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Terminal strips

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  • Member since
    January 2012
  • From: Edgewood, WA
  • 54 posts
Terminal strips
Posted by 2ManyHobbeez on Saturday, February 13, 2021 3:25 PM

Anybody know of a source for clamp type terminal strips that will work for small (like 28 AWG) stranded wire? I got some of the "Eurostyle" strips recently but they are basically junk for small wires as they screw down on the wire and the screw doesn't even reach the bottom of the receptacle.

George

Edgewood, WA

  • Member since
    September 2003
  • 21,669 posts
Posted by Overmod on Saturday, February 13, 2021 3:47 PM

The 'traditional' answer to this is to use a washer, or a small strip of hammered-out solder, between the screw and the wire, to make a 'crushable' contact to the fine wire without deforming or stressing it.

An alternative is to tin the thin wire end repetitively with heavy fluxing to build up the 'contact' end thickness with solder to accomplish the same end.  You could pre-form a loop or bend in the wire before tinning if you want.

NB that the kind of 'clamp' with a lateral screw torqued sideways against the wire also cuts or stretches wire (and requires a former, plate, etc. between the nose of the screw and the actual wire whether it is stranded or solid)

  • Member since
    December 2015
  • From: Shenandoah Valley
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Posted by BigDaddy on Saturday, February 13, 2021 4:18 PM

Or you could use the barrier strips that have screws and captures the wire.

Is this for lighting or signals?

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 18,255 posts
Posted by SeeYou190 on Saturday, February 13, 2021 4:59 PM

2ManyHobbeez
Anybody know of a source for clamp type terminal strips that will work for small (like 28 AWG) stranded wire?

Are you referring to the type where the wire is inserted into a hole and then a cam lever flipped to make secure contact?

If so, no. I have only seen these work with wire size down to 18 gauge.

-Kevin

Living the dream.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Saturday, February 13, 2021 5:12 PM

For wires under 26 gauge I solder them to header strips and make them plug ins.

I buy single row and double row header strips and cut them to length.

To insure the right connection I polarize them.



I buy the header strips off eBay in quantity, they come in 40 pin single row and 80 pin double row both male and female.

They work great for signals and such.



Those connectors are dual row two pin, four connects, with one pin reversed for polarization to insure the four wires can’t be reversed.

I also use them in my locomotives for the decoder wiring.

This is an extension between the internal wiring and the connector to the tender.

They work great for wiring up structure lighting too, I use Arduino random lighting controllers for my structures.  The Arduino has 20 switched out puts so a 11 pin double row connector works out nicely and they are very small.  The price is right too, about 2¢ per pin.

 

Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    September 2003
  • 21,669 posts
Posted by Overmod on Saturday, February 13, 2021 6:11 PM

SeeYou190
Are you referring to the type where the wire is inserted into a hole and then a cam lever flipped to make secure contact? If so, no. I have only seen these work with wire size down to 18 gauge.

They work beautifully down to #36... by inserting a short piece of stripped, say 18-gauge stranded in the hole along with the fine wire.  I played around with separating strands and then retwisting with one strand replaced by fine (tinned) wire to get the thin strand away from the periphery and assure more 'copper' surface area to contact.  You can of course tin the stranded wire and solder the tinned fine-gauge wire to it ... then clamp the result.

Other ways to incorporate strain reliefs, create smooth transitions from fine to larger wire, etc. will quickly suggest themselves -- the idea being to have the necessary copper cross-section for the clamp to engage mechanically, just in the length it needs to do so.

A key detail (for me at least) in securing fine wire by tightening a screw is avoiding torque or drag by the turning screw head on the wire.  That is part of what a 'washer' or interposed shim does; it keeps any 'twisting' from combining with clamping force.   One good type of terminal puts the actual screw head on the opposite side of the terminal frame, with the equivalent of a flat nut on the other side; the wire is compressed between this nut and the metal contact seat in the strip, and of course has little if any torque even at colossal tightening pressure.  Other designs (I see them in replacement plugs and some 120V electrical fittings) use a roughly square-U-shaped washer that straddles the metal terminal block, with the wire being stripped to a gauge and then inserted straight into the gap between the U and the block, either side of the screw thread.  Here again very great clamping force can be 'tightened down' without pulling or fretting the wire, and multiple conductors can be inserted with easy field prep and minimum wire waste without having to resort to ring terminals, etc.  

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Saturday, February 13, 2021 6:26 PM

2ManyHobbeez
Anybody know of a source for clamp type terminal strips that will work for small (like 28 AWG) stranded wire?

I bought several of these for use where I'm mounting signals or street lights. They work great with the finer wire sizes.

 

Terminal Block

 

I agree that those screw-type terminal strips are not suitable for fine wire. Some have a "pressure pad" in there but this still isn't much of an improvement.

 IMG_4860 by Edmund, on Flickr

Good Luck, Ed

  • Member since
    January 2012
  • From: Edgewood, WA
  • 54 posts
Posted by 2ManyHobbeez on Sunday, February 14, 2021 1:34 PM

Thanks for all the advice guys. Ed's pictures show the issue. I bought strips similar to the white ones on the bottom. They do not have a wire protector but the blue ones do. I snooped around a lot yesterday and found Altech HE1WPR strips which are advertised to work down to 24awg. I'll see if I can cheat on that a bit. The good thing is that supplementary parts are available for this product in particular shorting strips.

I am building out a system that uses Arduino Nanos connected by a CAN bus that will combine block detection, turnout control and status and signals. There will be a lot of wires.

George

  • Member since
    December 2001
  • 1,190 posts
Posted by mvlandsw on Sunday, February 14, 2021 3:48 PM

Are there any terminal strips that will connect one input wire to multiple output wires without having to gang a bunch of terminals together as on a barrier strip?

Mark

  • Member since
    January 2012
  • From: Edgewood, WA
  • 54 posts
Posted by 2ManyHobbeez on Sunday, February 14, 2021 5:14 PM

mvlandsw

Are there any terminal strips that will connect one input wire to multiple output wires without having to gang a bunch of terminals together as on a barrier strip?

Mark

 

See gmpullman's last post...

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Sunday, February 14, 2021 7:07 PM

2ManyHobbeez
See gmpullman's last post...

     — even more choices:

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=power+distribution+board&_sacat=0

Maybe the link in my previous reply doesn't work for some browsers.

Good Luck, Ed

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Monday, February 15, 2021 7:46 AM

jumpers ?

greg - Philadelphia & Reading / Reading

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