[advice] Crimp butt connectors for thin wire (~ 0.6 mm dia) - Page 1
Forum section: electronics / projects

author: onesixright
author_rank: Frequent Contributor
timestamp: March 14, 2020, 03:12:44 pm
content: Hi All,I need to connect some "magnetic detectors" (alarm door/window connectors). Its stranded wire, ~ 0.6 mm. Pretty thin.I was thinking of using "insulated butt crimp" connectors. Since the wires are pretty thin, anybettersolutions?Thanks!Rog.

author: hexreader
author_rank: Frequent Contributor
timestamp: March 14, 2020, 03:15:58 pm
content: Solder and heat-shrink - possibly two layers of heat-shrink if you want a stiff joinStagger the joints if there is more than one wire within outer heat-shrink

author: MarkL
author_rank: Unknown
timestamp: March 19, 2020, 02:42:14 pm
content: Quote from: onesixright on March 14, 2020, 03:12:44 pmIf you mean you were thinking of 3M Scotchlok UR and UY series butt connectors, those are the ones that telephone installers use. They are great for any environment and I would use them. They are not rated for stranded, but I've never had an issue using them on stranded.You can find the 3M ones and tons of look-alikes on Amazon. Search for "idc connector ur uy":https://www.amazon.com/s?k=idc+connector+ur+uyEDIT: Fixed up url.

author: onesixright
author_rank: Frequent Contributor
timestamp: March 19, 2020, 03:08:35 pm
content: Thanks both!Problem is with soldering: its around the house, and soldering on a ladder doesn't seem like a great plan. The magnets are already installed and wire length is only ~ 30 cm. SI was thinking of the crimping ones used in automotive industry. The wire/connector will be place above the door/window frame. This will be closed later with plaster. I will make a photo this weekend, since its a bit hard to explain.Again, thanks so far.

author: Gregg
author_rank: Super Contributor
timestamp: March 19, 2020, 05:33:31 pm
content: Dolphin connectorshttps://www.amazon.com/Dolphin-DC-100S-Super-Connector-Sealant/dp/B000JP3GB6are typically used for these type of installations. They are available with moisture resistant grease in them and crimp nicely with any decent pliers. They have internal teeth that are supposed to bite through insulation, but I strip the wires, twist them together before inserting and crimping. They are a lot easier to use than butt connectors for thin wire and will even splice solid and solid to stranded connections.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 19, 2020, 06:57:41 pm
content: Quote from: onesixright on March 19, 2020, 03:08:35 pmYou'd be surprised... I've soldered XLR sockets in auditorium ceilings while at the top of a manlift dozens of feet in the air. While holding the soldering iron over my head since the cables wouldn't reach far below the ceiling itself. It can be done, just be careful and don't stand directly under what you're working on (obviously).With the sole exception of very particular marine situations, I prefer solder over crimped every time. Nothing replaces the reliability of a properly soldered connection. You only want to do this once, right? You don't want to have to revisit those connections after they deteriorate, correct? Solder and heat shrink.

author: Zero999
author_rank: Super Contributor
timestamp: March 19, 2020, 09:40:30 pm
content: Quote from: IDEngineer on March 19, 2020, 06:57:41 pmNo, crimping is far more reliable, than soldering, especially when the joint could vibrate or flex. A soldered joint is relatively brittle, compared to a decent crimp.https://monroeengineering.com/blog/crimping-vs-soldering-cable-connectors-which-is-best/https://millennialdiyer.com/articles/motorcycles/electrical-repair-crimp-or-solder/

author: viperidae
author_rank: Frequent Contributor
timestamp: March 19, 2020, 10:50:48 pm
content: Solder vs crimping is as bad as the tabs vs spaces when it comes to software dev.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 19, 2020, 10:54:11 pm
content: Quote from: Zero999 on March 19, 2020, 09:40:30 pm...which is precisely why I said "With the sole exception of very particular marine situations". In fact, AYBC E-11 electrical wiring standards require crimped connectors in marine applications for exactly that reason, hence my comment. Unless the OP's application involves moving components, and in the absence of additional information, I would continue to prefer soldering for the situation as presently described.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 19, 2020, 10:57:03 pm
content: Quote from: viperidae on March 19, 2020, 10:50:48 pmNah, there's nolegitimatedispute between tabs vs. spaces. Tabs are always and everywhere a better choice. Smaller files, faster parsing, allows the user's own tab setting to generate their preferred on-screen appearance, the list is endless.{takes cover behind nearest scope}

author: Zero999
author_rank: Super Contributor
timestamp: March 19, 2020, 11:29:47 pm
content: Quote from: IDEngineer on March 19, 2020, 10:54:11 pmYou're mistaken. A crimped connection is mechanically more robust than a soldered connection, irrespective of whether it's in a wet or dry environment.You might prefer soldering and find it more convenient, but it doesn't change the fact it's mechanically weaker, than crimping.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 19, 2020, 11:43:25 pm
content: Quote from: Zero999 on March 19, 2020, 11:29:47 pmI said nothing about wet vs. dry. The marine electrical requirements relate to vibration, which is an issue on watercraft. Review my earlier response to you, where I agreed with your statement regarding "vibrate or flex". I quoted AYBC E-11 specifically because it is concerned with vibration and flex, not because of moisture.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 19, 2020, 11:49:17 pm
content: For community benefit, here's the relevant part of E-11:"11.14.3.7: Solder shall not be the sole means of mechanical connection in any circuit. If soldered, the connection shall be so located or supported as to minimize flexing of the conductor where the solder changes the flexible conductor into a solid conductor."This is followed by an explanatory note:"When a stranded conductor is soldered, the soldered portion of the conductor becomes a solid strand conductor, and flexing can cause the conductor to break at the end of the solder joint unless adequate additional support is provided."Note the complete absence of anything relating to wet vs. dry. I suspect they presume anyone doing electrical design for watercraft will either already know to consider that, or will soon learn.

