Re: DCC Wiring - Can it cause a fire?

Mark Gurries
 


On Jan 21, 2014, at 11:52 AM, Robert Morrison wrote:

Good idea about the lighted switch for layout power circuits. I did this at my old home, but not yet at the new one.
Of course, since most of my locomotives have steam sound decoders, there is enough noise to alert me when I leave.
Nevertheless, my next project is to get a circuit with a lighted switch at the entrance to the layout.

I use 20 AWG wire for the drops to every piece of rail, no drop is more than 12 inches long.
Joiners are for rail alignment only.
Main power bus is 12 AWG.
All sections of the layout do trigger the circuit breakers when shorted with a quarter or screw driver.

Excellent.

An idea:
After the layout power is on for a while, go around feeling the wires, especially the drops and solder joints for heat build up.
That might tell you if there is a greater potential for fire.

The only time you will get heat is if there is a short circuit that fails to trip any DCC circuit breaker or booster.   Hence the purpose of the coin short circuit test which makes sure the resistance in the wiring is low enough.

If there is a highly resistive connection somewhere in the wiring that is more than about 2.8 ohms when using a 5Amp booster and there is a short circuit on the track,  that resistive point is where all the heat will be because the booster will not have shutdown but instead deliver full power.


Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com



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