Model Railway Forum banner
1 - 20 of 23 Posts

·
Premium Member
Joined
·
234 Posts
Discussion Starter · #1 ·
I am embarking on building my first layout and I have researched this through reading books and this forum and asking questions as well as going on a DCC course. All of this has been very helpful BUT I have one very basic question......

I understand the need for a control bus and accessories bus but how do you wire the ancillary wires from the track and the accessory decoders into the main bus wires. I can think of a number of ways of doing it but you guys have the experience so please enlighten me and my apologies for such a simple question!

R
 

·
No Longer Active.
Joined
·
13,319 Posts
Generally it is better to run two power bus's - one for the track & one for the accessories, but it really does depend on the size of the layout.

The most important thing though is to use decent sized cable/wire for the bus, soldered joints are preferable.
 

·
Registered
Joined
·
1,080 Posts
Run your bussbar under the layout baseboard. Drill holes through the baseboard where you want the rails or accessory to attach to the bussbar. Use soldered connection to attach the rail or accessory connection to the bussbar.

The term Bus or bussbar is used to signify a main carrier. Feeder is the term for the wire or cable the rail or accessory.

A bussbar in my world is a aluminium or brass bar, that is 15mm by 5mm by 1800mm. They carry +15V or -15V or +28V or +5V for use in on our flight simulators. The size minimises the volts drop to end users, so they all receive the initial voltage.

Majority of problems come about due to dirty connection, loose or bad, on small feeders which can knock, say +5v down to 4V over a 1metre cable length. In logic circuits this may turn a 1 into a 0. Remeber that the resistance to flow increases the current draw and thus the wattage. The total load on the transformer or power supply has to be kept within its limits or it will overheat.

Naturally your buss doesn't have to be that thick 1.5 to 2.5 mm electric cable will suffice.
 

·
Registered
Joined
·
2,150 Posts
QUOTE (randolph @ 13 Aug 2008, 06:53) <{POST_SNAPBACK}>I am embarking on building my first layout and I have researched this through reading books and this forum and asking questions as well as going on a DCC course. All of this has been very helpful BUT I have one very basic question......

I understand the need for a control bus and accessories bus but how do you wire the ancillary wires from the track and the accessory decoders into the main bus wires. I can think of a number of ways of doing it but you guys have the experience so please enlighten me and my apologies for such a simple question!

R

Hi R.
As Brian has said use a separate bus for track power & accessories. Use 32.0.2 wire for the main Track & Accessory buses & 16.0.2 wire for connecting track droppers to the main track power bus & accessories to the accessory bus.



For reliable track power connection solder 16.0.2 wire droppers to every piece of track or at least every 36"of track. These droppers can be up to 300mm or 12" in length. There are various ways to do this. Solder, Choc box connectors or T Splices.



Solder seems to be the most popular way of connecting. There are tools available which grips the bus wire & spread the insulation apart about ½" without cutting the cables. These tools are not expensive.

Strip the insulation from the end of your dropper wire & wrap around the exposed main bus wire. Solder this joint using a good hot iron. You can then slide the main bus insulation back up against the solder joint. If you are not comfortable with a soldering iron practice on some scrap wire or track before you begin.



The other ways of connecting your dropper wires to the main bus wires are self explanatory but if you need help just ask. If I have forgotton anything I'm sure there are plenty of people here who will put me right. The main thing is take your time & enjoy it.

Also there are no stupid questions, only the ones you don't ask.
 

·
Premium Member
Joined
·
6,201 Posts
QUOTE (TonyDaly @ 13 Aug 2008, 09:04) <{POST_SNAPBACK}>Solder seems to be the most popular way of connecting. There are tools available which grips the bus wire & spread the insulation apart about ½" without cutting the cables. These tools are not expensive.

Hi Tony,

Have you a link to a supplier of the tool mentioned for spreading the bus wire please ?

Thanks.
 

