Jump to content

Bus Wiring - Missing the obvious...


Recommended Posts

Hi guys, sorry about this, I've searched here and google, and watched several Youtube videos but still un-sure. Happy to be directed to relevant thread/video for dummies that I've not yet come across.

 

I want to do a bus underneath the baseboard to aid running, at the moment it's a 5'x4' loop. I plan on doing it initially for DC, only the loops and leaving sidings out for now and relying on point blade contact, to allow opportunity for swapping locos out of sidings etc, not doing isolating sections at this stage or ever if I can help it. Eventually I'm all but sure I'll go to DCC, at which point I can add in the sidings to the bus wire to make everywhere live all the time (correct me if I'm wrong on the last couple of sentences).

 

So far what I've bought is some 7x0.2mm (IIRC) wire for the droppers from each piece of track, and some flex cable (3x 1.5mm2, says suitable for electric fan ovens etc, so assume similar to mains cable as mentioned in several places). Unless I've made some mistake so far that would lead to disaster, I moved on to looking at how to join it all up, which is where confusion set it. I came across a number of methods and from my non-electrician mind none seemed ideal. Cable lock connectors came up, these are easy to use however seem like you're cutting into the wire you join on to. Female/male spade connectors, I have a suitable crimping tool but I can't picture how a circuit works in practice e.g. droppers have male connectors on, do you end up with a separate wire to each with a female connector, which are all combined into a single wire into the controller? Or do you wire one dropper to the next and in effect not have a separate wire that they join on to. I looked at soldering although nobody seemed to do this in videos, I would have assumed you strip the bus, solder the dropper, move on to the next one. I've tried soldering to the bottom of rails which I was fine with and I'd have a go at joining the other end to the bus, just wondered why it doesn't seem the method of choice with the youtubers?

 

So there it is, recently I've started just trying things out and learning from mistakes rather than coming here with any little query, but with electrics I thought better of it. Some of the videos are helpful but none seem to give a full picture, last night I watched two or three of Chadwick Valley to do with wiring which were all one or two stages of complexity upwards, looking at various boxes and circuit boards. A couple of others showed the connectors that you just squash a blade through with pliers but as mentioned, to me that seems like it is cutting through the wire and weakening it or not giving a completely reliable connection, although it's simplicity does appeal. I'm also unsure on my initial perception where the bus wire is continuous and the droppers join it periodically, or is it just as effective to be cut into sections and wire it from one dropper to another in effect (daisy chain?).

 

Many thanks, if what I've said isn't a full picture then apologies I'll gladly update

Link to post
Share on other sites

Red IDC connectors (Scotchlok) are the correct size for the wires you suggest and they will work perfectly - they cut the insulation nit the wire, hence being called an Insulation Displacement Connector - IDC :)

  • Agree 1
  • Thanks 1
Link to post
Share on other sites

Wago 221 (or similar) connectors are by far better than Scotchlok IDC connectors, but are more expensive, if soldering wires isn't you for you - though IMO soldering is the best of all.

Three or five way Wago connectors would usually be the type you need.  Note each Wago connector has all its connections commoned together, so one is used for one bus wire and another for the second bus wire.  You can strip two or three dropper wires and twist them together and insert into one Wago tube. So for example your red bus wire comes into the Wago on one tube, goes out to further around the layout via another tube of that same connector and the remaining tube or tubes are used for droppers fed from that bus wire.   Example... Wago connector example    

An alternative and much cheaper is to use cut up pieces of terminal block connectors and link across all one side of that block.  Usually terminal blocks are supplied in 12 way strips so you can have 2, 3 4 or whatever ways you want and by just link one side and using the other side for connections.  Or use a bare strip of copper wire and twist and solder droppers onto this small link (See image link)

Link to terminal block connectors  This give the  very basic idea... Link to example-1   Image link

 

You may find some useful information here too....  Link to my web site DCC section 

Edited by Brian
URL to link added
  • Thanks 1
Link to post
Share on other sites

There are a number of ways to choose from. I use Wickes terminal blocks which are located around the layout at places where I need droppers. I reckon I can get 20 or so droppers from a single terminal block. The main BUS is simply fed through the block with the wire bared and screwed into the block so that it makes contact. 

 

A8784F2E-0318-463C-9608-DF47C9DF7030.jpeg.b117592a1e49b7c400461d1569f24210.jpeg

  • Thanks 1
  • Informative/Useful 1
Link to post
Share on other sites
  • RMweb Gold

The all metal blocks pictured above are often referred to as Earth blocks rather than terminal blocks.

  • Agree 2
  • Thanks 1
Link to post
Share on other sites

I’m using these spaced around a largish layout. Track bus wires go in one end and then carry on from the other end to the next block. Top connections are connected to one (say inner) rail and bottom connections to the other (say outer) rail around the layout.

 

4BCC8C6E-732B-4E3E-8BBD-481EF6886470.jpeg

Edited by RAF96
More info
  • Thanks 1
  • Informative/Useful 1
Link to post
Share on other sites
  • RMweb Gold
2 hours ago, RAF96 said:

I’m using these spaced around a largish layout. Track bus wires go in one end and then carry on from the other end to the next block. Top connections are connected to one (say inner) rail and bottom connections to the other (say outer) rail around the layout.

