How many droppers from a single bus connection?

[34theletterbetweenB&D]

How do you put a twist into the bus pair if they are uninsulated?

I don't.  Ask yourself the question 'how do you put a twist in the rails?'. There's no manifest signal problem as a result, with typically twelve locos running at one time on a system with 2 x 15 meter bus and ten times that amount of track length to date; so I would conclude that there is no need to twist the bus.

[Guest]

Possibly a daft question here... but why do people twist the bus wires? Can I assume there is some advantage to this? I'm curious because I have never done so and haven't noticed any adverse effects even over a long run. I normally run the bus wires in parallel to each other, as seen below running left to right.

 

 

 

[Revolution Mike B]

Interesting reading through the replies to the OPs post.

 

My layout is the same size as Mick's (Newbryford) and I've got one continuous bus linking 10 boards, with every piece of track having droppers soldered to the underside of the rail, and in turn, soldered to the bus wires. I've used heat shrink over the soldered joints as mentioned in an earlier reply.

 

 

That's probably not the best example of my work but it hasn't caused any issues so far.

[RFS]

Possibly a daft question here... but why do people twist the bus wires? Can I assume there is some advantage to this? I'm curious because I have never done so and haven't noticed any adverse effects even over a long run. I normally run the bus wires in parallel to each other, as seen below running left to right.

 

plank_009.jpg

 

See an explanation here - https://sites.google.com/site/markgurries/home/dcc-general-best-practices/wiring-planing/twisted-pair-wiring

 

Personally I haven't bothered - I use 2.5mm solid copper wires from household "twin and earth" cable and twisting them would a) be quite difficult and b) make connections difficult too. In my view any advantages are small and easily outweighed by the disadvantages on the average DCC layout. My wires run parallel down the centre of the boards, approximately 4 inches apart. 

Edited January 16, 2018 by RFS

[newbryford]

There are so many "best practice" things that can be done for DCC - such as twisted bus wiring.

Yet many layouts still work quite adequately without any best practice being followed.

 

Twisting is there to minimise noise etc  when compared to parallel conductors, but in the case of a model railway, you can't get much more parallel than a pair of rails................

 

Cheers,

Mick

[wandering blue]

There are other alternatives...

 

These are great, strip the wire, lift the lever, insert wire, close the lever.  They will accept a much wider range of wire sizes and come in two, three and 5 way and you can use them over and over.  The only down side is that they don't have a through connection.  It simply commons all the wires together.  I've used them and never had a problem.

 

Screen Shot 2018-01-12 at 17.52.02.png

 

Those are Wago connectors. Use a red or blue evil clip, ie Scotchlok or other IDC, to spur off the bus, then a wago to make multiple close dropper connections. As you say, Gordon, the only downside is a lack of a through route, so if used on the bus, you would have to sever the bus cable. If used on spurs, reduces the number of IDCs on the main bus in fiddle yard environments, or would have done, if I’d known about them beforehand....

[tractor_37260]

What's the options for connecting the main Bus cables between removeable boards ?

 

The DCC Concepts bus/dropper tags look very useful need to get some of those......

[gordon s]

Wago have updated their lever connectors and now both designs are available.  The new design features a flat lever and is a lower profile.  2, 3 and 5 way again.

 

 

This also an option.  This time you strip the wire and just push in.  To my mind they are more suited to solid strand wire.  They say you can still get a cable out if something goes wrong.

 

Edited January 16, 2018 by gordon s

[Butler Henderson]

I considered the Wago lever connectors but went with the In-Sure ones (rated at 24A) as they cost less for example 30 Insure 5 ways are £13 at Tool Station. Each connection will take 32/0.2 cable or 2 x 16 /0 2 cables or 4 (or maybe 5) x 7/0.2 cables

Edited January 16, 2018 by Butler Henderson

[Enterprisingwestern]

What's the options for connecting the main Bus cables between removeable boards ?

 

The DCC Concepts bus/dropper tags look very useful need to get some of those......

 

As bus wire is fairly hefty, over here I'm using household 2 pin plug and socket connectors, about a quid a pair in the chino supermercado, don't know whether I'd trust them on 220 volts though!

 

Mike.

[Phil S]

Not the best of ideas to use a connector of a type normally used for mains electricity for low voltage connections - someone, especially at a show might make a mistake !  Its like having mains voltage as part of the layout boards - it may have been okay for Wartime Hornby 0 Gauge along with a series mains bulb (transformers not being of any use in all places at the time because the national grid with ac mains was not in place - I even recall some TVs as dc powerable - and I don't mean portables)

 

There are plenty of options for Low Voltage High Current connectors - eg the audio industry gives us Cannon XLRs - but don't forget the car industry with their wiring harnesses full of 'unique' polarised connectors which cannot be plugged into the wrong socket nearby.  Many of these use convenient spade terminals for construction, and the housing can easily have its 'locking pin' trimmed back to allow easy disassembly at the end of the day

 

For simple commoning connections I also use WAGO lever-closure Commoning locks in 2s 3s and 5s for bus distribution - a tool-free maintenance option. . the types are use are readily available from Screwfix in boxes and quite cheap - also the wires are releasable when YOU want  - unlike the other push-in and lock style.

Edited January 16, 2018 by Phil S

[WIMorrison]

Is previous last post to this somewhat contradictory between the first and last paragraphs?

 

Sure seems that way to me

[Butler Henderson]

Is previous last post to this somewhat contradictory between the first and last paragraphs?

 

Sure seems that way to me

I read it as firstly referencing the post immediately above it, the not lever connectors in the last.

