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Tapping into existing wire runs

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Tapping into existing wire runs
Posted by Kurt_Laughlin on Friday, October 26, 2007 9:46 PM

In another thread someone wrote:

"I actually cut the buss wire and slip a piece of heat shrink tubing over one end, then do a western union splice to the buss wire.   I bring the ends of the drop leads to the splice, twist them over, then solder the whole thing. Then slide the heat shrink tubing over the joint, heat it to shrink, and the joint is done."

Is this the common way of making a soldered "T" connection?  I've always wondered how you got the insulation off the middle of a wire without nicking the conductor.  One issue I see with the method above is that you buss wires have to a good bit of slack to allow overlap for the splice.  It would seem that this would limit the number of connections you could make and require a bit too much planning.

KL

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Posted by mobilman44 on Friday, October 26, 2007 10:03 PM

Hi,

I was a "if it ain't soldered it ain't good" connection kind of guy - until I was introduced to all the newfangled stuff now available.  For connecting a wire to an existing run, there is a "suitcase connector", which fits over the run wire, and the connecting wire fits in along sid it.  Squeeze with pliers and fold the top of the connector over the unit (hence "suitcase" and its good to go.  I still check with a connectivity testor, but have yet to have a problem connection.  I actually did 4 of these about 2 hours ago.  

ENJOY,

Mobilman44

PS:  These are available at Lowes or Home Depot. 

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

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Posted by Vail and Southwestern RR on Friday, October 26, 2007 10:05 PM

There are wire strippers that grab the insulation from both sides and push/pull it apart.  Though I have not seen them in acton.

 

Jeff But it's a dry heat!

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Posted by larak on Friday, October 26, 2007 10:07 PM

You are right about the loss of length. I just use a stripper that pushes back the insulation, wrap the drop and solder. Cover with tape or Scotchkote.

You can also strip half an inch of the bus wire with a knife.

 

Karl

Edit: Those strippers work great Jeff. I've had two pairs in my electronics shop for many years.

The mind is like a parachute. It works better when it's open.  www.stremy.net

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Posted by Kurt_Laughlin on Friday, October 26, 2007 10:09 PM

Mob:

Sorry, I was really asking about soldered connections, as noted in my edited post above.  Not that I really want to do it that way, but I wondered how it was done.

KL

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Posted by LNEFAN on Friday, October 26, 2007 10:51 PM

I recently completed wiring my layout for DCC by dropping a feeder to the buss from every section of track. The feeders were then soldered to the main buss wires. In order to strip the buss wire to make the Tee connection I use Ideal Industries Stripmaster wire stripper. I bought it at Lowes for approx. $25.00 and it is worth every penny. This is a superb tool that made the work extremely easy. Highly recommended. Link to Stripmaster below:

http://www.idealindustries.com/products/tools_totes/wire_strippers/stripmaster.jsp

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Posted by Vail and Southwestern RR on Friday, October 26, 2007 11:36 PM
 larak wrote:

You are right about the loss of length. I just use a stripper that pushes back the insulation, wrap the drop and solder. Cover with tape or Scotchkote.

You can also strip half an inch of the bus wire with a knife.

 

Karl

Edit: Those strippers work great Jeff. I've had two pairs in my electronics shop for many years.

I figured they did.  I've just never had enough need to cause me to get a set!

 

Jeff But it's a dry heat!

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Posted by fkrall on Saturday, October 27, 2007 7:53 AM
I have a Stripmaster and second your comment--it's great. But I've always used it to strip the end of the wire.

I presume you're stripping within the run, which I've never done. I tested it with the Stripmaster in the proper hole and cut through the wire. What's your technique--using a larger hole to scrape down the insulation? That seemed tedious to me, but perhaps I simply need more patience!

