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Soldering track feeds to bus wire


philsandy

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I am just beginning wiring my layout.

I have soldered solid copper wire droppers to every piece of track and then soldered flexible 1.5mm wire to these to run to the bus wires along the underside edge of the board.

It is only a small layout, "L" shape 8' x 6' and most of the track feeds are in a confined area of the station layout.

 

Is it OK to join all the wires from each feed together and then solder them to the bus wire as one wire so to speak. ie. join 10 red feed wires together and join the 10 black feed wires together and then solder each one to the corresponding bus wire.

Or is it better to connect them to the bus wires as individual connections.

 

I'm not very good at soldering and looking for an easier way round. I thought about using terminal blocks but am told they are not as reliable as a soldered joint.

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You have to remember that sections of your 1.5mm wire wil be carrying current to more than one piece of track if you do as you suggest. For your size of layout it should be fine.

 

It is true that soldering is more reliable, but there's nothing wrong with terminal blocks. Every house in the country has hundreds of screw connections in the mains wiring. For better reliability the wire ends should have a crimped-on ferrule before inserting into the screw terminal. What you should not do is tin the ends of the wire to solder the strands together when using terminal blocks.

 

Andrew

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On a practical note you might need to think about the size / power of your soldering iron.  I use the copper cores from 240 volt 'mains' cable for my 'buses'.  I only have a soldering iron with a 'fine' tip which is great for control panel work but it does not really have enough heat in it when attempting to connect 'droppers' to a big copper heat sink like my 'mains' bus.  It will work - but only just.

 

Just some rambling thoughts.

 

Ray

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I use terminal blocks for my layout which is 30ftx9ft, and with a dropper wire on every piece of track I reckon I have more than 600 dropper wires.  With this many it's always possible to have a loose wire on the block if you're not careful, but in my experience this is far rarer than a poor soldered connection, especially if you're not good at it (like me) and trying to solder underneath the baseboard.  So I use terminal blocks connected to the main bus via scotchlok connectors like this, and now having checked every terminal block I have no problems at all.

 

IMG_6920.jpg

 

Rather than using the plastic blocks shown and linking them up with wires you could use earth blocks from B&Q or Screwfix, like these which come in 4-way and 8-way versions:

 

http://www.screwfix.com/p/4-way-earth-blocks/12386:

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Always liked your scotchlok/terminal block idea, RFS, as I'm not the best of solderers, particularly when doubled-up under a baseboard! I don't think you've mentioned using the Earth Blocks before... and I've never come across them (like many things electrical!) How exactly do they work?

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I didn't know about earth blocks until I saw someone else mention them - and of course after I'd wired up my current layout.  Basically they're solid metal so you connect one thick wire to it from the bus, and then connect all the dropper wires in the area to the other sockets.  The block will of course be live, but so long as they're carefully positioned there shouldn't be any problem. You need separate blocks for each of the two bus wires

 

They're more expensive than the plastic terminal blocks so if you need a lot then cost could be an issue.  I used twin-and-earth wire for my bus so had plenty of good, solid copper wire spare (the earth wire) for joining the connections up on one side. I've found it's not a problem getting up to 3 dropper wires in each socket. 12-way plastic blocks cost about 40p each from the likes of Wilkinson's Hardware stores, or in packs of 10 from Ebay. 

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Thanks for that RFS. I was thinking they'd be live... and you've confirmed they are! Bit more fiddley with the plastic blocks, but I think I'll stick with them... having got plenty from Wilkinsons already (I use 'em to make my manual turnout units, but that's another story!)

 

Cheers

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I always tin wires which are to be placed in a terminal block.....no problems so far.

 

Curious to know why I shouldn't!

 

Solder is subject to "cold flow" under presure which can cause the terminals to become loose. Google '"cold flow" solder'

 

Andrew

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The block will of course be live, but so long as they're carefully positioned there shouldn't be any problem.

 

 

I was thinking they'd be live...

 

Use Choc-bloc covers to protect them.

