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To DCC bus or not

Posted: Tue Feb 11, 2020 9:50 pm
by Spookymooo
I’m about to embark on building my first DCC layout and have read about the idea of soldering dropper wires from each piece of track to a wiring bus....
Why would this be better than soldering dropper wires from each piece of track to the next piece?
Cheers Rob

Re: To DCC bus or not

Posted: Tue Feb 11, 2020 10:30 pm
by Rog (RJ)
It's better to use a bus because the bus wires should have a lower resistance than the track, assuming you use bus wires of sufficient size. Increased resistance can prevent the DCC controller from cutting out if a short circuit occurs, which could lead to track, wiring or rolling stock damage through overheating. Resistance can also lead to slow running.

Re: To DCC bus or not

Posted: Wed Feb 12, 2020 8:56 am
by Paul-H
It may also depend on the layout size. One layout I run on was designed to be busless, its basically a double loop on a 15x4 foot baseboard, and it wired as the OP proposes, with all joints bridged by wire, on that there is no difference in resistance of that short distance and the controllers short protection works fine.

Wouldn't want yo do it on a much larger layout.

Downside to this method is a brake in the track and the whole track dies, unless you feed it like a ringmain.

There are always more than one- way to skin the proverbial ;)

Re: To DCC bus or not

Posted: Fri Feb 14, 2020 9:16 am
by RAF96
If you are relying on the track as the power conductor consider how you get across points, as they essentially act as isolation switches for any track forward of the selected point direction. Do not rely on those Hornby springy point continuity clips to transfer power to anything more than a siding or two.

Re: To DCC bus or not

Posted: Fri Feb 14, 2020 10:34 am
by Brian
Hi
I think you need to answer to yourself the following ...
1) Will the track be frequently lifted and the layout plan changed?
2) How large will the layout be?
3) Is the layout to be more than a loop of track with a couple of sidings?
The answer to these will help determine if a DCC bus pair is needed or not.

IMO on a fixed layout a DCC bus is the very best method of transferring power and data into the rails. The bus connects to the rails with smaller wire either 16/0.2mm or 7/0.2mm equipment wire (You can use 7/0.2 where each piece of track is feed).

Soldering link wires across metal rail joiners (Fishplates) will work, but is very unsightly, as the link has to be soldered on the rails outer web area and is highly visible. Far better is to solder the dropper wires to the rails undersides before track laying. Then via a pre drilled hole (or two holes) the droppers pass down to below baseboard and connect to the appropriate bus pair. When ballasted the dropper wires are then invisible! See this series of nine photos as an example... https://www.brian-lambert.co.uk/Electri ... llery4]/0/

Mod Note: Topic moved to the DCC forum Section.

Re: To DCC bus or not

Posted: Sun Feb 16, 2020 12:43 am
by Spookymooo
Thank you Brian.... a very helpful and comprehensive response.
There will be approx 120 metres of peco code 100 track, essentially a large one down line: up line circuit with several junction points/slips and turntable... as this is my first dcc setups I’ve been reading up about the pitfalls and solutions.
It will be a permanent layout and will not be pulled up in the future ( by me anyway😊)
Thanks for the pics and literature
Cheers Rob