Post by thread:[OT] household wiring connections

>Why DON'T they solder household connections? Is it because they would not >be as easily disconnected and reconnected? It seems to me that things would >be safer,more reliable, and there would be less voltage drop. Actually, LESS reliable! Solder has a much higher resistance than copper which becomes significant at the currents that some household appliances require. I actually have come to believe that the spring type wire nuts (Marettes, Murettes) are FAR more reliable than any other connection I have used in the past. They just have to be installed correctly. I used to do a lot of electrical work (1 year between high school and college) - we used to use T&B Sta-Kon crimp splices. I have since seen many of those splices fail over a period of 15 years or so because they became loose (copper cold flow, I think). I have not seen this happen with a wire nut - the spring stretches while being tightened and keeps the connection under tension. Note: I have seen other brands of wire nuts without the spring - I don't use them and do not know how reliable they are. dwayne Dwayne Reid <spam_OUTdwaynerTakeThisOuTplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 15 years of Engineering Innovation (1984 - 1999) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. My posting messages to Usenet neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.

> I actually have come to believe that the spring type wire nuts (Marettes, > Murettes) are FAR more reliable than any other connection I have used in the > past. They just have to be installed correctly. I used to do a lot of > electrical work (1 year between high school and college) - we used to use > T&B Sta-Kon crimp splices. I have since seen many of those splices fail > over a period of 15 years or so because they became loose (copper cold flow, > I think). I have not seen this happen with a wire nut - the spring > stretches while being tightened and keeps the connection under tension. I have to agree; in the States, each different type of wire nuts are UL listed (not much sure of the reliability of UL) for a certain number of wires at various wire gauges. One in particular that I have used commonly was rated for 2-5 14 gauge, 2-4 12 gauge, and 2-3 10 gauge wires. As long as the wires were within the proper number, the wire nuts made a firm hold that could not come loose. (These also had the metal spring, which would hold onto the wires by making grooves in the exposed copper.) To insure the connection, however, the wires were twisted together tightly using side cutters and the wire nuts were mainly used to cover and hold the joint. If the wires were not twisted together beforehand, I doubt the connection would be as good. Plus, this was with solid copper, not stranded, which my pose a whole different ballfield. > Note: I have seen other brands of wire nuts without the spring - I don't use > them and do not know how reliable they are. If they do not have the metal spring, the plastic threads can become warped or stripped while twisting the nut on the joint, leaving an insecure hold. (Imagine trying to screw a plastic screw into a hole in a sheet of metal...) Regards, -- Michael

Thanks to all who replied on this subject. I guess I will have to try some experiments to prove this to myself. I have always held the statement "A properly soldered connection is a _reliable_ connection" in my mind,and its hard to shake it free :) I kinda find it hard to believe,too,that an average copper-copper twisted connection has less resistance than a properly twised-and-then-soldered one. Solder may have a higher resistivity,but it seems to me that since it fills in all the gaps in the connection,there is greater contact area,and the total resistance is lower. I also find it kinda hard to believe that wires in a 15 to 20 amp circuit get hot enough to soften solder significantly. Since the wires are (or SHOULD be) twisted together before soldering, the combination should be al least as mechanically strong as if it weren't soldered (unless solder acts as a lubricant at temperatures permissible in a junction box). Sean At 03:02 PM 9/19/99 -0600, you wrote: {Quote hidden}>>Why DON'T they solder household connections? Is it because they would not >>be as easily disconnected and reconnected? It seems to me that things would >>be safer,more reliable, and there would be less voltage drop. > > >Actually, LESS reliable! Solder has a much higher resistance than copper >which becomes significant at the currents that some household appliances >require. > >I actually have come to believe that the spring type wire nuts (Marettes, >Murettes) are FAR more reliable than any other connection I have used in the >past. They just have to be installed correctly. I used to do a lot of >electrical work (1 year between high school and college) - we used to use >T&B Sta-Kon crimp splices. I have since seen many of those splices fail >over a period of 15 years or so because they became loose (copper cold flow, >I think). I have not seen this happen with a wire nut - the spring >stretches while being tightened and keeps the connection under tension. > >Note: I have seen other brands of wire nuts without the spring - I don't use >them and do not know how reliable they are. > >dwayne > > >Dwayne Reid <.....dwaynerKILLspam@spam@planet.eon.net> >Trinity Electronics Systems Ltd Edmonton, AB, CANADA >(780) 489-3199 voice (780) 487-6397 fax > >Celebrating 15 years of Engineering Innovation (1984 - 1999) > >* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * >Do NOT send unsolicited commercial email to this email address. >My posting messages to Usenet neither grants consent to receive >unsolicited commercial email nor is intended to solicit commercial >email. > | | Sean Breheny | Amateur Radio Callsign: KA3YXM | Electrical Engineering Student \--------------=---------------- Save lives, please look at http://www.all.org Personal page: http://www.people.cornell.edu/pages/shb7 shb7KILLspamcornell.edu ICQ #: 3329174

