Circuit breaker won't trip in one area?

@Jerry A posted:

Hello everyone, I have an issue where my circuit breaker won't trip in one area of my layout. My layout is around 38 by 14 or so and one small area will not trip my circuit breaker. I have the new higher sensitive circuit breakers as suggested by you guys and they work fine except for that one area. I am getting voltage to the area and when I hook up the circuit breaker directly to that area it will trip. Obviously it is a wiring issue but how do I find it? The area in question again is just a small area of about 10 ft of track. Please advise if you would. Thank you very much as usual, Jerry

By chance is this an area where your conventionally run engines slow?  IOW, I'm wondering if the area has track connection issues between the short and the nearest power connection(s), to the point that there's enough inherent resistance between the short and the power supply that the dead short is not drawing enough current to cause the circuit breaker to trip. (BTW, command control systems might conceal the possible problem, by adjusting the speed when the voltage drops in that section).

Also, what is the amp rating on the circuit breaker? If it is, say, 10 amps, it might be a bit too high, especially if you have some connection issues as above. Just spitballin' here . . .

A little vague on exactly what you have in that 10 ft of track.  Is it modern or tubular?  Do you have signals or devices running on track power?  Basic electrical troubleshooting skills would come in handy, using an ohm meter with track power completely off to locate the spot where you seem to describe a resistive short.  If you don't have a meter, inexpensive ones can be found on Amazon or at Harbor Freight.  Use the meter to isolate the problem to a section of track, and with the meter hooked to the circuit, observe it as you move things around, or remove things track related until you get an open indication.

Isolate the area and add its own power drop wired right from the breaker.

@Steve Tyler posted:

By chance is this an area where your conventionally run engines slow?  IOW, I'm wondering if the area has track connection issues between the short and the nearest power connection(s), to the point that there's enough inherent resistance between the short and the power supply that the dead short is not drawing enough current to cause the circuit breaker to trip.

What he said.  This seems to be the obvious choice.  If so, shorting the track there and looking for the hot spot for the poor connection should yield results.

Thanks guys, I just started the wire from the circuit breaker to that track section and it drips fine. I am using very sensitive 10 amp circuit breaker and it trips immediately. I haven't tried them yet with running a train but I hope it doesn't trip too fast. Jerry