author: Monkeh
author_rank: Super Contributor
timestamp: March 19, 2020, 11:51:07 pm
content: Watercraft are far from the only high vibration environment.What, exactly, about a crimp is going to deteriorate and make it less suitable than solder?

author: IDEngineer
author_rank: Super Contributor
timestamp: March 20, 2020, 12:08:57 am
content: Quote from: Monkeh on March 19, 2020, 11:51:07 pmAgreed, but marine is the only environment I regularly work in where there is an actual RULE about soldered vs. crimped connections. And the OP's environment doesn't sound like high vibration from the info provided.QuoteWe design and manufacture sensors for the marine industry. As a result, we do a lot of R&D in new and existing boats. I long ago lost count of the number of crimped connections we've found loose, dangling, or otherwise disconnected on existing boats. We're talking many, many, many dozens of such broken crimp connections. Usually one of the two wires wiggles free from the crimp itself, leaving the two ends hanging or (worse) lying on the bottom of the hull, potentially exposed to fluids that accumulate there (including water, fuel, and oil).I suspect what happens in many cases is that the additional mass of the crimp itself "jerks" down on the wires during normal watercraft operation. We regularly measure 2-3G shocks on the Z axis from the hull hitting chop, and the crimp experiences that over and over during years of operation. This is the mechanical equivalent of someone yanking on the wires, which over time can lead to one of them pulling out of the crimp.Never once have I seen a "broken" solder connection on a watercraft. I've seen plenty that weren't properly strain relieved, but none that were broken.My solution in such cases is to discard the crimp, solder and heat shrink the connection, and then mechanically support and strain relieve it. This complies with A-11. AYBC *prefers* crimps but allows properly supported soldered connections, as I quoted above. The result is much more reliable than a crimped connection, IMHO. Granted you could get additional reliability out of a crimp by strain relieving it too, but since the spec doesn't require that nobody does it, with the long-term results as described.The funny part is that the watercraft owners/operators often say something like "Yeah, that stopped working a long time ago but we never figured out why." These crimps are often buried behind bulkheads where they are not readily inspectable. Such connections should be made as permanent as possible (such as the technique I described above) on the presumption that no one may ever view them again.

author: Monkeh
author_rank: Super Contributor
timestamp: March 20, 2020, 12:18:29 am
content: Quote from: IDEngineer on March 20, 2020, 12:08:57 amDo you have anything to add outside a very specific example of incorrectly used materials?Putting aside inane solder vs crimp discussion:Small butt-crimps, insulated or not, would be perfectly adequate, as would the gel-filled crimps generally used for phone wiring. Done properly and secured into the wall, they'll outlast the wire. If you're going to bury them in plaster you'll need to take measures to keep moisture out so it doesn't corrode the wire.

author: mark03
author_rank: Frequent Contributor
timestamp: March 20, 2020, 12:24:13 am
content: Quote from: IDEngineer on March 19, 2020, 10:57:03 pmAwww man, the first one to give a categorical answer and it should have had a 50/50 chance of being right, or better, since the correct answer is totally obvious to any reasonable person!! But of course you picked the wrong answer

author: IDEngineer
author_rank: Super Contributor
timestamp: March 20, 2020, 01:11:15 am
content: Quote from: Monkeh on March 20, 2020, 12:18:29 am...or in other words, crimps should not have strain, just as I said.Thank you.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 20, 2020, 01:13:07 am
content: Quote from: mark03 on March 20, 2020, 12:24:13 amI completely agree. The answer IS obvious.EDIT: Don't get me started on the boneheaded nightmare of Python's non-delimited, indent-sensitive code blocking. Whoever thought that up should beg on their knees for forgiveness before Knuth's statue.

author: thm_w
author_rank: Super Contributor
timestamp: March 20, 2020, 09:46:29 pm
content: Quote from: IDEngineer on March 20, 2020, 12:08:57 amWouldn't that indicate an improperly crimped connection?If the connection is intended to be permanent, maybe a ferrule crimp and glue lined heatshrink over top (basically the dolphin item linked above). You might be using that but its not clear.https://nepp.nasa.gov/files/27631/NSTD87394A.pdf

author: onesixright
author_rank: Frequent Contributor
timestamp: March 20, 2020, 11:03:09 pm
content: Quote from: Gregg on March 19, 2020, 05:33:31 pmThanks!Quote from: MarkL on March 19, 2020, 02:42:14 pmAwsome!I found the 3M YU connectors, those seem to do the job (can't find in Europe the Doplhin connectors). I like there is some sort of gel in it that makes them moist resistance.With regard to the debate: solder vs crimp. Here (@EEVBLOG) I learned crimp is better

author: Gregg
author_rank: Super Contributor
timestamp: March 21, 2020, 02:40:46 am
content: I first used Dolphin connectors when I helped a friend install an alarm system 40 years ago; the connections are still working although some of the motion sensors have died. I saw then at the alarm store and thought they looked like they would save some time i.e. my volunteer labor time and my friend was paying for them.Another very good way of connecting alarm wires is to strip both ends, wrap them tightly together, solder them with minimal solder so it doesn’t wick too far along the cables and cover the splice with two layers of heat-shrink with the hot glue inside. Make the outer shrink sleeve longer to help alleviate strains on the splice. The double layer design ensures a really tight fit of the inner sleeve making the splice about as waterproof as you could get.A tip for soldering on a ladder, wrap a couple of turns of solder on the wire and clip off the excess so you don’t have to use a hand to hold the solder.As far as the crimp vs. solder, it depends on the situation. I have never seen really large wire soldered in an industrial setting.