On Sun, Sep 19, 1999 at 05:23:40PM -0700, Michael Barker wrote: > To insure the connection, however, > the wires were twisted together tightly using side cutters and the wire nuts > were mainly used to cover and hold the joint. If the wires were not twisted > together beforehand, I doubt the connection would be as good. I worked as an electrician on a construction job for a Summer (actually, as a helper, but I had tools and could think, so they gave *me* a helper and had me work independantly), and we used wire nuts extensively. There was one thing that was drilled into me, though: Do *not* pre-twist the wires. The spring will cut into and hold the wires much more securely if the full side of the wire touches the springs. You want the force of the compression created by twisting the wire nut down onto the wires to be what holds the wires together, not a relatively loose crimp from a pair of pliers. --Bob -- ============================================================ Bob Drzyzgula It's not a problem .....bobKILLspam.....drzyzgula.org until something bad happens ============================================================ http://www.drzyzgula.org/bob/electronics/ ============================================================

On Sun, 19 Sep 1999 17:23:40 -0700 Michael Barker <EraseMEmeb8208spam_OUTTakeThisOuTRITVAX.ISC.RIT.EDU> writes: > As long as the > wires were > within the proper number, the wire nuts made a firm hold that could > not come > loose. I've done a lot of wiring and found that, as with everything else, wire nuts have to be used properly and the user should be aware of their limits. But done properly they will make a quick, relaiable connection. The most vital precaution to using wire nuts is to align the wires so the ends are in the same place before putting the nut on. If one is shorter or longer than the others it will cause one or more wires to be loose. Also, connecting more than 3 wires at a time or wires of widely different sizes with a wire nut is difficult. It is essential to select the proper nut for the number and size of wires involved. Pull on the nut and wires after installing it to test for loose wires. (These also had the metal spring, which would hold onto the > wires by > making grooves in the exposed copper.) To insure the connection, > however, > the wires were twisted together tightly using side cutters and the > wire nuts > were mainly used to cover and hold the joint. I don't like twisting the wires first. The nut does a lot more than "cover and hold" a twisted together joint since the wires are being forced into a conical space as you tighten it. It's important to twist the wire nut on tightly enough that it twists the wires for you. The insulated part of the wires below the nut should start twisting together too. (Hold the wires an inch or so below the nut when tightening). When the insulated part of the wires twists together, the nut is tight enough. Especially in the larger sizes, the type of wire nut with wings on it is easier to tighten by hand. You can also grab the outside of the nut with pliers or use a simple plastic tool made for the purpose to tighten it. > Plus, > this > was with solid copper, not stranded, which my pose a whole different > ballfield. Stranded is about the same but you have to be careful to get all the strands into the nut. Stranded works better with different sizes of wire in the same nut. ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: dl.http://www.juno.com/dynoget/tagj.

At 06:40 PM 9/19/99 -0400, Bob Drzyzgula wrote: >Do *not* pre-twist the wires. The spring will cut into >and hold the wires much more securely if the full side of >the wire touches the springs. You want the force of the >compression created by twisting the wire nut down onto >the wires to be what holds the wires together, not a >relatively loose crimp from a pair of pliers. This I definately agree with. I have actually done some household wiring,too (and,no,I didn't solder <G>), and even with my small amount of experience,I could see that the nuts stayed on better if you didn't twist the wire first. Sean {Quote hidden}> >--Bob > >-- >============================================================ >Bob Drzyzgula It's not a problem >bobspam_OUTdrzyzgula.org until something bad happens >============================================================ > http://www.drzyzgula.org/bob/electronics/ >============================================================ > | | Sean Breheny | Amateur Radio Callsign: KA3YXM | Electrical Engineering Student \--------------=---------------- Save lives, please look at http://www.all.org Personal page: http://www.people.cornell.edu/pages/shb7 @spam@shb7KILLspamcornell.edu ICQ #: 3329174

Hi All: I like wire nuts too. On the subject of soldering: Where absolute reliability and low connection resistance is mandated, we will crimp the wire into a contact, and then add solder to the crimp area. THEN add physical reinforcement to the wire coming out of the back of the crimp to keep it from bending. I've used a lot of crimp terminals and contacts over the years, and have had good luck--provided I matched the terminal to the wire and insulation diameters--AND used the recommended crimping tools (sometimes >$300 for special contacts). There are even special crimp-on's designed to fit the "stick the wire in the hole" type of terminals and provide a solid piece for the screw to clamp down on. Solder forms a rigid joint, and as the solder wicks back up the wire a bit--often under the insulation too--it forms an interface between the rigid part filled with solder, and the wires. IF there is any vibration or bending, it will fail at this point. There is also metallurgical stuff going on that can make the joint more brittle as well. I think electricians (as opposed to electronic types) have never been trained to solder, don't have the equipment, use acid core solder, and general y screw things up--mostly out of ignorance--and occasionally stupidity. Electrical Codes are intended to supplant thinking on the part of the installers, and so become somewhat dogmatic--but hard to create a hazardous situation when followed. Main emphasis is on FIRE safety--not shock hazard. Bad joints can get HOT. Enjoy Kelly William K. Borsum, P.E. -- OEM Dataloggers and Instrumentation Systems <KILLspamborsumKILLspamdascor.com> & <http://www.dascor.com>