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I'm new to DCC and have been following some of the threads concerning power buses and feeds. Most discussions seem to mention the use of stranded wire, but I think solid may have better conductance and might even be easier to use, especially when soldering feeders to track. Aside from its relative lack of flexibilty, are there any reasons why it can't or shouldn't be used?
form a pure electrical view as I dont have DCC braided wire offers bedder low voltage conductivity because electricity travles on the outside edge of a wire. you get a more constant flow of power and voltage, also with a little less resistance as there are more paths for the wire to follow. It is easier to solder but a good pair of linesman pliers and you can make a nice tight twists on braided to make it easier to solder to the rails. I'll let some one for the DCC said of it add.
As Drew said, stranded wire does have more paths (larger surface area) for current to follow, thus higher current capacity for the same gauge size. However, I wouldn't be overly concern with this in our hobby with or without DCC. It mostly comes down to personal preference on what you want to work with. I like 12 or 14awg solid for my bus wire, mostly because it can be formed/shaped up and down and around corners and being stiff, prevents sag. I also find it easier to solder a track feed to it since it is stiff and holds in place while soldering. The resistance consideration is almost negligible. If my memory serves me, 12awg solid is only about 4 ohms per 1000feet.
My track feeds are both stranded and solid 22awg; simply depends on what I have on hand. Both work well and again, it depends on what you find easiest to work with. With many feeds on your track, there is not that much current through any single feed. It is paralleled and distributed through all.
Sorry, fellas, but I don't buy the electrical path theory posited above. If it were true, we'd have hollow wires to improve electrical flow many times over. Never seen such an animal, and don't expect to.
The electrons flow from atom-to-atom, and there are gazillions of them across the wire mass. More cross-section = more atoms = more electron flow. At least, that seems to be the rule with DC current. I understand that with very high frequency AC current, there is such a thing as "skin effect", and maybe this is what you fellows mean. I would not expect 60 cycles to be deemed a high frequency.
look at all you heavy lines all braided wire. Yes power flows over the atoms but has much less resistance on the out side of the wire there for a bulk of the current it transmitted over the outside of a wire. Its what I've been told by both professors and the electricians I've worked with.
They're right on this one selector. Stranded wire does have more surface area and current does travel on the outside. This results in more flow and less voltage drop. It really doesn't matter with DCC although stranded wire is also more flexible and easier to work with.
Wow! these discussions go pretty deep. Dc current (not voltage) takes path of least resistance. Consider a piece of circular solid copper wire. As the diameter increases measured from the center, the further out from the center of the conductor, there are more free electrons and present the least resistance to the current flow. There is current in the center however it's value is inversely proportional to the square of the diameter
Layman terms = decreasing the diameter by 1/2 will result in 4 times less current, so based on that rule the majority of current flows on the greatest diameter which is the outside.
Now having said that we will turn to AC (DCC has an AC component but it's not affected by the following)
As the AC frequency increases even more of current flows along the outside the inside becoming too resistive. When the frequencies reach micro wave wavelengths, all the energy travels along the outer diameter. So saving on materials the wave guide (a hollow tube was built) these things still blow my mind.
Anyway consider voltage as the pressure (like when you turn on a water tap) and the flow as the current to do the work.
It's been a long time I've forgotten most of it now.
Cheers
Willis
The suggested gages of wire for the currents you have will be more than adequate. If you have to worry about the surface conductivity issues, you've grossly undesized the wire and you'll have bigger issues. The difference is seen in the lab, not on a model railroad.
I use stranded wire exclusively for one simple reaons - you've got to attach those little buggers together somewhere. Whether you're using suitcase connectors, Posi-Taps, or soldering, it's much easier to get a good electrical connection, since the stranded wire does you give you more surface area when it's flattened out. I find it's easier to solder stranded wire if it's twisted together but not too tight. The solder seems to flow better into the little voids and the joint is mechanically and electrically more sound. The final advantage is size. If I have #16 gauge wire, it's easy to make the wire connection a #22 gauge with some sharp manicure scisors. With solid wire, the wire size isn't very easly changed.
I've been using 14ga. stranded wire for a buss for many years & 22 to 24ga. solid wire for drops. I solder everything. My drops are every 4ft. I don't use any type of a connector except solder. I also use a type of solder that the telephone guys use, which is real hard to find in the electrical stores.
The suggested gages of wire for the currents you have will be more than adequate. If you have to worry about the surface conductivity issues, you've grossly undesized the wire and you'll have bigger issues. The difference is seen in the lab, not on a model railroad.
Ken, you hit the nail right on the head..... For our purposes it makes absolutely no practical difference which you use. Most of the time I prefer to use solid. Some wiring is easier done with stranded. It is whatever the modeler prefers, and what may be available when you are buying it. I end up using both.
Thanks for taking the time to reply and inform me.