Rick Krall
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Posted by LNEFAN on Saturday, October 27, 2007 8:20 AM
I simply place the wire in the proper size hole (in my case 14 ga) and squeeze the Stripmaster as usual. This will spread the insulation about 1/2" or so and expose the copper wire-ready for the soldered tee connection. If you place the wire in the hole improperly it could cut the wire. That's happened to me a few times in stripping wire ends (I was careless) but never on the main bus.
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Posted by Seamonster on Tuesday, October 30, 2007 11:08 AM

Sorry about replying so late but I haven't been on the forum for  a while.  I use the method you described, but like you said, it requires some slack in the buss.  As someone else mentioned you could cut into the insulation with wire strippers and pull back.  This will open a short length of bare wire.  I've done that too.  Another way is to cut into the insulation all the way around with either a knife or strippers, two cuts, about 3/8" apart, then with a sharp knife slice through the insulation between the cuts, blade parallel to the wire like you were peeling an orange, then pull off the piece of insulation.  Not easy, but doable.  I also subscribe to the "soldered is best" philosophy.Smile [:)]

..... Bob

Beam me up, Scotty, there's no intelligent life down here. (Captain Kirk)

I reject your reality and substitute my own. (Adam Savage)

Resistance is not futile--it is voltage divided by current.

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Posted by ChrisNH on Tuesday, October 30, 2007 11:51 AM

For insulating the soldered T-joints, I use a liquid insulation you can paint onto the joint. Its about $6 for a bottle at hardware stores.

Regards,


Chris

 

 

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Posted by ndbprr on Tuesday, October 30, 2007 4:18 PM
Theoretically it should be possible to use bare wire for the bus.  If they are kept apart say 12" and supported by individual screw eyes or the equivalent and all the wires attached to them are insulated.  I suppose it would be ok to have the bus be uninsulated.  Bus bars in high voltage switchgear are not insulated in some cases either.  Now if you want to run them right next to each other or through the same screw eye or where they attach to the DCC unit and are close forget the above.
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Posted by Vail and Southwestern RR on Wednesday, October 31, 2007 12:44 AM

 ndbprr wrote:
Theoretically it should be possible to use bare wire for the bus.  If they are kept apart say 12" and supported by individual screw eyes or the equivalent and all the wires attached to them are insulated.  I suppose it would be ok to have the bus be uninsulated.  Bus bars in high voltage switchgear are not insulated in some cases either.  Now if you want to run them right next to each other or through the same screw eye or where they attach to the DCC unit and are close forget the above.

When I first read this, I thought to myself, "What the heck is he thinking!".  But, then I thought some more..."What are the rails, if not an uninsulated bus topside?"  I might suggest a different method than screweyes, since you can't see where the point is, but it is a completely doable idea.  In fact, if you really have control of the feeders, they wouldn't have to be insulated either.

On the other hand, there can be lots of 'stuff' going on under the layout.  Do you always want to have to worry about the possibility of shorting your bus when you put anything through the surface, or shove something under the layout?  The rails we can see, and it is usually (not always) clear when we've caused a short.  It is much harder to see what's going on underneath.  And keeping track of which wire was which would be much harder without the colored insulation to tell you.  So, I think I would not do it, but it is an interesting thought, and much less ridiculous than it sounds at first.

 

Jeff But it's a dry heat!

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Posted by dstarr on Thursday, November 1, 2007 9:59 PM
 Kurt_Laughlin wrote:

In another thread someone wrote:

"I actually cut the buss wire and slip a piece of heat shrink tubing over one end, then do a western union splice to the buss wire.   I bring the ends of the drop leads to the splice, twist them over, then solder the whole thing. Then slide the heat shrink tubing over the joint, heat it to shrink, and the joint is done."

Is this the common way of making a soldered "T" connection?  I've always wondered how you got the insulation off the middle of a wire without nicking the conductor.  One issue I see with the method above is that you buss wires have to a good bit of slack to allow overlap for the splice.  It would seem that this would limit the number of connections you could make and require a bit too much planning.

KL

  No that ain't the way I would do it.  Cutting and splicing the bus wire is hard work and trouble prone.  No splice is going to be as sound as  the original wire.  I'd just strip a 3/8" of the bus wire and wrap the stripped end of the feeder wire around the stripped bus wire and then solder.  I don't bother to insulate the feeder wire Tee joint.  It's low voltage and safe to touch.  Stagger the north rail and south rail feeders so that they won't touch even if the bus wires are pressed together.  Secure the bus wire with staples or wire loom to the underside of the benchwork to prevent the bus wire from getting pressed together.  Use good stout bus wire that won't mind a small nick from wire stripping.  Number 14 solid copper house wire is good this way.

