#### Re: Wiring a Helix for DCC

Vollrath, Don <don.vollrath@...>

Brian, An ideal connection is to have a track bus feeder about every 6 ft. What I might recommend is …

Run a sub-bus up/down along one of the uprights. 14-16 AWG

Add track feeders to the sub bus at each circular pass of the spiral.

Solder the track joints in the spiral for alignment and continuity.

Leave plenty of space gaps in the rails at top and bottom for expansion/contraction.

But with an approx. 33 inch outside radius, the rail length on each turn will be ~17 ft long…. Or about 8+ feet from the nearest outside upright and track feeder. There is no need to follow the track along the spiral with an electrical wire, but if you are overly concerned, providing a second sub-bus and connecting to each set of rails at each pass on an opposite upright will double the electrical connections and reduce the electrical path to the nearest feeder to be less than 5 ft. A little on the side of overkill.

DonV

From: w4dccqa@groups.io [mailto:w4dccqa@groups.io] On Behalf Of Brian Eiland
Sent: Thursday, June 07, 2018 1:10 PM
To: w4dccqa@groups.io
Subject: [w4dccqa] Wiring a Helix for DCC

I've seen a few references that suggest it is NOT necessary to run the bus-lines along the track route in a spiral helix, but rather just run the track feeders lines down one of the vertical legs (post) to the bus wires at the bottom. I thought this was a good idea.

My question is how many of these vertical connections should be made?

My helix is a double track affair with radii of 32.5” and 29.5”. I have plans to stagger the rail joints, and to solder all the rail joints,...code 100 Atlas rail.

Considering this sort of relatively small radius/circumference, I'm thinking I need only one feeder set of wires for each elevation/loop of the helix. And perhaps these feeders wires might be sized a bit larger than normal??

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