In this post I have a simple tip that I always use when wiring up a layout which can save you hours of head-scratching and frustration.
Although DCC wiring can become complicated, the basic principle that all rail feeder wires are joined together applies. Well, all the left rails together and all the right rails together. Even if you have sections separated with electronics like a Digitrax PM42 Quad Power Manager or different boosters, you’ll still have areas with lots of feeders joining to a common point or bus. The frustration starts when you finish connecting all the feeders and you have a short where something is connecting the left and right rails. The headache starts when you slowly start un-soldering wires or cutting feeders to find the short. It’s guaranteed to be the last one!
To avoid this I use a multi-meter as I work. Just about all multi-meters have a setting for continuity. Some even come with a buzzer which sounds when the probes touch. In the image below you can see I have set my multi-meter to continuity.
I always check the bus for continuity before I start and after I join each wire, or group of wires. If I am working in an area with lots of feeders I sometimes clip the multi-meter to the rails or bus. Then if a feeder with a problem, or the wrong feeder is touched to the bus, it will sound the alarm.
This simple tip has saved me hours of searching and re-working areas.
Some of the common causes of shorts when you’re building a layout are:
Shorts in the frog section of an Electrofrog point/turnout due to no insulating rail joiners being installed.
Shorts in the frog of a modified Electrofrog point/turnout because the jumper wires have not been removed. See my post here regarding how to modify your points for better operation.
Copper strips used to hold the track in place when rails cross base boards joints. If these are not cut in the middle they will short the rails.
And the biggest cause, believe it or not, are tools lying across the track.
Hopefully this will help you have a trouble-free time when wiring up your DCC bus.