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?
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
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
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.
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:
You can just secure the stripped wire end under the screw. Create a curve and fit the wire under the screwhead so the end of the wire is clockwise. That way when you tighten the screw it will draw the wire in under the head. Fine wire can be wrapped completely around the screw before you tighten it down.
I use spade terminals myself to facilitate removal and reconnection but if isn’t necessary. If you wish to secure more than one wire under the same screwhead then inserting both wires into one spade connector works more reliably than fitting two wires under one screw but it isn’t necessary. Twisting the wires first works. Tanning both wires together works well also.
Tinning the bare wire first can help secure the wire under the screwhead. The solder distorts as you tighten the screw down which increases grip.
If you fit a spade terminal it’s important to use the correct one for the wire gauge. That also needs to have a correct size spade to fit around the screw. Often this isn’t achievable in which case a wire wrap around the screw will be your only option.
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?
Atlas supplies spade connectors suitable for their switches. These are too small for many terminal strips. Most spade connectors are too wide for Atlas terminals.
You don’t need special crimpers for this task. The usual combination stripper/crimper tool is sufficient if you use care in crimping in the right spot.
The issue with soldering or tinning stranded wire ends is it creates a hard spot but then so does crimping. Relying on spikes in the crimp on connectors makes for a less reliable connection than stripping but can have the advantage for fine gauge wire of transferring the gripping force to the insulation. Ideally the fitting will be designed so that spike grips the insulation but the electrical contact is bare wire.
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” !
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.
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!
For turnout control you won’t need three wires all the way from the switch to each turnout motor. You can string the power wire as a single bus wire if convenient. For Atlas that’s the black wire and for Peco it’s the green wire.
So you only need two wire connectors for the red and green wires all the way from the switch to each turnout motor.
For small gauge wire connection strips look at these instead of those screw type:
I just bought a few Wago connectors to try. They look super easy to use.
I also bought a few of these:
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
This has been my experience also.
My best results with 22 gauge wire and thinner have been achieved using no terminals and tinning the end of the bare strands to thicken up the total contact area. The solder is softer than copper wire and any sort of compression connector tends to grip solder better than bare copper wire. I find a crimped fitting grips much better if crimped onto still warm tinned wire.
For crimped connectors I find that stripping only the minimum bare end needed for good electrical contact works best. Then try to crimp down close to the end of the insulation so part of the crimp grips the insulation a little. There is a metal tab stop inside standard crimp fittings which indicates where the bare end of the wire should reach to. Strip only what you need to in order to crimp down on bare wire just short of that stop.
You’re trying to avoid creating a bending point where the insulation ends and the bare wire begins. Standard crimp fittings have a rigid plastic cover that moves the bending point back away from the beginning of the strip point.
Atlas spade connectors designed to exactly fit their switch system are not easy to crimp and do not have insulating covers. I have experienced multiple failures of Atlas space connections right where the connecting wire gets bent right at the tubular crimp point even though we solder ours and do not try to crimp the spade connector. We try not to allow any bend in the wire right at that point, leaving a curve or loop between that joint and the rest of the wire run. That seems to work. Wire quality also mak
Excellent, thorough response Overmod! Thanks! Replies like yours are why I come to the forum! [Y]
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