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Best method to secure fine wire to terminal strips

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Best method to secure fine wire to terminal strips
Posted by IDRick on Friday, December 3, 2021 12:52 PM

I'd like to use terminal strips in a control panel.  I am considering this particular terminal strip and will be connecting 18 awg and 24 to 26 awg feeders (all are stranded).  Is it necessary to use a crimped or soldered spade connector for the 24 to 26 awg wire or can it be doubled up and provide sufficient reliable contact?

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Posted by doctorwayne on Friday, December 3, 2021 1:40 PM

As best as I can recall, I don't use terminal strips for anything on my layout.  If I'm using fairly fine wire for a toggle switch, I usually strip the insulation off the end, then apply solder to the twisted-together strands of the wire. 

Wayne

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Posted by ndbprr on Friday, December 3, 2021 2:46 PM

They do make crimp on lugs that are just a straight tube you crimp on the wire that you c an tighten under the screw

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Posted by jjdamnit on Friday, December 3, 2021 3:32 PM

Hello All,

I use either crimp-on spade connectors or tin the ends of the stranded wire with my terminal strips.

You can use two (2) spade connectors on the same lug of the terminal strip. Just put the two spade connectors "back-to-back" or flat-to-flat.

Spade connectors come in sizes ranging from 22-16 AWG (red), 16-14 AWG (blue), and 12-10 AWG (yellow).

The 22-16 AWG (red) connectors will work with the smaller gauge wires you listed. A good crimping tool will ensure a good connection.

I use the Klein Crimping tool. Although the tool is intended for non-insulated connectors, I use it with insulated connectors with great results.

Yes, you can crimp two (2) 24 and/or 26 AWG wires in a 16-14 AWG connector with reliable contact. 

One thing to consider is if you do crimp two (2) wires in the same connector it makes troubleshooting more difficult.

If you don't want to use spade connectors the next best option, as I said, is tinning the ends of the stranded wire.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by York1 on Friday, December 3, 2021 4:49 PM

IDRick
I'd like to use terminal strips in a control panel.  I am considering this particular terminal strip and will be connecting 18 awg and 24 to 26 awg feeders (all are stranded).  Is it necessary to use a crimped or soldered spade connector for the 24 to 26 awg wire or can it be doubled up and provide sufficient reliable contact

 

I use the same terminal strips.  I didn't buy a crimping took, but my wire stripper has a crimping hole which works fine.  I use spades.

I really think the spades are unnecessary.  I think the stripped wire, inserted into the terminal block, would provide the needed connection once the screw is tightened.

I don't see any problem with doubling up the wires.  As long as the connection is tight, it's probably no different than your house wiring, with twist-on wire connectors to splice two wires.

I guess the advantage of using the spades is that it is a "cleaner" connection and allows easy connecting/disconnecting:

 

York1 John       

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Posted by IDRick on Saturday, December 4, 2021 1:07 AM

Thanks guys!  Good information, you helped me to do things correctly!  I'm using the terminal strips to organize power buss drops in a control panel.  Theoretically, wires are only installed once so a spade connector is probably not necessary but may make for an easier, quick, and neater installation.  I am using the power buss with Ken Stapleton's 751d turnout switch.  Based on Kevin's directions, I need to go with larger wire (24 or 22 AWG) for the drop.  Kevin's suggested spade connectors would fit well with a move up to 22 AWG from my planned 26 AWG wire.  Kevin tell me more about the required crimper.  My wire stripper has a crimper, is that adequate or do I potentially need to purchase a special crimper?  Can you tell me the size of the spades?  What is the inside width between spades and the outside width between spades?  Thanks!

There were some comments on soldering the wire end before inserting it into the terminal strip.  Forgive me for saying this but Randy Rinker was my go-to guy for many MR things and I pretty much have followed his advice.  In a post to these MR forums, Randy recommended NOT soldering or tinning stranded wire before wire to an atlas turnout machine (similar inserting into terminal strip).  I don't recall his reasoning.  Bottom line, is this a hard fast rule or a Randy recommended practice only?