 

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Posted by spidge on Thursday, November 1, 2007 11:23 PM

I'm with you David Star. I used this very method minus the solder and haven't had a problem yet. I plan to solder, just haven't done it. I am not sure if I will leave it like it is or not.

I saw a thread somewhere that showed some screw on connectors to tie into existing runs without cutting. I think they were called sure locks or lock tites, something like that. I have been looking for them. The auto stores carry the brand but not the T tie in type connector. I liked them as you can add as many as four wire into the tie in part. 

John

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Posted by fkrall on Friday, November 2, 2007 5:54 AM
Great post, David Starr. "Stagger joints" and "#14" alone worth the price of admission for a beginner like I.

Rick Krall
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Posted by dstarr on Friday, November 2, 2007 10:11 PM
 spidge wrote:

I'm with you David Star. I used this very method minus the solder and haven't had a problem yet. I plan to solder, just haven't done it. I am not sure if I will leave it like it is or not.

I saw a thread somewhere that showed some screw on connectors to tie into existing runs without cutting. I think they were called sure locks or lock tites, something like that. I have been looking for them. The auto stores carry the brand but not the T tie in type connector. I liked them as you can add as many as four wire into the tie in part. 

   Things will work for a long time without solder.  But, given a few years and a little humidity in your train room, the bright shiny copper wire will tarnish.  In extreme cases, it goes all the way to that green color you see on copper roofs.  When the tarnish/corrosion gets bad enough the joint stops conducting electricity.  Whereas the same joint soldered will last forever, the copper-solder joint is gastight and won't tarnish.  BTW, the joint solders easier when the wire is bright and shiny.  

I 've seen some insulation displacement "suitcase" or "Tee" connector/splices.  Trouble is they are intended to join wires of the same size.  On the layout you want to join thin #22 or #24 feeders to a big fat #14 bus.  I've not seen a connector/splice that does that.  

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Posted by dstarr on Friday, November 2, 2007 10:20 PM

 fkrall wrote:
Great post, David Starr. "Stagger joints" and "#14" alone worth the price of admission for a beginner like I.

Rick Krall

Actually, #14 is overkill from an electrical standpoint.  But it is mechanically rugged, and since it's used to wire houses, it's easy to obtain.  If you happen to have, or can get for cheap,  #16 or even #18 is thick enough for bus wire.  Myself, I'd think #20 is too small.  

 

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Posted by spidge on Friday, November 2, 2007 11:54 PM
 dstarr wrote:
 spidge wrote:

I'm with you David Star. I used this very method minus the solder and haven't had a problem yet. I plan to solder, just haven't done it. I am not sure if I will leave it like it is or not.

I saw a thread somewhere that showed some screw on connectors to tie into existing runs without cutting. I think they were called sure locks or lock tites, something like that. I have been looking for them. The auto stores carry the brand but not the T tie in type connector. I liked them as you can add as many as four wire into the tie in part. 

   Things will work for a long time without solder.  But, given a few years and a little humidity in your train room, the bright shiny copper wire will tarnish.  In extreme cases, it goes all the way to that green color you see on copper roofs.  When the tarnish/corrosion gets bad enough the joint stops conducting electricity.  Whereas the same joint soldered will last forever, the copper-solder joint is gastight and won't tarnish.  BTW, the joint solders easier when the wire is bright and shiny.  

I 've seen some insulation displacement "suitcase" or "Tee" connector/splices.  Trouble is they are intended to join wires of the same size.  On the layout you want to join thin #22 or #24 feeders to a big fat #14 bus.  I've not seen a connector/splice that does that.  

I agree that I should solder soon as its been about two years since I wired it up.

