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#1
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Wire connector?
Hello,
This is pretty basic. I have a small on/off switch that controls some box lighting. There are two thin single-strand wires running to the on/off switch (red and black). I noticed that one of the wires disconnected from its terminal. It appears to have been soldered with a piece of shrink tubing over it. There is no connector as such - just a little thin post that the wire attaches to. The problem is that the wire is very short and the switch is located in the back of the box making it very difficult to reach. I have to use long tweezers just to reach it. Is there any clever way to try and re-attach the wire to the post? I was thinking that liquid solder or something might be possible. Any ideas? Thanks, Bob |
#2
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Wire connector?
BobK wrote:
Hello, This is pretty basic. I have a small on/off switch that controls some box lighting. There are two thin single-strand wires running to the on/off switch (red and black). I noticed that one of the wires disconnected from its terminal. It appears to have been soldered with a piece of shrink tubing over it. There is no connector as such - just a little thin post that the wire attaches to. The problem is that the wire is very short and the switch is located in the back of the box making it very difficult to reach. I have to use long tweezers just to reach it. Is there any clever way to try and re-attach the wire to the post? I was thinking that liquid solder or something might be possible. Any ideas? Thanks, Bob What are the consequences, if the wire falls off while the device is running ? Can someone get a shock ? Could a fire start ? "Fix it right" comes to mind. Solder is not the best means, in the first place. It all depends on the environment. For example, if the wire is subject to stress and strain, pulling on solder can lead to eventual failure. It can also concentrate stress in the wire (at the "bend point"), causing the wire to break. And that might be why it broke in the first place. Take this as an example. Two pieces of wire laying next to each other. With insulation removed. -------------- ---------------- If you soldered the joint there, the solder would be the sole means of mechanical support. If the solder cracks, the two ends flop about. On the other hand, you could twist the wire together. In that case, the contact of the wire to wire, is helping with the mechanical support, so there is less stress on the solder in the joint. And even if the solder joint was "cold" or a bad joint, the wire can provide secondary support. ---------+ +--------- \ / X / \ Twisted wire helps provide mechanical \ / support. X / \ Some switch terminals, have a hole in the tab, and the wire can go through that. That is much more secure, than surface solder, like my first drawing above. Note that solder is also not a good candidate, for things where there are other kinds of obvious stresses. Like, say, an item that could get hot enough, that the solder could remelt and drip off. If the terminals on the switch were thin rectangles, of the appropriate size, you could use these. A stranded wire is crimped underneath the insulated part. The "jaw" part on the other end, slide over the thin rectangle. http://www.radioshack.com/product/in...ductId=2104091 If the switch terminal is "dirty", you cannot use a connector like that. Solder debris on the rectangular terminal, will prevent that connector from gripping properly. So the crimp style connector, should only be used on a new, clean, switch. Just do it right, and sleep better at night. Imagine a house full of "half right" repairs... What risk would you run ? What are the house insurance implications, of a bad user repair that causes a fire ? Paul |
#3
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Wire connector?
Hello,
This is pretty basic. I have a small on/off switch that controls some box lighting. There are two thin single-strand wires running to the on/off switch (red and black). I noticed that one of the wires disconnected from its terminal. It appears to have been soldered with a piece of shrink tubing over it. There is no connector as such - just a little thin post that the wire attaches to. The problem is that the wire is very short and the switch is located in the back of the box making it very difficult to reach. I have to use long tweezers just to reach it. Is there any clever way to try and re-attach the wire to the post? I was thinking that liquid solder or something might be possible. Any ideas? Thanks, Bob What are the consequences, if the wire falls off while the device is running ? Can someone get a shock ? Could a fire start ? "Fix it right" comes to mind. Solder is not the best means, in the first place. It all depends on the environment. For example, if the wire is subject to stress and strain, pulling on solder can lead to eventual failure. It can also concentrate stress in the wire (at the "bend point"), causing the wire to break. And that might be why it broke in the first place. Take this as an example. Two pieces of wire laying next to each other. With insulation removed. -------------- ---------------- If you soldered the joint there, the solder would be the sole means of mechanical support. If the solder cracks, the two ends flop about. On the other hand, you could twist the wire