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Posted by mobilman44 on Saturday, December 4, 2021 8:54 AM

From my experience, using solid wire feeders is significantly easier to deal with vs. stranded wire.  Be it stripping, soldering to wire/terminal connections and especially to the rails themselves, solid wires are the way to go - for me for sure.

Not knocking stranded wire, for that is the way to go for buss wiring as they are less susceptible to breakage and definitely more flexible.

Can't leave this post w/o adding........  No Model Railroader - on their death bed - was ever known to say......"I regret putting in all those extra feeders" !

 

ENJOY  !

 

Mobilman44

 

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

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Posted by Overmod on Saturday, December 4, 2021 9:35 AM

In my opinion the chief issue with fine wire in terminal strips is strain relief, not contact.

What i advise if you use a crimp terminal is to put a piece of shrink tubing over the thin wires before the end is crimped on.  Then slide it back down over the shank of the connector and shrink it.

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Posted by IDRick on Saturday, December 4, 2021 1:14 PM

Thanks guys, appreciate the discussion!

Update, I have come up with a different solution, Wago 221 connectors!  I have a couple on hand and found that the wago will tightly hold 22, 20, and 18 AWG stranded wire.  Thus, I can use 18 AWG for the buss and 22 AWG for the drops to the Stapleton 751d harness.

The harness has 24 AWG solid wire and Ken suggests using telephone cable to provide extra length as needed.  I have two lots of telephone cable on hand and both were 26 AWG stranded. They are easy to strip with my Klein 1157 and, after twisting, form a nice tight wire to easily attach to the atlas switch machine.

 

YES, YES, I agree, solid wire for track feeders is a must!

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Posted by Overmod on Sunday, December 5, 2021 7:58 AM

Either Kalmbach or crApple elves have destroyed the ability to selectively quote text using a phone, while retaining the difficulty of selecting and removing blocks of text from a long post in the window.  

The issue with tinning thin stranded wire isn't with the tinned portion, it's with stress raising at the point between tinned and untinned sections (and is complicated if excessive heat was applied to the untinned transition area during the tinning, or excess flux is left between untinned strands).  In fine wire these effects make for increased breakage.  If the wire is tinned close to the insulation, the problem might not be clearly visible and the first sign is pesky wires coming loose with little provocation.

As a general rule, I tinned wire ends going into clamp or push-type terminals (of the kind once common on small stereo speakers), but I left an untinned area visible and carefully washed the end.  If I were doing that today, I'd use a short piece of heat-shrink form about ½" up the insulation down to at least part of the tinned end as a strain relief.

I just have never liked the principle of connectors that pierce insulation, like suitcase connectors, no matter how full of clever insulating gel or whatever you make them.  They do fine for convenient automobile wiring... where relatively heavy AWG is used; I suppose for most relatively low model-railroad voltages they serve  OK, but when you get to small wires like 26ga I like the idea less.  I think it might be sensible to do some careful comparative testing of wire-piercing or insulation-displacing connectors and terminals to see if they actually work long-term in hobby use.

As I recall, in the crimping of 'modular' connector plugs the wire itself is displaced, down into the slot with the relevant terminal.  This is a bit like punchdown blocks at right angles.

Keep in mind that there is no real sin in using one kind of wire in a harness and then splicing a couple of inches of 'more compatible' wire at the business end where it gets a terminal fitting or needs to wrap around a screw.  The inline splice is relatively strong, won't be routinely bent, and can be easily insulated and strain-relieved.

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Posted by IDRick on Sunday, December 5, 2021 11:18 AM

Excellent, thorough response Overmod!  Thanks!  Replies like yours are why I come to the forum! Yes

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Posted by Steven Otte on Wednesday, December 8, 2021 9:15 AM

This thread has been cleaned up to remove the detritus of a nasty, personal insult. Attempts to continue to litigate that fight or the admin action taken in response will not be allowed.

--
Steven Otte, Model Railroader senior associate editor
sotte@kalmbach.com

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