is often overlooked,,,did you add a siding,with a end of track bumper,that was all metal??
Cheers,
Frank
Do You use the Power Pack for any other function,or for just power to track??
Good to know. I never did get a short indication on my MRC or Bachmann power packs, but they were both very basic types, and it was quite a few years ago. With my more recent DCC experience, as soon as you turn on the power you get the dreaded beeps if there is the slightest conflict.
So, I would agree that there's a problem with the wiring on the layout, and it doesn't necessarily have to be on the addition. It could be a forgotten track nail, a piece of solder wire,...
Crandell
selector doubt it, and I would expect a decent DC power pack to indicate a short with as little as 0.1 amp @ 3-4 volts applied.
The pack does not know the difference between 0.1 amps of short or 0.1 amps of locomotive. To the breaker, it is still a 0.1 drain.
selectorTo have to dial up nearly half the power pack's potential before a short is indicated seems to me that the power pack is faulty
Not at all, that is perfectly normal for that MRC pack to require the throttle to get near the 1/2 way point before the breaker opens. Both my 2400 and 2500 respond this way,.
Jim
If there is a short, what is the spec for that power pack to detect a conflct? Would it need half an amp? I doubt it, and I would expect a decent DC power pack to indicate a short with as little as 0.1 amp @ 3-4 volts applied.
Not that I have any experience with DC to speak of....but it seems to me that a short is a short is a short. Apply voltage and something should show you that you have a defect. To have to dial up nearly half the power pack's potential before a short is indicated seems to me that the power pack is faulty or the wiring is 'pinched' and needs a less narrow connection where more voltage and amperage can go through and beyond it.
Those 2400s are pretty good packs. Disconnect the pack from the layout and see if the over load light still comes on.
More likely you crossed the feeders to the new section than the pack failing.
Sounds like a wiring issue, especially with the changes you indicate. When troubleshooting, the first place to check is the last change/addition/modification you did.
The overload light light is probably indicating a short - wires crossed when you added the small end and relocated the power pack. Have you triple checked your wiring hook-ups? Disconnected the wires and/or track for the new section? Reversed the wires for the power pack and see if the problem still persists? Could be something in your new section causing the short.
If you check, re-check all the wiring and the problem is still there - swap out the power pack with another and see if the overload light comes on.
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I have a 6'X10' Ho scale layout (DC) and use a Railmaster 2400 power unit and DC Master for sound. All has worked fine for years until I added a small end to the table and had to relocate the powerpack. Now the overload light comes on at half power and no power to track. Wiring or power pack issue?