Posted by: bgtwindad | August 28, 2010

DCC Bus installed


IMG_0473

Originally uploaded by BGTwinDad

This evening, I installed the main DCC bus underneath the layout. One of the nice things about an HCD layout is the ease with which you can tip it up and get at the underside for wiring work.

I installed seven large barrier terminal strips. Six are distributed evenly around the layout to provide connection points for the track feeder wires, and the seventh serves as the central point of a “star” topology. The feed from the booster comes into the seventh strip, and cables spread from that strip to the other six.

I used 18ga. x 8 wire solid thermostat wire for the bus. Some may say that this is too small gauge for this bus, but I believe it will be OK, especially given the short runs. The white and black conductors will carry the DCC +/- signal, while the other six provide expansion for DC and DCC accessory power.

The photo above is the central master terminal strip. The brown cable entering from the top is the feed from the DCC Booster. This will go to a 4-pin fascia-mounted socket, and I will make a cable with mating plug for the booster to connect. There are only 5 cables exiting because the sixth terminal strip is daisy-chained from the terminal strip that happens to be in the same “region” as the master connector.

Now that this is in place, I will be able to connect feeders from the track as I install it. With a simple DC controller, I will be able to test connectivity and run trains while saving up for a Digitrax Zephyr.

Above is a “wide shot” of the complete bus system.

The installation was simple.  I used #4 wood screws to mount the terminal strips to the underside of the layout, I cut the cable to length with a heavy duty wire cutter, and removed 1 inch of the outer sheath with a utility knife (carefully!). In then folded the other six conductors back out of the way, stripped 1/4″ of the ends of the white and black wires, and crimped spade terminals to their ends.
I then simply routed the wire to the other terminal strip and repeated the stripping and spade-lug installation process.

To make the jumper wires for the master terminal, I cut another length of the thermostat wire and pulled the black and white conductors free. I then bent it to shape, creating a loop where each screw terminal would be located. After carefully stripping bare the wire in each loop, I simply removed the corresponding screws on the strip and ran them through the wire loops, screwing them in place on the strip.

I will probably go back and replace this jumper wires with neater ones made by crimping short lengths of wire into spade lugs.

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