Some earth blocks are available with the option of matching covers.

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Solder is subject to "cold flow" under presure which can cause the terminals to become loose. Google '"cold flow" solder'

 

Andrew

Surely this will only be a problem if you over do the solder?

If they are tinned so the strands are still visible there shouldn't be a problem especially if the screw pressure is enough to spread the wire.

I have seen plenty of commercially terminated wires with tinned ends.

 

Keith

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Solder is subject to "cold flow" under presure which can cause the terminals to become loose. Google '"cold flow" solder'

 

Andrew

The flip side being tinning the ends of stranded copper wire helps prevent individual strands from bending and breaking away when the wire end is clamped in a terminal strip.

 

The way to get round both of these is to crimp bootlace ferrules onto the wires before fitting to the terminal block.

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I've connected all my rail droppers to 2 common terminals. I've got one rail connected blue and another one connected yellow. All was well until I'd accidentally connected a left rail colour to a right rail and all connections were crimped. I had to destroy all the crimped connections to find the wire that I had incorrectly soldered to the rail. I'll never cluster individual droppers again!

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I have been trying a slightly different approach as I plan an extension to my layout.  On the first part (now almost complete) I found that I had rather long droppers (600mm or more) as some of my track is some distance from the power bus.  Taking a lead from someone who said he soldered two sets of droppers to each piece of track (in case one should fail) I decided to follow suit, putting each pair of droppers about 50mm from each end of each piece of rail.  I am connecting each each pair of droppers to those on the next section of track in the manner of a daisy chain; the last set of droppers in the line being attached to the power bus.  In effect i am using the droppers just as a bypass to the rail joiners.  Apart from soldering the droppers to the rails, all connections are by terminal blocks.  By this method I have been able to restrict the length of the droppers to 150mm maximum and use much shorter lengths of power bus.  I haven't doubled up the droppers on the points (there seemed to be enough wires already on them!) so I have to ensure they are connected in somewhere. 

 

If anyone feels this is a bad idea, please say so.  Probably no benefit for a simple track-plan but I think it has advantages for mine.  The extension will add 75 feet of flexitrack plus nine points and I have relayed 12 points and about 40 feet of track.

 

Harold.

 

Harold.

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Coc blocks a life saver.........

 

After re-laying my track I discovered a short which showed up after about 2 weeks of having completed the re-wiring via droppers to bus wires (1.5mm mains wire with .75mm droppers) I then had the task of tracing the short, no ballasting has been started yet so no collateral damage in that area.

 

In an attempt to isolate which section of track the short came from I decided to disconnect all droppers and re-connect the track to the bus wire piece by piece but only after I had replaced all the metal rail joiners with plastic ones on the basis that the only electrical connection is via the droppers to the bus wire so showing up any problems as I progressed around the layout, obviously rather than the metal rail joiners continuing to carry current in spite of the dis-connected droppers, so far this is working well with about a third of the layout wiring re-connected in this fashion.

 

This included all points on cross overs which are Peco insulfrog (fitted with droppers on the toes) and these are now fitted with plastic rail joiners on all connections and so far seem to be working fine, all droppers are connected to the bus wire with choc blocks which to me are a God send, given the sizes of wire I was told to use I have had to source a number of different sized choc blocks to allow for connections of droppers from double tracks e.g. 5amp, 15 amp etc.

 

The other advice I got on starting to wire the layout was to make sure to use stranded or flex wire rather than solid core, nothing was said about tinning the dropper ends before connection into the choc blocks,

 

I do not yet have the layout divided into electrical sections but will do so when I have proven that all electrical connections are ok and trsted repreatedly.Any thoughts on the universal use of plastic fish plates and electrical continuity via drop wires only?

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Coc blocks a life saver.........

 

After re-laying my track I discovered a short which showed up after about 2 weeks of having completed the re-wiring via droppers to bus wires (1.5mm mains wire with .75mm droppers) I then had the task of tracing the short, no ballasting has been started yet so no collateral damage in that area.