together. In that case, the contact of the wire to wire, is helping with the mechanical support, so there is less stress on the solder in the joint. And even if the solder joint was "cold" or a bad joint, the wire can provide secondary support. ---------+ +--------- \ / X / \ Twisted wire helps provide mechanical \ / support. X / \ Some switch terminals, have a hole in the tab, and the wire can go through that. That is much more secure, than surface solder, like my first drawing above. Note that solder is also not a good candidate, for things where there are other kinds of obvious stresses. Like, say, an item that could get hot enough, that the solder could remelt and drip off. If the terminals on the switch were thin rectangles, of the appropriate size, you could use these. A stranded wire is crimped underneath the insulated part. The "jaw" part on the other end, slide over the thin rectangle. http://www.radioshack.com/product/in...ductId=2104091 If the switch terminal is "dirty", you cannot use a connector like that. Solder debris on the rectangular terminal, will prevent that connector from gripping properly. So the crimp style connector, should only be used on a new, clean, switch. Just do it right, and sleep better at night. Imagine a house full of "half right" repairs... What risk would you run ? What are the house insurance implications, of a bad user repair that causes a fire ? Thanks for the advice. This is single strand wire and the terminal looks like it is the same size as the wire. That is, the terminal is a small wire sticking out of the device. There does not seem to be any crimping type connector on the wire. So if I did something like adding a connector, it would have to be crimped to the wire and have a very small female to catch the terminal. Does something like that exist? Thanks Again, Bob |
#4
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Wire connector?
BobK wrote:
Thanks for the advice. This is single strand wire and the terminal looks like it is the same size as the wire. That is, the terminal is a small wire sticking out of the device. There does not seem to be any crimping type connector on the wire. So if I did something like adding a connector, it would have to be crimped to the wire and have a very small female to catch the terminal. Does something like that exist? Thanks Again, Bob If you have two wires to join together, you can use "wire nuts". These work best with stranded wire. There is a thing, like a coil spring, inside the plastic. The coil spring grips the wire, as the nut is twisted onto the ends of the wire(s). You twist the wires together first, then twist the wire nut onto the wire ends. The direction of twist of the wires, should be consistent with what the wire nut is going to do to the wire when twisted on - the wire nut should serve to twist the wires in the same direction as the original twisting. http://www.productdose.com/phpwiki/u...c2530d_pop.jpg You can see some wire nuts in this picture. http://www.bfranker.badz28.com/fbody/scan36.JPG In my personal experience with wire nuts, their performance is quite variable. For example, if I took one solid wire and one stranded wire, the wire nut would not stay on the end of the twisted together bare wire ends. When selecting wire nuts, you select them according to the number of wires to be connected, and the gauge of each wire. In my own case, I like to buy a "variety pack", which contains samples of various size wire nuts. Then I check the charts, and experiment with the two closest sizes, to find one that seems the most secure. I'd repaired appliances, like lamps for illuminating your home, with wire nuts. I put the thing all back together again, then disassembled, only to find a wire nut had worked loose. So I consider them to be dangerous, and in fact, you're relying on the twisting together of the original wires ends, about as much as you're relying on the wire nut. The benefit of the wire nut, is it compresses the wires, without replying on the stiffness of the twisted wires. So in theory, it should provide a superior, gas tight connection. But the devil is in the details - if not fitted correctly, they just don't grip very well. I hope I've made their deficiencies clear enough. Are you sure you cannot remove the switch, and fit a new switch which is compatible with crimp fittings ? Even with crimp fittings, it takes good tools to do a good crimp. If you're going the crimp route, buy plenty of extra materials (wire and crimp terminals), and practice until you're no long breaking strands of wire, or leaving strands loose outside the crimp. It takes some practice before you get good at it. How good the job has to be, depends on the amount of current the circuit is carrying. For example, a bad connection in a heating device, will result in high wire temperatures, and even if the wire has high temperature insulation, it can bake off. There is another kind of crimp, but this one makes me nervous as well. Especially if you were working in a cramped location, and were unable to check for damage to the wire caused by the crimping. Any time you work with wire, you have to check for nicks that cause the wire to break. If you have a thin wire, and the crimp requires a lot of force to be applied to the tool, it would be easy to transfer some of that force to the wire, while working on it. While I have some of these in crimp variety packs I've bought, I don't use