I am still trying to come to grips with the notion of heated rails on a DCC layout.
So, what we are saying is that too few feeders can result in heated rails without tripping the booster?
Can this only happen with shorts or also on a wiring with correct polarities?
What effect does this have on parked locos on those heated rails?
Rich
Alton Junction
It requires a combination of too few feeders and loose rail joiners. I've never noticed this over two layouts now even though both were initially tested before connecting all of my feeders, and no, I don;t solder my rail joints, just on curves. I Do use NEW joiners when I lay each section of track - I have some that have been connected and disconnected many times and they slide on with almost no resistence. I use those when trial fitting things and cutting flex to length. But when I go to put the next piece of track in place for good, I grab a fresh pair of joiners from the package. - the kind you can barely get on because they are so tight.
The loose fitting joiners form a poor connection that puts some resistence in the line, and if power is drawn from a point past this, the current flowing through this resistence will generate heat.
Have you ever had an outlet in your house where the contacts were worn and plugs fit in loosely? The plug on the appliance you have plugged in there gets warm or hot. Or a light switch that's failing, sometimes they make a siggling sound - and get hot. Same principle. In my previous house, I had to replace nearly every receptacle in the place, they all had at least one of the two outlets so loose that plugs would just fall out. Cheap shoddy work. It's where I learned to hate solid wire, pulling the old outlet out of the box, and then trying to push the replacement back in. Especially on middle of the circuit outlets where there were a total of 4 wires.
--Randy
Modeling the Reading Railroad in the 1950's
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rrinkerIt's where I learned to hate solid wire, pulling the old outlet out of the box, and then trying to push the replacement back in.
You will hate it even more if you use stranded wire and a single strand reaches out to touch another, or the metal box. They WANT to do that, you know.
Yes stranded is more flexible, but if the wire is not normally subject to stress, solid is far better.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Electrical concerns are the #1 request for help I see, and many are by very experienced technicians. Lots of people have a hard time with it.
Yes, as long as current is less than the breaker or fuse, it will not trip. And current is dependant on load, which is the locomotive (s).
A true short will open the breaker, so if the breaker is open, no current can flow. No current flow = no heat. Incorrect polarity will open the breaker, unless a feeder is so small as to act like a resistor. And if thats the case, you really do not have a short.
None
Jim
BroadwayLion rrinker It's where I learned to hate solid wire, pulling the old outlet out of the box, and then trying to push the replacement back in. You will hate it even more if you use stranded wire and a single strand reaches out to touch another, or the metal box. They WANT to do that, you know. Yes stranded is more flexible, but if the wire is not normally subject to stress, solid is far better. ROAR
rrinker It's where I learned to hate solid wire, pulling the old outlet out of the box, and then trying to push the replacement back in.
Maybe for house wiring, but I will never use solid for my main power bus. Feeders - yes, but thin solid wire is easy to form and easier to solder to the rail than stranded wire.
Soo Line fan Posted by richhotrain on Thursday, November 28, 2013 5:36 AM I am still trying to come to grips with the notion of heated rails on a DCC layout. Electrical concerns are the #1 request for help I see, and many are by very experienced technicians. Lots of people have a hard time with it. So, what we are saying is that too few feeders can result in heated rails without tripping the booster? Yes, as long as current is less than the breaker or fuse, it will not trip. And current is dependant on load, which is the locomotive (s). Can this only happen with shorts or also on a wiring with correct polarities? A true short will open the breaker, so if the breaker is open, no current can flow. No current flow = no heat. Incorrect polarity will open the breaker, unless a feeder is so small as to act like a resistor. And if thats the case, you really do not have a short. What effect does this have on parked locos on those heated rails? None Rich
Thanks, Jim.
I asked that last question about parked locos because all of my track is powered at all times as long as my DCC booster is powered up. I know that some people cut off power to loco storage tracks, so I just wondered about the effect of heated rails on dormant locos.
My guess would be if the rail isn't so hot it's melting ties, then the trains are OK sitting on it. Of course if it's melting ties and the breaker hasn't tripped, there is a serious problem.
This has been a very interesting topic. Reading through the posts we can see that the OP had a temporary wiring arrangement. Now he has powered the buss and using feeders his problem is being solved.
To expand on this example:
We all have opinions on how layouts should be wired, how many feeders, and whether or no to solder joints etc etc and we all have different experiences and results. The title of this thread shows what can happen when the "conductors" are inadequate.
I am no electrical wizard at all, but I get the basics. A short circuit only shows as a short if the wiring is adequate, if wiring is inadequate (too small, too long, poor conductor, etc) then that same short shows as resistance (load) which results in heat.
I hope this thread is helpful to any DCC newcomers. Lets not have another debate on stranded or solid wires, please.
rrinkerI Do use NEW joiners when I lay each section of track - I have some that have been connected and disconnected many times and they slide on with almost no resistence.
Soldering a loose and sloppy joiner just fills the gaps between the rail and joiner with lead and tin. Lead and tin are not good conductors of electricity. If you are going to solder, make certian there is a good electrical contact with a tight joiner to begin with, then the solder's function is to hold that good connection in place not be the connection.
Texas Zepher Lead and tin are not good conductors of electricity. If you are going to solder, make certian there is a good electrical contact with a tight joiner to begin with, then the solder's function is to hold that good connection in place not be the connection.
That is one of the best explainatioons regarding soldering. Thanks Texas Zepher.
Almost off topic.
Many here not aware of a similar issue that happened in houses where aluminum wire was installed. Where the aluminum wire was spliced to copper wire using wire nuts or outlets, switches, there was corrosion developing. Wire nuts are normal for house installations at many points. Contact resistance. At this point, heat developed and a fair amount of houses burned down. A few amps trying to pass that splice would overheat any wood beams nearby.
I have seen a wall switch panel glowing with a few amps flowing through the spice. Not enough to trip the breaker in the wall panel. Breakers are usually 15 or 20 amps. Same issue with the OP, not enough current to trip the controller but heating up the joints.
Removing all wire nuts , connections and applying a compound developed for dissimilar metals would usually take care of the issue. The OP only had to solder joints which some don't care to do but use plenty of feeders.
The OP's issue was a short down the line with few feeders. Contact resistance. Not enough heat to melt anything which I was sure of. Track heating up could be misunderstood by some.
I use to use silver solder paste. The same solder paste that is used in soldering electronic circuit boards
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
richg1998 Removing all wire nuts , connections and applying a compound developed for dissimilar metals would usually take care of the issue. The OP only had to solder joints which some don't care to do but use plenty of feeders. The OP's issue was a short down the line with few feeders. Contact resistance. Not enough heat to melt anything which I was sure of. Track heating up could be misunderstood by some. I use to use silver solder paste. The same solder paste that is used in soldering electronic circuit boards Rich
If I remember correctly, repair of such hazardous connections by using some sort of compound was not a solution recommended or accepted by authorities. Short of replacement of the wire (branch wiring, not service entrance cable), there were/are a couple of recommended connectors that are used to connect a copper wire pigtail to the aluminum wire. The copper pigtail would then be connected to the receptacle, switch, etc. If you might have such a problem, make sure you research thoroughly what is currently available and acceptable to the authorities. Do not attempt any home-made short-cuts!
Dante
Edit/P.S. Another aspect of the problem was that the aluminum wire expanded and contracted excessively; therefore, connections could loosen.