 

In an attempt to isolate which section of track the short came from I decided to disconnect all droppers and re-connect the track to the bus wire piece by piece but only after I had replaced all the metal rail joiners with plastic ones on the basis that the only electrical connection is via the droppers to the bus wire so showing up any problems as I progressed around the layout, obviously rather than the metal rail joiners continuing to carry current in spite of the dis-connected droppers, so far this is working well with about a third of the layout wiring re-connected in this fashion.

 

There is a way around this, so you don't accidentally create a short & keep going adding more wires and so making the short ever harder to find!

 

:scratchhead:

 

When you start the bus, connect the multimeter across the 2 legs of the bus & set it to continuity. Then as you install the wiring (do a touch where its going first), if you create a short the multimeter will start beeping continuously and you'll know instantly that you've got a problem, to investigate straight away & not way down the track (sorry for the pun).

 

If using the multimeter, check it doesn't turn itself off after a short while (battery saving) or you'll be in a worse position. Best thing is to short it out deliberately every couple of minutes.

 

Alternatively use a buzzer & battery.

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You shouldn't need to use IRJs as your only connector: they're not very strong and can easily cause kinks in curved tracks

 

Colour-coded wire should be all you need. My bus wires are from twin-and-earth so they're brown (outer) and blue (inner) and I use 1/0.6 for droppers of the same colour so there's no confusion. When I'm connecting up I do stop every so often and switch on the booster to make sure it doesn't short.

 

The only issue I have sometimes is when wiring up frog polarity switches, which can lead to a short when wired incorrectly, but at least I know where to look!

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Drops from the rail - solid 1mm2 stripped from normal Twin&Earth mains cable down through the baseboard.

Links to the power bus - flexible 0.5mm2, get a reel of blue and a reel of brown (or red and black if that is your preference). I solder the dropper to the thin wire and the thin wire to the power bus.

How about drawing the track plan on the underside of your baseboard so you can see which is the + rail and which is the - rail?

I personally am happy to solder everything, having a 25W iron that is good enough for almost all such applications and a 50W iron if all else fails.

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Dropper from rail: 16/0.2 red and black to 15A choc block just below track

Twisted red/black 1.5mm pair (taken from old mains lighting cable) to bus which is old (red/black) 2.5mm mains, in 30A choc block.

 

Terminal blocks are good quality from electrical suppliers, not market stall Chinese cr*p.

 

Keith

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I really find this all amazing, with DC I have probably three or four lengths of Streamline fastened together with fishplates with just one pair of 'droppers' to attach to the common return and the section switches. How difficult is that?  Talk about making work.

 

Regards

 

Ray

 

http://longsheds.blogspot.co.uk/

 

http://www.youtube.com/my_videos

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I really find this all amazing, with DC I have probably three or four lengths of Streamline fastened together with fishplates with just one pair of 'droppers' to attach to the common return and the section switches. How difficult is that?  Talk about making work.

 

Regards

 

Ray

 

http://longsheds.blogspot.co.uk/

 

http://www.youtube.com/my_videos

You are lucky. Many of us have resorted to regular droppers due to the crappy contact when just using fishplates (DC in my case)

So I now solder to the rails (all rails!)

 

Keith

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You are lucky. Many of us have resorted to regular droppers due to the crappy contact when just using fishplates (DC in my case)

So I now solder to the rails (all rails!)

 

Keith

Keith

 

Sorry to hear that you have not been so lucky.  I have been playing with model trains now for over thirty years and have always used the same approach to applying power to the track.  There are lots of scanned images on Flickr of previous layouts and the links above on my previous Post will take you to my present layout and some YouTube videos.  I even reuse rail joiners - I know because some of them are painted from my1980 layout.  However I do check them with pliers before reuse to ensure that they are still a very tight fit. I used wall paper paste to bind the track ballast together (poppy seeds) so the rails and joiners were not flooded with potentially corrosive fluid.  May be not just luck?

 

Regards

 

Ray

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