 

4BCC8C6E-732B-4E3E-8BBD-481EF6886470.jpeg

 

RAF96

This looks interesting, where do you get them from?
Steve

  • Thanks 1
Link to post
Share on other sites
18 hours ago, RAF96 said:

I’m using these spaced around a largish layout. Track bus wires go in one end and then carry on from the other end to the next block. Top connections are connected to one (say inner) rail and bottom connections to the other (say outer) rail around the layout.

 

4BCC8C6E-732B-4E3E-8BBD-481EF6886470.jpeg


The distributors website says they are good for up to 48V but the 1K current limiting resistor for the indicator LED suggests it is set up for 12V.

 

Richard

  • Thanks 1
Link to post
Share on other sites

Thank you all very much for the replies, didn't expect so many.

 

On 21/03/2020 at 19:32, WIMorrison said:

Red IDC connectors (Scotchlok) are the correct size for the wires you suggest and they will work perfectly - they cut the insulation nit the wire, hence being called an Insulation Displacement Connector - IDC :)

 

I had a quick look at scotchloks (helpful to have the correct name now) and these seem quite cheap and easy to install, which is over-riding my previous apprehension. Do you have a link to a specific example please? Those I saw had a drop down for colour without indicating any other difference, if 'red' is to do with the size of the wire that will pass through etc. These Scotch Locks (ebay) are an example I came across, is it just wire cross section I should be interested in or are there other considerations such as maximum amp/volts (sorry, electricity is not my strong point).

 

On 22/03/2020 at 16:08, Brian said:

Wago 221 (or similar) connectors are by far better than Scotchlok IDC connectors, but are more expensive, if soldering wires isn't you for you - though IMO soldering is the best of all.

Three or five way Wago connectors would usually be the type you need.  Note each Wago connector has all its connections commoned together, so one is used for one bus wire and another for the second bus wire.  You can strip two or three dropper wires and twist them together and insert into one Wago tube. So for example your red bus wire comes into the Wago on one tube, goes out to further around the layout via another tube of that same connector and the remaining tube or tubes are used for droppers fed from that bus wire.   Example... Wago connector example    

An alternative and much cheaper is to use cut up pieces of terminal block connectors and link across all one side of that block.  Usually terminal blocks are supplied in 12 way strips so you can have 2, 3 4 or whatever ways you want and by just link one side and using the other side for connections.  Or use a bare strip of copper wire and twist and solder droppers onto this small link (See image link)

Link to terminal block connectors  This give the  very basic idea... Link to example-1   Image link

 

You may find some useful information here too....  Link to my web site DCC section 

 

I have come across these Wago connectors although under a different name somewhere, the drawback I came up with was that the dropper wires would have to be quite longer if three are to meet up at one block, again correct me if I'm wrong. Similar to the terminal blocks mentioned that I've also seen in model shops and at shows, if I had it in the middle of the board the bus wire to it would be quite short rather than following a rough shadow of the loop, however the droppers would be longer to join in the middle (like a spiders web in my mind). I did buy some terminal blocks which joined together via pins, which I thought would be useful for keeping the boards able to be separated when needed (rarely, for decorating or other major work).

 

I think in the name of putting to use things I've paid for and developing skills, I'll have a go at soldering some of the droppers to the bus on the easier and more accessible areas. Not sure how that will go being underneath and everything being in a different place and angle to doing it on a desk with a helping hand so if it fails I'll likely go with the scotchloks, as with the harder to reach places.

 

One other thing that has come up while thinking earlier, I'll only be able to wire up one loop under DC, unless I did two completely separate bus wires, so that I can keep each loop under a separate controller. With DCC that won't matter, question was does one loop of bus wire carry enough to power both track loops and whatever is running on them? Or is my layout a long way smaller then the point of needing to think about that?

 

Thanks again

Link to post
Share on other sites
53 minutes ago, Tomathee said:

One other thing that has come up while thinking earlier, I'll only be able to wire up one loop under DC, unless I did two completely separate bus wires, so that I can keep each loop under a separate controller. With DCC that won't matter, question was does one loop of bus wire carry enough to power both track loops and whatever is running on them? Or is my layout a long way smaller then the point of needing to think about that?

 

There's nothing to stop you having two separate track buses so that both tracks can be controlled independently when using DC - since that is your start point.  The same two bus approach can be adopted under DCC as well with each loop being a separate power sub-district if you want.  If you set up a DCC Command station with a circuit breaker between the Command Station and each of your two track buses, then if you get a short on one loop, the other will remain operational.

 

However, your layout is relatively small (although you haven't said what gauge you are using), so I doubt that you need to worry too much about the current handling capacity of your bus wire.  Wire with a cross section of 1.5 mm2 will carry more current than your Command Station is likely to be able to supply (typically up to 6 Amp maximum) and voltage drop over the size of layout that you are building shouldn't be enough to cause any issues.

 

 

  • Thanks 1
Link to post
Share on other sites
8 hours ago, Tomathee said:

Thank you all very much for the replies, didn't expect so many.