I will look up the manufacturer of the splicers I am suggesting and post it. It actually ties into a specific size wire and allows multiple feeder through the top, such as a #14 bus with 4 #20 feeders. This uses the same priciple as the suitcase connectors but is different.

John

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Posted by Vail and Southwestern RR on Saturday, November 3, 2007 4:03 AM
 dstarr wrote:

 I 've seen some insulation displacement "suitcase" or "Tee" connector/splices.  Trouble is they are intended to join wires of the same size.  On the layout you want to join thin #22 or #24 feeders to a big fat #14 bus.  I've not seen a connector/splice that does that.  

Here is one, #22 tap, #14 run:

http://products3.3m.com/catalog/us/en001/utilities_telecom/electrical_contractors/node_GSLQW8MSW6be/root_GST1T4S9TCgv/vroot_GSBCDFDZ1Zge/gvel_RZZJLFZNT6gl/theme_us_electricalcontractors_3_0/command_AbcPageHandler/output_htm

l

You can get them here:

http://www.mouser.com/search/refine.aspx?Ntt=scotchlok+905

 

Jeff But it's a dry heat!

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Posted by Vail and Southwestern RR on Saturday, November 3, 2007 4:06 AM
 dstarr wrote:

Actually, #14 is overkill from an electrical standpoint.  But it is mechanically rugged, and since it's used to wire houses, it's easy to obtain.  If you happen to have, or can get for cheap,  #16 or even #18 is thick enough for bus wire.  Myself, I'd think #20 is too small.  

Depending on the layout the numbers don't support this statement.  There are lots of factors that can lead to never having a problem with wire smaller than #14, but if you have any runs of longer than 20 feet or so, and will be running consists of locomotives, using smaller is asking for trouble when you least expect it.  On a lot of smaller layouts #16 would work, I don't think I would ever use #18.

 

Jeff But it's a dry heat!

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Posted by dstarr on Monday, November 5, 2007 8:44 PM
 Vail and Southwestern RR wrote:
 dstarr wrote:

 I 've seen some insulation displacement "suitcase" or "Tee" connector/splices.  Trouble is they are intended to join wires of the same size.  On the layout you want to join thin #22 or #24 feeders to a big fat #14 bus.  I've not seen a connector/splice that does that.  

Here is one, #22 tap, #14 run:

http://products3.3m.com/catalog/us/en001/utilities_telecom/electrical_contractors/node_GSLQW8MSW6be/root_GST1T4S9TCgv/vroot_GSBCDFDZ1Zge/gvel_RZZJLFZNT6gl/theme_us_electricalcontractors_3_0/command_AbcPageHandler/output_htm

l

Not bad.  That's a new on on me.

 

 

You can get them here:

http://www.mouser.com/search/refine.aspx?Ntt=scotchlok+905

 

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Posted by fwright on Tuesday, November 6, 2007 1:52 PM

 ndbprr wrote:
Theoretically it should be possible to use bare wire for the bus.  If they are kept apart say 12" and supported by individual screw eyes or the equivalent and all the wires attached to them are insulated.  I suppose it would be ok to have the bus be uninsulated.  Bus bars in high voltage switchgear are not insulated in some cases either.  Now if you want to run them right next to each other or through the same screw eye or where they attach to the DCC unit and are close forget the above.

This has been my practice for all my common rail DC layouts (and 3 rail O AC layouts).  I ran some Radio Shark bare antenna wire (braided 16 gauge) in a loop near the perimeter of the layout.  Dropped feeders - on the DC layouts I used 24 gauge magnet wire - and used a few swipes of crocus cloth on both the magnet wire and the antenna wire to prepare them.  I then wrapped the magnet wire around the bus a couple of times and soldered.  The magnet wire was nice because it was so thin - an 1/8" hole was plenty big, and it was near invisible next to the the track.

I only had a single bus on these layouts so keeping track of a single common rail and bus was not difficult.  With most track plans and 2 bus, keeping rail and bus matched should not be difficult, either.  Reversing loops have to wired separately so they don't add to the complexity.  Bowl-of-sphagetti plans and figure 8s would be the most problematic. 

my thoughts, your choices

Fred W

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