·
Registered
Joined
·
827 Posts
QUOTE (upnick @ 13 Aug 2008, 09:25) <{POST_SNAPBACK}>Hi Tony,

Have you a link to a supplier of the tool mentioned for spreading the bus wire please ?

Thanks.

Automatic wire strippers, Rapid Electronics part number 86-0390 @ £5.30+VAT

Andrew Crosland
 

·
Registered
Joined
·
2,150 Posts
QUOTE (upnick @ 13 Aug 2008, 09:25) <{POST_SNAPBACK}>Hi Tony,

Have you a link to a supplier of the tool mentioned for spreading the bus wire please ?

Thanks.

Andrew beat me to it. I got mine here where I live in Southern Ireland.There not expensive but great value.
 

·
Registered
Joined
·
2,151 Posts
QUOTE (SPROGman @ 13 Aug 2008, 10:34) <{POST_SNAPBACK}>Automatic wire strippers, Rapid Electronics part number 86-0390 @ £5.30+VAT

Andrew Crosland

The problem with these are that if you do not adjust the diameter correctly you can cut off a couple of copper strands too.
I would go for the T-Splices, without cutting the cable.

Baykal
 

·
Registered
Joined
·
2,150 Posts
QUOTE (ebaykal @ 13 Aug 2008, 11:37) <{POST_SNAPBACK}>The problem with these are that if you do not adjust the diameter correctly you can cut off a couple of copper strands too.
I would go for the T-Splices, without cutting the cable.

Baykal

Hi Baykal.
I think you may be thinking of a different type which has a single screw which allows you to adjust the diameter of the jaws.
The one I have in mind was made by Skult & comes with the cutting plate fitted with different diameter cutters which go from 1mm to 3.2mm. You just put your cable in the correct size and close the jaws. It will also strip the ends of cables.
I use the t splices & find them great.
 

·
Registered
Joined
·
2,150 Posts
QUOTE (upnick @ 13 Aug 2008, 09:25) <{POST_SNAPBACK}>Hi Tony,

Have you a link to a supplier of the tool mentioned for spreading the bus wire please ?

Thanks.

Hi Upnick.
Here is a link to a picture of the tool I have. It's not the same name but it is exactly like mine.My one has yellow handle grips & has the name Skult on one of the handles.B & Q or some store like that should have one.A company that supplies the electricial trade should certainly have it.
http://www.specialized.net/ecommerce/shop/...ipmaster-45-091
 

·
Premium Member
Joined
·
6,201 Posts
QUOTE (TonyDaly @ 13 Aug 2008, 13:42) <{POST_SNAPBACK}>Hi Upnick.
Here is a link to a picture of the tool I have. It's not the same name but it is exactly like mine.My one has yellow handle grips & has the name Skult on one of the handles.B & Q or some store like that should have one.A company that supplies the electricial trade should certainly have it.
http://www.specialized.net/ecommerce/shop/...ipmaster-45-091

Hi Tony/Andrew,

Thank you for the information a trip to B&Q for some i think.
 

·
Registered
Joined
·
75 Posts
A really cheap and reliable bus bar is a piece of cheap HO track..mounted under the baseboard..already finished and insulated??
Phil
 

·
Just another modeller
Joined
·
9,983 Posts
QUOTE (philg @ 13 Aug 2008, 23:23) <{POST_SNAPBACK}>A really cheap and reliable bus bar is a piece of cheap HO track..mounted under the baseboard..already finished and insulated??
Phil

***Good for a control panel yes, but not for a layout bus.... this would result in droppers that are long on anything other than a shunting plank type layout.

a layout bus should ideally follow the main rail layout above the board with branches where neeed to accommodate yards and branch lines etc. and Power should be fed to the track via droppers that are not more than say 300mm... providing they are kept to this length then finer wire is OK.

It should ideally be 32/.2 for a small to medium layout, larger for a biggish layout - and much, much larger for a very big one - up to the equivalent to 10 gauge or about 3mm diameter copper (about 9sq mm).

Unless you have a layout larger than the average garage, 32/02 will be fine, so most need never worry about larger gauges.

