Track & Wire Properties
This is a purely educational section for those who want to know more about why the rules of layout wiring are what they are for large layouts. To see those rules, go here:Wiring Planing
Do you need to know this stuff to enjoy DCC....NO. But if you curious and want to learn more, keep on reading for this stuff about wires is not magic once you understand what is happening.
Why is this even a topic?
Because some large layout are experience electrical problems and they do not understand what is going on. What are the problems? Loss of decoder control, Locomotive decoder losing programming or worse blow up in smoke, occupancy detection problems, unreliable accessory decoder control. Knowing what is going on is half the battle to finding the solution.
When layouts ran on DC, electrically life was simple when it came to dealing with wires regardless of the size of the layout. Simply choose the largest wire gauge you need to make sure the voltage drop (losses) in the wire were acceptable.
When we use these very same wires with DCC, they must now conduct a form of AC. See DC versus DCC for more information about DCC's AC power.
AC brings out MORE electrical properties of conductors that were always there but now come into play. These properties can make themselves known when dealing with inconsistent short circuit performance, failing current based track occupancy (signal) detection circuits and decoders losing their programming if not going up in smoke. Buy understanding these proporties, we can design our wiring to minimize them such that we maximize the operational reliability of the layout.
Track or Wires, both are conductors of electricity or current and as such can be treated interchangeably in this discussion.
The Electo-Physical Laws or Properties of Wiring
I will be using the KISS (Keep It Simple Stupid) principle here when I talk about these properties. My goal here is less about technical accuracy and more about getting a feel about these properties.
When current flows down a wire and/or voltage is present on a wire, there are 5 physical properties or effects that can come into play.
PROPERTY UNITS OF MEASURE
1) Wire Resistance Ohms
2) Wire Magnetic Fields Gauss or Tesla's
3) Wire Electric Fields Volts/Meter
4) Wire Inductance Henries
5) Wire Capacitance Farads
If you wish to understand more about these properties and what they mean and in what form can we see them in, go here: Electrical Properties
This section talks about how each is present in our layout wiring.