[WIMorrison]

Starting with;

 

...Not the best of ideas to use a connector of a type normally used for mains electricity for low voltage connections ...

 

Followed later by;

 

...For simple commoning connections I also use WAGO lever-closure Commoning locks in 2s 3s and 5s for bus distribution...

 

Suggest a total contradiction given that in the first para it isn’t a good idea to use mains connectors to wire the layout, then in the last para highlighting the use of WAGO connectors for the common connections - WAGO are the very main connectors being berated in the first paragraph:(

[Butler Henderson]

Suggest a total contradiction given that in the first para it isn’t a good idea to use mains connectors to wire the layout, then in the last para highlighting the use of WAGO connectors for the common connections - WAGO are the very main connectors being berated in the first paragraph:(

Not the Wago connectiors but the " I'm using household 2 pin plug and socket connectors, about a quid a pair in the chino supermercado, don't know whether I'd trust them on 220 volts though!"

[newbryford]

I've started using 4mm banana plugs/sockets for DCC bus connectors between boards. They have a high current capacity, typically 10Amps for good quality ones.

 

 

We have two track buses - one for the outer circuit, one for the inner. This arrangement is between nine baseboards.

Simple colour coding - if someone plugs it in wrong, the loco shorts when we test. The person responsible for plugging it in the wrong socket gets a good kicking  the urine taken out of him by fellow club members....

Simples

 

The multipin socket carries the lower power rated accessory only bus and a 12v DC feed for building lights etc, as well as four spare coresif we ever need them. The multipin connectors are Maplin and the 4mm plugs are Ebay

DCC Concepts bus tags are also used.

 

Cheers,

Mick

Edited January 16, 2018 by newbryford

[wandering blue]

What's the options for connecting the main Bus cables between removeable boards ?

The DCC Concepts bus/dropper tags look very useful need to get some of those......

Lots of options, a search on here and the internet will bring up everything from simple push-fit choc-blocks, to numerous audio or data connectors. As the number of wires on DCC is typically much less then for analogue, I settled on Anderson Powerpoles. Dim ‘under baseboard’ shot attached. These are designed for breaking under current and crimp onto cable ends. I’ve made 2gang pairs. One side is secured through extra slot fittings, offset from the baseboard surface by connector blocks. The other pair is over-sleeved and passes through the board joints. The variety is huge, the number of gangs and possible configurations likewise.

[Crosland]

Twisting is there to minimise noise etc  when compared to parallel conductors, but in the case of a model railway, you can't get much more parallel than a pair of rails................

 

It's the spacing that matters, not parallelism. The fact that rails are parallel is irrelevant to the twist or not to twist debate.

[kevinlms]

It's the spacing that matters, not parallelism. The fact that rails are parallel is irrelevant to the twist or not to twist debate.

The reason that the twisting is not critical for DCC, is that the wave forms are fairly slow. Computer network cables for instance, using Cat 5e & Cat 6 are much faster & basically don't work without the twist (for noise cancellation, as others have mentioned).

[Longhaireddavid]

So how do you conveniently and easily strip a section of insulation out of a run of bus cable every few mm and twist it to make a connection?

 

Mike.

 

I use two strips of  10mm copper self adhesive tape as the bus and then solder droppers to those. 

David

[Nigelcliffe]

I use two strips of  10mm copper self adhesive tape as the bus and then solder droppers to those. 

David

 

Oooh its over half way through January so, can we do the annual "does the resistance of copper tape make it unsuitable as bus wire"  thread now please ?

 

( And after all the theory on resistance of copper tape,  the practical answer is:  for long runs, copper tape has surprisingly high resistance compared to decent multi=strand wires, so its far from "best practise" as bus wire.   But, for shorter runs its fine.   ). 

 

 

- Nigel

[Crosland]

Oooh its over half way through January so, can we do the annual "does the resistance of copper tape make it unsuitable as bus wire"  thread now please ?

I can't be bothered but I'm sure my previous posts can be found

 

( And after all the theory on resistance of copper tape,  the practical answer is:  for long runs, copper tape has surprisingly high resistance compared to decent multi=strand wires, so its far from "best practise" as bus wire.   But, for shorter runs its fine.   ).

I have some 1" wide copper taps that is much better than the stuff sold for lighting doll's houses, but I still wouldn't use it for DCC.

[tractor_37260]

I can't be bothered but I'm sure my previous posts can be found

 

I have some 1" wide copper taps that is much better than the stuff sold for lighting doll's houses, but I still wouldn't use it for DCC.

 

I'd agree - I'd use re-cycled  if possible ? stripped household mains T & E with all joints/droppers soldered....  resistance then being negligible..............

[Sir TophamHatt]

If I wanted to wire up all parts of a insulfrog point, so three blue wires and three red wires, that go from the track to a blade connector (red or blue), which is then in the scotchlok connector connected to the bus wire, is that dangerous or just not best practice?

 

Surely the resistance would be barely noticable than if they were all individually attached through scotchloks to the bus wire?

 

I guess the only point of resistance would be the blade connector.

 

Cheers

Edited January 23, 2018 by anotheruser

[tractor_37260]

If I wanted to wire up all parts of a insulfrog point, so three blue wires and three red wires, that go from the track to a blade connector (red or blue), which is then in the scotchlok connector connected to the bus wire, is that dangerous or just not best practice?

 

Surely the resistance would be barely noticable than if they were all individually attached through scotchloks to the bus wire?

 

I guess the only point of resistance would be the blade connector.

 

Cheers

 

Where ever possible a soldered joint will always be a better, long term solution..........although quick and convenient, over time scotchlok connectors can suffer from increased resistance being open to the air/environment etc