 

 

I had a quick look at scotchloks (helpful to have the correct name now) and these seem quite cheap and easy to install, which is over-riding my previous apprehension. Do you have a link to a specific example please? Those I saw had a drop down for colour without indicating any other difference, if 'red' is to do with the size of the wire that will pass through etc. These Scotch Locks (ebay) are an example I came across, is it just wire cross section I should be interested in or are there other considerations such as maximum amp/volts (sorry, electricity is not my strong point).

 

 

...

 

Those ones are correct going from 0.5mm2 - 1.5mm2. (you do need to be careful on the colours and check spec as not all copies adhere to the ScotchlLok scheme :( )They are easy to use and 100% reliable. They are used in many critical situations. You just need to be careful that you use the correct size of wire from the particular ScotchLok. As for current and voltage, they can handle a lot more than exists in a DCC application :)

  • Thanks 1
Link to post
Share on other sites
11 hours ago, Tomathee said:

<Snip>

I have come across these Wago connectors although under a different name somewhere, the drawback I came up with was that the dropper wires would have to be quite longer if three are to meet up at one block, again correct me if I'm wrong. Similar to the terminal blocks mentioned that I've also seen in model shops and at shows, if I had it in the middle of the board the bus wire to it would be quite short rather than following a rough shadow of the loop, however the droppers would be longer to join in the middle (like a spiders web in my mind). I did buy some terminal blocks which joined together via pins, which I thought would be useful for keeping the boards able to be separated when needed (rarely, for decorating or other major work).

<Snip>

One other thing that has come up while thinking earlier, I'll only be able to wire up one loop under DC, unless I did two completely separate bus wires, so that I can keep each loop under a separate controller. With DCC that won't matter, question was does one loop of bus wire carry enough to power both track loops and whatever is running on them? Or is my layout a long way smaller then the point of needing to think about that?

 

Thanks again

Hi

The Wago 221 which I showed a link to an example can accept one or more dropper wires per tube even if 7/0.2mm wire is used. Whatever is sued you would normally use more than one (pair) for connections.

So long as your DCC bus pair of wires are of a suitable wire gauge size then normally only one DCC bus pair is used.  I would use 1.5mm2 solid or 32/0.2mm flexible as a minimum (similar wire sizes are also available) and for most home layouts these would be more than adequate.  Using a larger bus wire size won't hurt at all.  

If you have one loop as DC power and the other DCC then there most be no interconnection between the two loops. No cross-over points etc.  All wiring for each loop should ideally be in totally different insulation colours to avoid accidental cross connections.

Edited by Brian
  • Thanks 1
Link to post
Share on other sites
5 hours ago, WIMorrison said:

 

Those ones are correct going from 0.5mm2 - 1.5mm2. (you do need to be careful on the colours and check spec as not all copies adhere to the ScotchlLok scheme :( )They are easy to use and 100% reliable. They are used in many critical situations. You just need to be careful that you use the correct size of wire from the particular ScotchLok. As for current and voltage, they can handle a lot more than exists in a DCC application :)


Take care with the red ScotchLok on 7/0.2 it wire is only about 0.3mm2 so a little under spec. The problem with ScotchLok connectors is when you have quite different wire diameters they can almost cut through large wires beyond spec. But worse on thin wires outside the specs they may not completely displace the insulation. I would advise going up to 16/0.2. 
 

Although Wagos are more geared for mains wiring the lever type will definitely grip 7/0.2. They are the ones that I have used on house wiring but have tried them on 7/0.2 and they are a good connection that will not pull out.

 

Richard

  • Thanks 1
Link to post
Share on other sites

Note the red suitcase connectors are speced to 22AWG , which suits 16/0.2 wire , 7/0.2 wire has a cross section of 0.25mm2 and is considerably outside the scotchlok spec. ( the nearest AWG is 24 but this is actually wrong for 7/0.2 ) 

 

ive found such suitcase connectors when used on undersized wire to have poor reliability as the IDC mechanism doesn’t work well, with then becoming loose connections over time 

Edited by Junctionmad
  • Thanks 1
Link to post
Share on other sites
On 22/03/2020 at 22:18, sjp23480 said:

 

RAF96

This looks interesting, where do you get them from?
Steve

 

Brimal.co.uk as hinted at on the board.

just be aware to hold the in and out connectors as you tighten them as they are only secured by the soldered connections to the board. The top and bottom ones are OK. They seem to be handling my single garage sized layout loads OK. If the indicator load is a problem then just lift the resistor and install a bigger and better one. It shows red or green for DC polarity or orange for DCC present.

Edited by RAF96
Typos
  • Thanks 1
Link to post
Share on other sites

Thanks for the second lot of replies, I do check in more often on my phone but it's easier to reply when I can get to a desk.

 

Someone mentioned gauge, I'm using 00. I get the point about using wires of the same size, so I think I'll use the 1.5mm2 for the bus and the droppers where I'm going to use the scotchlok connectors, and use the 7/0.2 for any droppers that I solder to the bus.

 

Hopefully this will be the best plan to not waste the 7/0.2 and not need to buy any extra wire I don't already have.

 

Many thanks again for everyone's input and help

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.