None of this is about current carrying ability.... as mentioned earlier by railstimulator, its all about avoiding voltage drop under load.

The bus should either be twin wire twisted about 4 turns per foot or two separate wires not less than 100mm apart. Close wires that are not twisted will create an inductance when the power bus is under load that will both greatly increase voltage drop and significantly distort the DCC waveform.... not a problem on a small layout but as size grows, the effect becomes a real problem.

The worst bus is that B awful copper tape ZTC push ...It often gets placed either side of a bit of 2x1 to keep it tidy and when its done like that it makes a hugely inductive power bus thats really just a long capacitor, and layouts using it should like that should both terminate the bus and also restrict each bus length to no more than 2 or 3 metres per section to avoid problems...

regards

Richard
DCCconcepts.
 

·
Registered
Joined
·
827 Posts
QUOTE (ebaykal @ 13 Aug 2008, 12:37) <{POST_SNAPBACK}>The problem with these are that if you do not adjust the diameter correctly you can cut off a couple of copper strands too.
I would go for the T-Splices, without cutting the cable.

Baykal
Did you actually bother to look at the link I gave?

Andrew
 

·
Premium Member
Joined
·
6,201 Posts
A trip down the cellar for some balsa for the the layout proved fruitful as i found my strippers like those Tony as i was under the impression i had left them at my old house when i moved when i saw them in the link i cursed they had been left ........ but all set now with them for the bus
 

·
Registered
Joined
·
2,150 Posts
QUOTE (upnick @ 13 Aug 2008, 19:56) <{POST_SNAPBACK}>A trip down the cellar for some balsa for the the layout proved fruitful as i found my strippers like those Tony as i was under the impression i had left them at my old house when i moved when i saw them in the link i cursed they had been left ........ but all set now with them for the bus


The best tool anyone could have for wiring a layout. Make sure you use the correct size cutter for your wire.
 

·
Premium Member
Joined
·
234 Posts
Discussion Starter · #17 ·
QUOTE (ebaykal @ 13 Aug 2008, 11:37) <{POST_SNAPBACK}>The problem with these are that if you do not adjust the diameter correctly you can cut off a couple of copper strands too.
I would go for the T-Splices, without cutting the cable.

Baykal

Thanks for all your answers which are very helpful - but what is a T splice?

R
 

·
Registered
Joined
·
2,150 Posts
QUOTE (randolph @ 14 Aug 2008, 07:06) <{POST_SNAPBACK}>Thanks for all your answers which are very helpful - but what is a T splice?

R

Hi R.
Look here. The one which you look at is the centre Blue splice which clamps on to the 32/0.2 main bus cable. You then clamp the Red spade connector on to the 16/0.2 dropper wire which clips into the Blue splice connector. If you use these it is important to fit them correctly with a Crimping tool. Some people frown upon them but I find them very easy to fit & use.

http://www.rapidonline.com/Cables-Connecto...e-splices/63979
 

·
Premium Member
Joined
·
234 Posts
Discussion Starter · #19 ·
QUOTE (TonyDaly @ 14 Aug 2008, 09:11) <{POST_SNAPBACK}>Hi R.
Look here. The one which you look at is the centre Blue splice which clamps on to the 32/0.2 main bus cable. You then clamp the Red spade connector on to the 16/0.2 dropper wire which clips into the Blue splice connector. If you use these it is important to fit them correctly with a Crimping tool. Some people frown upon them but I find them very easy to fit & use.

http://www.rapidonline.com/Cables-Connecto...e-splices/63979
That's brilliant, thanks Tony

R
 

·
Registered
Joined
·
2,151 Posts
QUOTE (SPROGman @ 13 Aug 2008, 20:17) <{POST_SNAPBACK}>Did you actually bother to look at the link I gave?

Andrew

Yes I did Andrew, and it is a totally different gadget, not the one I was mentioning about. Checking the hardware stores locally if it is available.

Baykal
 
1 - 20 of 23 Posts
Top