these. http://www.radioshack.com/product/in...ductId=2151268 Crimp terminals come in male and female. Now, think about these for a moment. If you connected one of the males to one of the females, the metal ends would not be covered by insulation. So this would not be safe, unless extra insulation was applied some how. These would be better in a situation, where the device you were connecting to, was bolted to the chassis, and could not move. http://www.radioshack.com/product/in...ductId=3060975 So not everything you find at the Radio Shack, is safety minded. Some of the stuff, is downright dangerous. Another thing you can find at Radio Shack, is heat shrink tubing. This stuff is usually made from Polyolefin (a name you can use as a search term, if necessary). It shrinks to half its normal diameter, when heated. So what is the problem with this stuff ? Well, the temperature at which it shrinks, can be higher than the melting point of ordinary wire insulation. When you apply hot air to the polyolefin, the rest of the wire insulation pulls away from the wire. So again, not the best material for every application. I still use it, but like in the other examples - practice, disassemble, and inspect for damage or deficiency, before making a final repair. I consider this stuff to be more reliable than electrical tape, which can become gooey and migrate away from where it is applied. http://www.radioshack.com/product/in...ductId=2062662 The store I buy my Polyolefin from, sells it in 3 foot lengths, and I keep about five or six different diameters in stock. The temptation is usually to make it fit too tight when you buy it, so buy the size you think would fit, and also buy a piece of the next largest one. http://en.wikipedia.org/wiki/Heat_shrink_tubing Paul |
#5
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Wire connector?
Even with crimp fittings, it takes good tools to do
a good crimp. If you're going the crimp route, buy plenty of extra materials (wire and crimp terminals), and practice until you're no long breaking strands of wire, or leaving strands loose outside the crimp. It takes some practice before you get good at it. How good the job has to be, depends on the amount of current the circuit is carrying. For example, a bad connection in a heating device, will result in high wire temperatures, and even if the wire has high temperature insulation, it can bake off. There is another kind of crimp, but this one makes me nervous as well. Especially if you were working in a cramped location, and were unable to check for damage to the wire caused by the crimping. Any time you work with wire, you have to check for nicks that cause the wire to break. If you have a thin wire, and the crimp requires a lot of force to be applied to the tool, it would be easy to transfer some of that force to the wire, while working on it. While I have some of these in crimp variety packs I've bought, I don't use these. http://www.radioshack.com/product/in...ductId=2151268 Crimp terminals come in male and female. Now, think about these for a moment. If you connected one of the males to one of the females, the metal ends would not be covered by insulation. So this would not be safe, unless extra insulation was applied some how. These would be better in a situation, where the device you were connecting to, was bolted to the chassis, and could not move. http://www.radioshack.com/product/in...ductId=3060975 So not everything you find at the Radio Shack, is safety minded. Some of the stuff, is downright dangerous. Another thing you can find at Radio Shack, is heat shrink tubing. This stuff is usually made from Polyolefin (a name you can use as a search term, if necessary). It shrinks to half its normal diameter, when heated. So what is the problem with this stuff ? Well, the temperature at which it shrinks, can be higher than the melting point of ordinary wire insulation. When you apply hot air to the polyolefin, the rest of the wire insulation pulls away from the wire. So again, not the best material for every application. I still use it, but like in the other examples - practice, disassemble, and inspect for damage or deficiency, before making a final repair. I consider this stuff to be more reliable than electrical tape, which can become gooey and migrate away from where it is applied. http://www.radioshack.com/product/in...ductId=2062662 The store I buy my Polyolefin from, sells it in 3 foot lengths, and I keep about five or six different diameters in stock. The temptation is usually to make it fit too tight when you buy it, so buy the size you think would fit, and also buy a piece of the next largest one. http://en.wikipedia.org/wiki/Heat_shrink_tubing Thanks again for the lesson and the links. A couple of points of clarification: The wire I am dealing with is not stranded. It is one solid piece of wire. It is about the same gage as the thin individual wires running all around the box. Also, there is no push or pull stress on the switch or wires. The switch is just sitting there by itself. Having said that, I appreciate the cautions you gave me and will proceed in that direction. Of all the connectors you linked to, the one that seems most likely is the Crimp-on Butt Connector at http://www.radioshack.com/product/in...ductId=2151268 . The only problem is going to be getting the crimping tool into the tight space. I may have to pull things apart to get to it. Thanks Paul, Bob |
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